3/4/2021
Concrete Paving in Minnesota
• Joint Effort • Minnesota Department of Transportation (MnDOT) • Concrete Paving Association of Minnesota (CPAM) • Recognized nationally as a leader • Our specifications, standards, industry and equipment are often recognized as the most modern and 2021 CONCRETE PAVING CLASS progressive • We need to strive to continue our national leadership role.
2 12
Instructors Objective of Course
• MnDOT The primary objective of this training course is to educate the • Maria Masten –Concrete Engineer concrete pavement inspector for the purpose of ensuring “Good Practices” during the concrete pavement construction • Rob Golish – Assistant Concrete Engineer process. • Gordy Bruhn –Concrete Field Engineering Specialist
• Concrete Paving Association of MN (CPAM) • Matt Zeller –Executive Director
3 4 34
What Drives Concrete Pavement Performance in Importance of Inspection Minnesota?
• Durability Proper inspection: • Materials • Workmanship Key role in providing a well constructed high‐quality pavement. • Smoothness Influence performance quality and the ride quality. • What the travelling public cares about A quality concrete pavement is directly related to a well constructed concrete pavement.
• How do we get there? High quality concrete pavements provide excellent long‐term • Effective Inspection Program performance and ride over the design life with a low level of • Emphasis on Quality maintenance and rehabilitation. • Use of Incentives 6 56
1 3/4/2021
Quality Understanding and Accepting Material Quality Variability
• Quality as defined by the American Society of Civil Engineering (ASCE) • “Differences in measured test values for a given Quality Characteristic within a stable pattern due to chance, or outside this normal pattern due to assignable cause.” • “Quality is never an accident. It is always the result of high intentions, intelligent direction, and skilled execution. It represents a Material Process Sampling Testing wise choice amongst many alternatives.”
Composite Variability
7 8 78
Quality Assurance Defined 23 CFR 637 Quality Control
• Uses real time feedback Agency Acceptance Contractor Quality Control • A good Contractor QC system:
State processes, • Doesn’t try to accommodate Agency requirements • Qualified (certified) Personnel independent of material • Implements QC procedures as standard practice • Qualified Laboratories } • Isn’t just paperwork…it’s a mindset • Independent Assurance • Dispute Resolution for Test Results
910
How Did We Get Contractor Buy In To These Ideas?
Communication!!! Contractors need to know what the objectives are Contractors need to know what has worked and what hasn’t Allow for mistakes and failure Shared Agency/Industry Risk Use of Incentives to Achieve Quality Reward excellence and innovation Encourage new ideas Maria Masten Offer a carrot (incentives) instead of a stick!!!
12 11 12
2 3/4/2021
MnDOT Concrete Paving Incentives and Disincentives Should we use incentives?
• Aggregate Quality • Use of incentives will generally bring better quality contractors • Max Incentive $2.00/CY $7.00/CY at the • Contractors bid some of the incentives in, therefore you will either pay • Max Disincentive $2.00/CY PLANT ~ Full time now or pay later • Optional Well‐graded aggregate • Max Incentive ‐ $2.00/CY paving plant monitor • Costs are incurred at project end which means…. • W/C Ratio • You budget for them • >0.37 and <0.40 –Max incentive $3.00/CY Fly ash • You pull out of the general construction budget • >0.39 and <0.42 –Max incentive $3.00/CY Slag, ternary, cement only • Max Disincentive $3.00/CY • You may need to meet with county board and ask for additional money • Ride (Smoothness) • You use a pay item to accrue the money up front • Max Incentive ‐ $890‐1240 per 0.1‐mile segment • Max Disincentive –(‐$890‐1240) per 0.1‐mile segment 14 13 14
W/C Spec Impact on Strength (C39)
Investigation of Benefits of the MnDOT w/c Specification
Pre-1996 (19 projects) 1996 & After (15 projects)
FINAL REPORT: http://www.dot.state.mn.us/research/reports/2018/201825.pdf 15 16
W/C Spec Impact on Permeability (C1202) W/C Spec Impact on Chloride Penetration
• All tests performed on cores taken midpanel • The key is keeping the Lower Permeability chemicals out -Concrete holds less water PRE w/c POST w/c -Fights the ingress of deicers -Lower critical saturation level -Can’t transport as much water
17 18
3 3/4/2021
How Are We Doing? Where do the specs go from here?
• Address fly ash supply issues • Contractors believe in and buy into the incentive system. • Review ASR Requirements • After 20 years little signs of deterioration • Review Incentives • Any noticeable defects appear to be workmanship related issues • Focus w/c ratio on reducing total cementitious • Smoothness has improved • Phoenix Testing • Durability has improved • Shadow Testing in 2021 • Pilot Projects in 2022 • Implementation in 2023 • Super Air Meter • Shadow Testing in 2021 • Try on some pumping projects
19 19 20
Considerations when designing a concrete paving project
• Pavement Type • Safety Edge • Pavement Thickness • Rumble Strips • On Grade or Overlay • Maintenance of Traffic • Joint Spacing Designing a Concrete Paving Project • Shoulder Type • Pavement Load Transfer Maria Masten • Seal joints
21 22 21 22
Components of a Concrete Pavement Pavement Design
• Pavement Design Engineer –Tim Anderson • Pavement Design Manual • http://www.dot.state.mn.us/materials/ pvmtdesign/manual.html • Concrete Engineering Unit • Concrete Paving Association of MN
23 24 23 24
4 3/4/2021
Pavement Design Tools Concrete Pavement Types
25 26 25 26
Concrete on Grade Guide to Concrete Overlays
Typically 7.0” or thicker 15 foot – uniform spacing https://intrans.iastate.edu/app/uploads/2018/08/Overlays_3rd_edition.pdf
27 28 27 28
Unbonded Concrete Overlay on Concrete Pavements Unbonded Concrete Overlay on Composite Pavements
7.0” or thicker 15 foot – uniform spacing 29 7.0” or thicker 12 foot – 15 foot joint spacing 30 29 30
5 3/4/2021
Unbonded Concrete Overlay Interlayer PASSRC –Permeable Asphalt Stabilized Stress Relief Coarse Types Used in Minnesota
• PASSRC –Permeable Asphalt Stabilized Stress Relief Coarse Layer • Virgin Hot Mix Asphalt • Milled Hot Mix Asphalt • Non‐woven geotextile fabric
31 32 31 32
Hot Mix Asphalt –Virgin or Milled Surface Non‐woven Geotextile Interlayer
HMA Interlayer Milled Surface - White-topping or Baskets more apt to move on HMA Unbonded Overlay surface
HMA over PCCP
Milled Surface
Do not correct geometry w/ HMA OK to mill geometry corrections 33 34 33 34
PCC Overlay Design – Unbonded OL Unbonded Concrete Overlay on Asphalt Pavements
• Localized patching with HMA • Correct superelevations with HMA • Correct crown in concrete • Interlayer options • PASSRC (1” –2”) – dependent upon faulting • HMA (1” –2”) – dependent upon faulting • Geotextile Fabric (1/4”) –not recommend for faulted concrete
35 7.0” or thicker 12 foot – 15 foot joint spacing 36 35 36
6 3/4/2021
Unbonded Concrete Overlay on Asphalt Pavements ‐ Whitetopping PCC Overlay Design ‐ Whitetopping
• Milling the asphalt is typical to reduce grade adjustments • Profile Mill or Mill to a Uniform depth? • Mill to or past an existing lift line • Leave a minimum of 3” ‐ 4” of asphalt in place • Depending on roadway type and traffic • Needs to support construction traffic • Minimum of 3” of “good” asphalt • Patch working cracks and potholes prior to overlaying • Correct the crown in concrete • Use of fiber reinforcement 6.5” thick or less 6 foot – 7 foot joint spacing 37 38 37 38
Joint Spacing, Dowel Bars and Tie Bars Dowel Bar Requirements (3302)
PCC Longitudinal Transverse Dowel Bar All Longitudinal Thickness Joint Spacing Joint Spacing Diameter Joints (inches) (Panel Width) (Panel Length) (inches) • Epoxy Coated Steel Dowel Bars (AASHTO M254 Epoxy)
≥ 10 ½ 12’ – 14’ 15’ 1 ½ No. 5 tie bars or (36” long)
8‐10 12’ – 14’ 15’ 1 ¼ No. 4 tie bars • Epoxy Coated Galvanized Tubular Dowel Bars (ASTM A1078 (30” long) Type 2 Epoxy)
7 & 7.5 12’ – 14’ 15’ 1 No. 4 tie bars (30” long)
6 & 6.5 6’ – 8’ 6’ None No. 4 tie bars (30” long)
4 ‐5.5 6’ – 8’ 6’ None None, unless using Figure 510.4 39 40
39 40
High Performance Dowel Bar?? Use of fibers instead of dowel bars?
• Typically used within the Metro 494/694 loop • Can be found on the Approved Products List • Mechanism to replace dowel bars for load transfer in thinner pavements (6” or less)
41 41 42
7 3/4/2021
Use of Fibers in Thin Concrete Overlays and Whitetopping MnDOT Current Joint Sealing Guidance
• Sawing • 1/8” – 3/16” single sawcuts (no widening) • Seal the following: • All Roadways: Speed limit 45 mph or less • Whitetopping < 6” thick • Concrete Pavement Repairs • Use hot poured, extra low modulus, elastic type joint sealant Currently • DO NOT seal: Twig, MN under study Rochester, MN • The rest 5” Unbonded OL by MnDOT 6 ½” Whitetopping • Consider the 5‐year plan: on HMA interlayer 12’ undoweled • Go back in and fix any misaligned dowel baskets 12’ undoweled panels panels • Seal joints after the concrete has stopped shrinking
43 44
Shoulders and Pavement Widening Pavement Widening on Whitetopping
• Concrete vs. Bituminous Edge broke off – removed some and • Inside and Outside Shoulder Widths bridge the rest with rebar • Same thickness as mainline?
46 45 46
Specifications and Provisions Typically Used
(1717) Air, Land, and Water Pollution (Concrete Grinding)
(2011) Construction Surveying for Asphalt Bond Breaker Layer Under Concrete Overlays
(2232) Milled Rumble Strips (Concrete) AND/OR (2232) Milled Sinusoidal Rumble Strips (Concrete)
(2301) Concrete Pavement MnDOT Specifications and Special Provisions (2301) Dowel Bar AND/OR (2301) High Performance Dowel Bar (2363) Permeable Stabilized Stress Relief Course (PASSRC) and Permeable Asphalt Stabilized Base (PASB) Maria Masten (2399) Pavement Surface Smoothness
(3733) Geotextiles – Geotextile Fabric Bond Breaker Interlayer for Concrete Overlay
47 48 47 48
8 3/4/2021
Where do I find the 2301 Concrete Specs? Spec 2301 ‐ Concrete Paving Placement Methods
MnDOT is currently using the 2018 Spec Book
Review the Special Provisions in the Contract for changes to the Spec Book
The next Spec Book will be 2020
Slipform Paving Fixed Form Paving -Specs written around slipform process 49 50 49 50
Constructing the Concrete Overlay
• Concrete Overlay construction is simply regular concrete construction on an existing surface
Measurement and Payment
Maria Masten
51 52 51 52
2018 Spec Book Pay Items Pay Items 2301.5 Basis of Payment
Item No.: Item: Unit: Option A (Concrete Pavement) • Square Yard Only (Uniform Thickness) 2301.502 Dowel Bar each • Placed On Grade (e.g., New Construction Projects) 2301.502 Dowelled Expansion Joints, Design ___ linear foot • Concrete Pavement ___ in (square yard)
2301.503 Integrant Curb, Design ___ linear foot
2301.504 Concrete Pavement ___ in square yard Option B (Place Concrete Pavement) 2301.504 Concrete Pavement ___ in High‐Early square yard • Square Yard and Cubic Yard (Variable Thickness)
2301.504 Place Concrete Pavement ___ in square yard • Whitetopping and Unbonded Overlays
2301.507 Structural Concrete cubic yard • Place Concrete Pavement ___ in (square yard)
2301.507 Structural Concrete High‐Early cubic yard • Structural Concrete (cubic yard)
2301.508 Supplemental Pavement Reinforcement pound 53 54 53 54
9 3/4/2021
Pay Item ‐ Concrete Pavement Yd² /Inch Pay Item ‐ Structural Concrete Yd³ Fine Grading – Plant-Lab Office – Batching Concrete - Forming
• The Engineer will field (Average End Area) calculate the volume of Structural Concrete and Structural Concrete High Early placed.…Due to variations in the asphalt or asphalt bond breaker layer, the Contractor may request additional volume up to 102 percent of the Engineer’s field calculated final volume of Delivering – Depositing –Placing – Spreading ‐ Screeding Structural Concrete, Structural Concrete High Early¸ or both for the entire project.
• The Engineer will verify additional volume of concrete from the computerized batch ticket printouts from the plant, with consideration of any waste.
• If the Engineer finds the Contractor’s request for the additional final volume valid, Finishing – Curing – Protecting – Sawing and Sealing the Engineer will pay for the additional volume up to 102 percent of the calculated quantity for the entire project.
55 56 55 56
Pay Item ‐ Structural Concrete Yd³ Pay Item – Structural Concrete High‐Early Yd³
The contract cubic yard price for Structural Concrete and Structural Concrete High‐Early includes: • If the plans include a separate contract item for Structural Concrete High‐Early or if the Contractor requests high‐ • Cost of the batch materials, mixing operations, and the plant‐lab office. early and the Engineer approves, the Department will not • Producing, delivering, and depositing the concrete provide extra compensation for the production of high‐ early strength concrete. • Do I need a High‐Early Pay Item? Discuss with Construction • In front of a business • Intersection leave outs • Temp Construction • Bit guys want to pave adjacent as soon as possible
57 58 57 58
Pay Item‐ Supplemental Pavement Reinforcement Reinforcement Bars –Not a Pay Item aka Culvert Steel
• The Engineer will measure supplemental pavement reinforcement over culverts, storm sewers, and water mains, by weight. • The Engineer will not separately measure tie bars, taper steel, stopper bars, and other reinforcement bars. • The Contract pound price for Supplemental Pavement Reinforcement includes the cost of furnishing and placing the metal reinforcement, including tie wires, supporting devices, and splicing. • Reinforcement bars will be considered incidental to the cost of concrete pavement.
59 60 59 60
10 3/4/2021
Stopper Bars and Taper Steel –Not a Pay Item Headers –Not a Pay Item
• Incidental item – reinforcement bars no • All headers will be considered incidental to the cost of concrete pavement. longer a pay item • Be sure to indicate the location of the terminal headers in • Size of reinforcing bars the plans. • All bars should be 30” long and spaced 4” from transverse joint, 3” from longitudinal joint and 6” from each other
61 62 61 62
Pay Item ‐ Integrant Curb Pay Item –Dowel Bars
• The Contract linear foot price for Integrant Curb, Design ___ • The Engineer will measure dowel bars by the actual includes the cost of forming and finishing the curb and protecting number of individual dowels placed. and curing the concrete. • The Contract price for Dowel Bars includes the cost of furnishing and placing the materials as specified.
63 64 63 64
Incentives/Disincentives –Measurement and Payment Daily Accomplishment Report
• If the contract includes the contract item Concrete Pavement, the Engineer will apply incentive or disincentive for Concrete Pavement • MnDOT Tool used for based on the theoretical volume of concrete used by multiplying documenting –not the measured square yard of concrete by the thickness shown in the plans. required • However, DOCUMENTING QUANTITIES IN WRITING IS • If the contract includes the contract item Structural Concrete, the REQUIRED! Engineer will apply incentive or disincentive based on the daily cubic yards batched of Structural Concrete as verified by the computerized batch ticket printouts from the plant, with consideration of any waste.
65 66 65 66
11 3/4/2021
Standards Plans and Plates
• Standard Plans in the 200 series (5‐297.2xx)
• Standard Plan 5‐297.221 – Pavement Joints (updated in 2020)
• Standard Plate 1103x ‐ Typical Dowel Bar Assembly (updated in 2020)
• Standard Plate 1150x ‐ Construction of Header Joint (deleted and MnDOT Standard Plans and Plates added to Standard Plan 5‐297.221)
• Standard Plate 1070x – Supplemental Pavement Reinforcement Rob Golish • Standard Plate 1210x –Concrete Pavement Adjacent to Railway Crossing
67 68 67 68
Standard Plan 5‐297.209 Standard Plan 5‐297.217 (Sheet 1 of 2) Acceleration and Deceleration Lane (Rural) Concrete Mainline Pavement (15 ft – Rural)
69 70 69 70
Standard Plan 5‐297.217 (Sheet 2 of 2) Standard Plan 5‐297.219 Concrete Mainline Pavement (15 ft – Urban or Concrete Shoulders) Concrete Ramp/ Loop Pavement
71 72 71 72
12 3/4/2021
Ramps/Loops Standard Plan 5‐297.221 ‐ Contraction Joints
• In most cases ‐ longitudinal joint (L1T) Here are some highlights of the changes: goes down the center of the ramps (8’‐8’). • Ramps that are 16’ wide with integrant • New requirement for contraction joint depth is T/3 for curb everything. Was T/3 for overlays and T/4 for new • Design with an L1T joint down the middle (8’ construction. mark) • New placement requirement of the dowel basket is 12” from • No L2T joints at the curb lines the centerline. Was 6” from the centerline. • Added 8 bar basket design (only used on unbonded overlays). • Removed silicon sealed joints. • Contractors option to cut and bend spacer wires after staking.
73 74 73 74
Standard Plan 5‐297.221 ‐ Longitudinal Joints
Here are some highlighted changes: • Contractors option to use keyway when: 1. Placing fixed form construction 2. Placing slipform construction with a design thickness of 10 inches or greater • Use of keyway for any other application requires approval of the Engineer. • New detail showing location of tie bar when adding curb & gutter
75 76 75 76
Standard Plan 5‐297.221 – Construction Headers
Reinforcement Bar Header: • Eliminated Standard Plate 1150. • When T > 10 ½” No. 4 Bars 30” Long Spaced 12”. • When T ≥ 10 ½” ” No. 5 Bars 30” Long Spaced 12”. • 2 options: 1. Slipformed Placed 2. Fixed Form Placed
77 78 77 78
13 3/4/2021
Standard Plan 5‐297.221 – Standard Plan 5‐297.221 – Construction Headers Terminal Headers
Dowel Bar Header: • Use when abutting to bituminous • Eliminated Standard Plate (No. 7 reinforcement bar 5’ long 1150. spaced 18” on center) • 3 options: • Do not use a terminal header on 1. Slipformed Placed short concrete sections (less than 2. Fixed Form Placed 200 feet) abutting bituminous (e.g., 3. Drill and Grout side streets, etc.)
79 80 79 80
Standard Plate 1103 Supplemental Pavement Reinforcement
• Added an eight dowel basket • Removed the three dowel basket • Required to coat the entire dowel bar assembly with bond breaker before delivery to the site • Three dowel basket heights DRAFT 81 82 81 82
Supplemental Steel Standard Plate 1070 Reinforcement in Overlay Supplemental Pavement Reinforcement Transition Areas
• Standard addresses culverts, storm sewer • Currently found in the Facility Design Guide and water mains (FDG)
• Supplemental Reinforcement not needed • Will be putting together a standard plan over existing (undisturbed) culvert unless sheet there are differential settlement concerns • #5 reinforcing spaced at 1’ on center in the • Rebar spacing is longitudinal direction and 2’ x 2’ max • #5 reinforcing bars spaced at 2’ on center in the transverse direction
83 84 83 84
14 3/4/2021
Transition from an unbonded overlay to an on‐grade pavement
Technical Memorandums
Rob Golish
See the FDG manual 85 86 85 86
Safety Edge Expired Technical Memorandum No. 11‐02‐T‐02 Safety Edge
• Discussing possible changes to MnDOT Safety Edge Design • Use of safety edge – District Traffic Engineer • Doing this will save materials costs for concrete determined • Longitudinal joint saw wheel can ride edge of slab • Will reduce the width of the paving platform that the contractor needs to provide.
87 88 87 88
Safety Edge Rumble Strips Potential New Design for the Facility Design Guide (FDG) Technical Memorandum No. 17‐08‐T‐02
• Edgeline or structural rumble strips • Shoulder rumble strips • Centerline rumble strips (new requirements)
• See Memorandum to determine what is required
89 90 89 90
15 3/4/2021
Joint layout review
Send joint layouts to the Concrete Engineering Unit for review at 60% design stage or Plan Review earlier if ready
Rob Golish
91 92 91 92
CONCRETE PAVING PLAN 60% CONCRETE PAVING PLAN 100%
• With the taper in the middle, the Contractor will need to stop the paver before and after the taper and come • Moved the taper from the middle to the outside to allow for the Contractor to pave through the back and pave the area of the taper later. intersection without stopping. • Issue: construction headers need to be installed, higher ride numbers, additional time, higher bid price. 93 • Result: better ride and better concrete. 94 93 94
Contract Review
Review the Contract to determine what specifications apply to the project related to testing rates, mix requirements, incentives and disincentives, etc. Hold a pre‐pour meeting if possible. Contact the Concrete Unit with questions Pre‐pour meeting
Rob Golish
95 96 95 96
16 3/4/2021
Project Team –Agency & Contractor(s) Concrete Paving Pre‐Pour Meeting
• Communication Why? • Partnering • Information must be readily available in a timely manner for • Both are a two‐way street done with respect and timeliness everyone involved to perform their functions. • Great deal of time, money, and effort involved • Paving operation happens quickly "In any moment of decision, the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you • One shot at getting it right can do is nothing."
97 98 97 98
Concrete Paving Pre‐Pour Meeting Contractor Quality Plans Required
Purpose: • Cold Weather Protection Plan if weather conditions • Discuss the upcoming paving operation. require • Discuss Owner expectations. • Anchoring Dowel Basket Assemblies • Review project specifications and special provisions. • Early‐Entry Sawing Method • Review material and quality requirements. • Listen to Owner and Engineers concerns. • Jointing plan if placing curb and gutter before concrete • Listen to Contractors concerns. pavement • Discuss potential problems or issues. • Establish a line of communication and chain of command. • Discuss traffic control and safety.
99 100 99 100
Certifications
• All Contractor and Inspection Personnel performing Testing MUST BE Certified
• Request to see Contractor’s MnDOT Technical Certification Card Maintenance of Traffic • Know the certifications and people at the beginning of the project
Matt Zeller
101 102 101 102
17 3/4/2021
How to Deal With Traffic and Stringlines? Paving With No Shoulders
103 104 103 104
Single Lane Paving Congestion Associated with Stringlines & Single Lane Paving
• Contractors will figure out how to do it • Contractors will work with the residents and/or businesses on roadway
105 106 105 106
Congestion Associated with Stringline & Paving with Outside & Inside Stringlines Paving ‐ 1st Pass
107 108 107 108
18 3/4/2021
Paving with Outside Stringline Only & Slope Control Outside Edge Stringline Only ‐ 1st Pass ‐ 2nd Pass
109 110 109 110
Anoka Co Anoka Co
111 112 111 112
Sample Language for MOT TH 24 –4” Whitetopping MOT
• In plans and specs, provide contractor with clear • The Contractor shall maintain, at all times, the existing traffic movements at criteria for maintenance of traffic (from Guide to the following intersections: Meeker CSAH 34 and Meeker CSAH 14. Concrete Overlays, 3rd Edition) • The Contractor shall maintain a lane width of not less than 12 feet in each direction • Two lanes in each direction at all times • Pilot car queue should not exceed 10 minutes • Several staging examples in Chapter 6 –Work Zones – consider conventional paver not zero‐clearance
113 114 113 114
19 3/4/2021
TH 59 –5” Whitetopping MOT MN 4 –7” Urban grading MOT
• (A) Through traffic on T.H. 59 shall be detoured during all phases of construction. ACCESS MANAGEMENT The Contractor shall notify the Engineer at least fourteen (14) calendar days prior to the start of the detour. If the Contractor is negligent in adhering to the established (A) The Contractor shall furnish the name and the cell phone number of the individual detour schedule, he shall be subject to a daily charge assessed at a rate of $1500.00 responsible for the access management during construction. This individual shall be “on per day for each day the detour is left inplace. call” 24 hours per day, seven days per week for the duration of the project. This information shall be made available to the business owners, property owners and rental • (B) Except for closure of the roadway in the immediate work zone, T.H. 59 and all tenants along T.H. 4 within the construction limits. The Access Manager shall local crossroads shall be kept open to local traffic at all times. If the Contractor is communicate access management/construction staging with local emergency service negligent in adhering to local traffic provisions established herein these provisions providers providing service to the project area and local businesses within the construction zone. and elsewhere all work shall be considered Unauthorized and no payment will be made. (B) The Contractor shall coordinate and hold a public pre‐construction meeting to discuss access management and construction staging. Invitees shall include business owners on • (C) The Contractor shall make every effort to minimize disruption to residents, T.H. 4 within the construction limits, local emergency services providers and the MnDOT which are adjacent to this work. Access must be maintained to residents at all Project Engineer. This meeting should be held at least 3‐6 weeks prior to the start of times. Work shall be conducted in such a manner to cause minimal interruption to construction activities in each construction year. The Contractor’s Access Manager shall resident traffic. If the Contractor is negligent in adhering to this resident access also be present at this meeting. plan, he shall be subject to a hourly charge assessed at a rate of $500.00 per hour for each hour the resident access is compromised. (C) Payment for access management activities and the Access Manager shall be incidental.
115 116 115 116
CSAH 5 –Watonwan Co. 6” Whitetopping MOT McLeod County MOT
S-7 (1404) MAINTENANCE OF TRAFFIC AND (2563) TRAFFIC CONTROL • The Contractor shall provide residents living along CSAH 5 with access to their • Local access for residences and businesses along the project must be maintained at all times homes at all times during construction. of the project. All costs for maintenance of access shall be incidental. The use of reclaim material and/or millings for traffic control or staging purposes is prohibited without prior approval of the Engineer. • Where needed, this shall involve temporarily leveling the shoulders and ditch‐ • The contractor may propose additional traffic control measures to aid in the protection of in slope to accommodate vehicles from the home site to the nearest cross freshly poured concrete. Additional traffic control measures not shown on the traffic control road and placement of temporary gravel approaches when concrete has cured plan sheet need approval from the Engineer prior to placement. No extra compensation will be provided for additional traffic control measures that are Contractor requested and Engineer sufficiently to carry cars and light duty trucks. approved.
• The Contractor shall coordinate his/her work and cooperate with the adjacent landowners along the project. This project is may require staging of the milling operations and concrete pours to maintain local access for adjacent farming activities. Staging of the milling operations or concrete pours shall be the responsibility of the Contractor and shall be incidental to the traffic control item.
117 118 117 118
What is Stringless Paving? Stringless Paving
. Alternative to conventional stringline paving. . Uses electronic guidance systems to replace pins, sensors, and “stringline.” . Electronic guidance system controls elevation and steering of the paving machine(s).
Sometimes referred to as 3D paving.
119 120 119 120
20 3/4/2021
Stringless Paving Stringless Paving
121 122 121 122
Subgrade and Aggregate Base Preparations 2301.3.D
Prepare the subgrade in accordance with 2105 or 2106, “Excavation and Embankment,” and 2112, “Subgrade Preparation”
Subgrade & Base
Gordy Bruhn
123 124 123 124
Subgrade Avoid Abrupt Changes in Subgrade Treatments
Apply 1:20 taper when tying into bridges or existing roadways. In other words… • Built to Specified Tolerances (Typical Sections) No vertical cuts, taper the subcut at a 1:20 when matching into existing roadways. • Uniform Support (Like Materials & Moisture) • Proper Compaction (Test Rolling Req’d?)
1V : 20H Taper
125 126 125 126
21 3/4/2021
1V : 20H Culvert Treatments Subgrade Uniformity
• Uniformity & Compaction are the keys to long term pavement performance
1 to 20 Taper
127 128 127 128
Types of Base Subgrade and Aggregate Base Preparations
Prepare the aggregate base in accordance with 2211, • Primarily three types used in Minnesota “Aggregate Base,” and the following: • Base Aggregates, Dense Graded • Base Aggregates, Open Graded Fine grade the aggregate base to the shape and grade shown on the plans, allowing construction of the pavement to the • New: Drainable Stable Base thickness and cross section shown on the plans. Use an approved fine grading machine mounted on crawler tracks.
Shape and maintain the shoulders to allow surface water to drain away from the pavement and off the shoulders.
129 130 129 130
Base Trimming Subgrade and Aggregate Base Preparations (2018 Spec Book) 2301.3.D
• Base should be compacted to about 1 inch higher than plan elevation to allow for future trimming operation • Complete base construction of a sufficient width outside the edge of the pavement to support the slipform paver treads • Test Roll prior to fine‐grading/trimming grade without distortion of the alignment or grade line. • Re‐compact after trimming • Check elevated string line against paving hubs
131 132 131 132
22 3/4/2021
Track Line Track Line Not Good Good
133 134 133 134
2301.3.F.1 Placement on Aggregate Base
• Maintain the base in a moist condition until placement of concrete. • Proper moisture provides the lubrication needed for proper compaction. • Holds the dust down • Aids in fine grading Surveying, Staking and Grade control
Gordy Bruhn
135 136 135 136
Surveying and Staking Surveying and Staking
• Staking and Tolerances –MnDOT Standard Plan 5‐297.115
• Paving Grades
Survey Needs: Typically, hubs every 50’ on tangent 25’ in supers and curves
137 138 137 138
23 3/4/2021
Paving Grades Paving Hubs
• Information for calculating grades can be found in the project plans: • Typical section sheets •Placed at intervals of 25 ‐ 50 feet • Cross sections •Located within 0.02 feet of true horizontal • Plan and profile sheets •Located within 0.01 feet if true vertical • Paving details •Located at high‐ and low‐profile points (vertical curves) • Storm Sewer Plan (cross slopes) • Method of operation will determine staking requirements: (Communication Req’d) • Slip‐formed • Hand‐formed.
139 140 139 140
Grade Stake Information Super Elevation Staking
• Stationing • Offset distance • Super elevated transitions will require additional staking information: • Length of transition. • Cut or fill from adjacent top edge of slab (offset method) • Full super elevation rate. • Cut or fill from projected through both edges of slab (projected grade) • Transition lath located at all beginning and at the end of all transition • Intermediate transition lath located at even % change or at each paving hub.
141 142 141 142
Paving Grades Offset vs. Projected Paving Grades Offset vs. Projected
• Two Types: • Two Types: • String line for the concrete paver is set to an Offset grade (aka form grade) • Offset grade(aka form grade) is a level transfer of elevation from the edge • String line for the Fine Grader is set to Projected grade of pavement to the offset hub. Offset grades are typically used for fixed formed paving. • Contractor will / can request hubs are set to either Cut or Fill to Edge of Slab (ES) • Very important inspectors know the difference and what the hubs are set to
143 144 143 144
24 3/4/2021
Paving Grades Offset vs. Projected Preparation Before Concrete Placement
• Two Types: • Set offset tack line and grade blue tops • Projected grade is the elevation of the edge of slab if the slab was widened • to the location of the paving hub cross slope. tack line and blue tops are set back sufficient to allow for passage of paving equipment and/or curb machine with adequate lateral support for tracks The staked Cut or Fill would be (5’ x.02) 1/10th of a foot lower than the actual edge of slab • Tack line and grade stakes are • used for both fine grading and • paving so that uniformity of • grade is accomplished
145 146 145 146
Stringline Control
• Slip‐form paving equipment such as trimmers, spreaders, pavers, curing, and texturing equipment utilize automatic sensors that run off the string Stringline line for elevation (grade) and alignment control Gordy Bruhn (line.)
147 148 147 148
Stringline Control Stringline Control
• Alignment sensing wands are located in the front and back of the equipment and are typically only set on one side of the equipment. • Elevation sensing wands are typically located on all four corners of the equipment and need to be properly tensioned for sensitivity. • Most sensing wands use a counter balance system for adjusting the tension. The inspector should check the sensing wands for proper tensioning.
149 150 149 150
25 3/4/2021
Grade Control Automatic Grade Control
• Equip the paver with automatic grade control capable • Concrete pavement is a 1 lift operation of maintaining both the elevation and longitudinal line • Grade Control is essential to obtain ride quality and pavement shown on the plans at both sides of the paver by thickness. controlling the elevation of one side and controlling the crown, or by controlling the elevation of each side • Grade Control is initially established by proper survey and layout. independently. • Paving equipment utilizes stringlines and sensors based on the survey • Use an erected string line to achieve the grade and layout. reference.
151 152 151 152
Stringline Stringline
• Tightly stretch a wire or string line set parallel to the established grade for the pavement surface to achieve • A stringline is set outside the track line and parallel to the proposed the grade reference. pavement to guide the paving equipment both horizontally and vertically. • Set the control reference and support the line at intervals to maintain the established grade and • Most paving equipment requires a stringline to be set on both sides alignment. of the pavement for maximum grade control. • When constructing concrete overlays, set and use string lines for grade control on both sides of the roadway during paving operations.
153 154 153 154
Stringline Controls Both Line and Grade Setting Stringline
• Rigid stakes • Quality line • Quality pin and wands.
• No perceptible sagging • Eyeball for staking errors • Adjust stake spacing to fit conditions
155 156 155 156
26 3/4/2021
Checking Stringline Tension
STRINGLESS
Gordy Bruhn
157 158 157 158
Stringless Inspection
• Check the Contractor probing depths • Check the pavement edge heights • Pay attention to your daily quantities
• Spot check the surface elevation of the concrete Fine Grading the Aggregate Base • No hubs needed every 50’ • Stake control points every 500’ staggered Gordy Bruhn • No tripping on stringlines
159 160 159 160
Fine Grading of Entire Aggregate Base Fine Grading
161 162 161 162
27 3/4/2021
Trimmers and Trimming Trimmers and Trimming
• A trimmer utilizes a rotary cutting head to trim the base • Trimming is the material. process of fine grading the base • During the trimming operation material to the water should be added to the base to eliminate segregation of required grade and the fine particles from the larger cross section. particles.
• After trimming the disturbed base material must be recompacted.
163 164 163 164
Trimmers and Trimming Fine Grading Critical Factors
• Sound and properly trimmed grade Trim base to specified tolerances: • Well maintained and clean equipment ◦ Enhance pavement • Proper equipment setup and machine attitude performance • Proper weight & traction ◦ Minimize concrete spread • Moist base loss • Consistent and uniform delivery of concrete ◦ Achieve slab design thickness. • Consistent and workable concrete mix ◦ Enhance rideability. • Proper vibration frequency • Sensor sensitivity Check, Check, Check! • Quality control personnel on site • Check compaction of the agg. base after fine grading 165 166 165 166
If the lane width and cross slopes are the same, use a string line stretched across elevated paving hubs to tolerance aggregate base layer
Tolerance the Aggregate Base Using Contractors Stringline
Gordy Bruhn
167 168 167 168
28 3/4/2021
Stretched string line will not work because lane widths differ. Note that the When tying on a lane or shoulder, use a 10’ straight edge to string lines are at differing elevations, Left 100.6’ –Right 100.72’ tolerance the aggregate base.
169 170 169 170
Tolerance the aggregate base using a string line Track Line
• Most pavers need 3‐4 feet beyond outside edge of pavement • Construct parallel to base cross slope • Durable for paving train • Keep it clean
171 172 171 172
Surveying Overlays –Why is it necessary?
• Determine payment for concrete • Surveying • Survey the surface after the PASSRC or HMA interlayer is placed CONSTRUCTION SURVEYING for CONCRETE OVERLAYS • Use over‐layed surface to establish new profile grades • Preliminary surveys can only be done before letting if geotextile fabric is being used for the interlayer the same year. Gordy Bruhn • After surveying –recalculate the cubic yard quantity and pay up to 102% of recalculated quantity.
173 174 173 174
29 3/4/2021
New surface grade is used to established new profile grades. Surveying Responsibilities
• Establish a new profile so the PCC pavement thickness will meet minimum design requirements. •Agency surveying •Contractor surveying, numerous projects have utilized Engineering firms for “Contractor” surveying. •Pros and Cons •We are putting together new survey language that includes both stringline and stringless options
175 176 175 176
Geotextile Fabric Interlayer
http://www.dot.state.mn.us/products/concrete/nonwovengeotextilefabricbondbreakerinterlayer.html
Installation of Geotextile Interlayer for Overlays
Gordy Bruhn
177 178 177 178
Geotextile Installation Geotextile Installation
Preferred method: Secure fabric with adhesive Another method: Secure fabric with nails • Only need to spray the edges • Designed to hold in tension • Can easily be separated for adjustments
179 180 179 180
30 3/4/2021
Geotextile Installation Geotextile Installation
Remove loose or deteriorated surfacing • Place fabric within 7 days of paving
• Do not place dowel baskets if its going to rain
• If rain event occurs, remove excess water from fabric by use of rollers or other method
181 182 181 182
Geotextile Installation TH 35 ‐ Geotextile Installation
• Keep tight without excess wrinkles or folds • Damaged fabric should be removed and replaced
• Fabric should extend beyond edge of pavement • Should terminate above, within, • Geotextile fabric strips used or adjacent to the drainage • Fabric extended 2‐3 inches outside system the bottom rungs of basket • Fabric tied into the draintile 183 184 183 184
SlipForm Advantages
• Uses low slump concrete • High quality concrete consistently consolidated • Permits high production paving Slipform Concrete Placement Process • Capable of producing a very smooth riding surface Video of Slipform Paving operation
Matt Zeller https://www.youtube.com/watch?v=8mnmmxzhYfU&list=PLWTCx1 38Tg4GoNHVSba5QVMWYrW2Nay92&index=4&t=0s
185 186 185 186
31 3/4/2021
THIS IS A SLIPFORM PAVER THIS IS NOT A SLIPFORM PAVER
187 188
187 188
Slipform Paving Extrusion Envelope
• The extrusion process utilizes vibration pressure and movement to apply energy and force the concrete through a paving mold creating a uniform shape. TO EXTRUDE: Excess Concrete Movement Strike Off Vibrator Tamper “To shape a material by Concrete Head forcing it through a mold.” Profile Pan Fluidized Concrete Side Form Resistance Batter
Profile Pan Batter - 189 Compression-Paver Uplift 190 189 190
Slipform Pavers and Paving Slipform Pavers and Paving
• Slip‐form paving is used when large amounts of concrete must be placed efficiently. • Slip‐form pavers form and consolidate fresh concrete while they travel. • Most common applications of slip‐form paving are mainline pavements and airports.
191 192 191 192
32 3/4/2021
Concrete Equipment and Paving Operations Slipform Construction Spec Spec
• Provide self‐propelled spreading and finishing machines • Place concrete using a slipform paver or combination of capable of consolidating and finishing the concrete and pavers designed to spread, consolidate, screed, and float‐ producing a dense and homogenous finished surface. finish the freshly placed concrete with minimum hand finishing. • Provide a slipform paver with a non‐oscillating extrusion plate with an adjustable angle of entry.
193 194 193 194
Belt Placers and Spreaders Belt Placers and Spreaders
• Belt placers and spreaders are used to provide a consistent head of concrete in front of the paver.
• Maintaining a constant head of concrete will help achieve a smooth ride.
195 196 195 196
Belt Placers and Spreaders Belt Placers and Spreaders
197 198 197 198
33 3/4/2021
Belt Placers and Spreaders
• Advantages • Provides uniform delivery in front of the paver. • Aids in paving startup by allowing concrete to be placed close to the paver. • Reduces risk of mix segregation. • Eliminates the risk of truck damage to the trimmed base and/or track line. • Accommodates the presetting of dowel baskets for non DBI paving operations. • Aids delivery process for staged construction.
199 200 199 200
Slipform Pavers and Paving Slipform Pavers and Paving
• Types: • 4 track and 2 track models • Auger or plow used to distribute concrete • Variable speed, hydraulically controlled internal vibrators used to consolidate concrete. • Adjustable width typically from 12‐38 feet.
201 202 201 202
Slipform Paver Vibrators Consolidation and Vibration Spec
• Full‐width vibrators shall operate between 3600 VPM and • Types: 7000 VPM in concrete • Horizontal tube • Multiple spud • The Contractor may increase the vibrator frequency as • Purpose: approved by the Engineer. Additional testing may be required • Consolidate at no expense to the Agency • Fluidize
• If the vibrator fails, suspend operations and remove unconsolidated concrete.
203 204 203 204
34 3/4/2021
Slipform Paver Vibrators Spec Slipform Paver Vibrators Spec
• Regulate the rate of progress of the vibratory equipment and • Attach vibrators to spreading or finishing equipment. the duration of the application to fully, but not excessively, vibrate the concrete.
• Do not allow vibrators to come in contact with preset dowel basket assemblies, the grade, pavement reinforcement, or side • If the forward progress of the paver stops, suspend the forms. operation of vibrators.
• Do not allow the operation of vibrators to cause separation or segregation of the mix ingredients.
205 206 205 206
Slipform Paver Vibrators Spec Vibration Monitors
• The Contractor may reduce the vibration frequency within the • Projects > 3,500 cu.yd, provide an electronic monitoring device that specified range if reducing the forward progress of the paver displays the operating frequency of each individual internal vibrator for slipform concrete pavement to avoid segregation of the concrete mix.
• Connect the power to all vibrators so that they cease when • Display the operating frequency near the operator’s controls; the machine motion is stopped. visible to the paver operator and to the Engineer
• Stop paving operations if a vibrator fails to operate within the • Provide an electronic copy containing the record of data after the range specified above. completion of the concrete paving operation. Provide vibration data daily as directed by the Engineer
207 208 207 208
Zone of Vibration Influence
209 210 209 210
35 3/4/2021
What happened?
211 212 211 212
Vibrator Streaking
• Check head above vibrators • Check materials & mixtures • Check frequency
• Check paver speed • Check vibrator positions & spacing Placing Operations
• Check for blown vibrator Matt Zeller
213 214 213 214
Slipform Construction – Sequence of Operations DELIVERY OF MATERIALS
• (Preferred) Place the concrete pavement before placing • The delivery of concrete at a consistent and uniform rate is a key curb and gutter. factor in producing a quality pavement. • If the sequence of operations includes placing the curb • Concrete pavement mixtures are transported by using dump, agitator, and gutter before the concrete pavement, submit a or ready‐mix trucks. jointing plan to the Engineer for approval before • Delivery Time = Time cement was introduced into mix to the time of placing the curb and gutter. full discharge.
215 216 215 216
36 3/4/2021
Consistency – Slipform Paving Dump Truck
• For slipform concrete pavement placement, place the concrete with a slump value that optimizes placement, except ensure the concrete does not slough or slump and is adequately consolidated and meets all other requirements of 2301, “Concrete Pavement.”
• Maintain the concrete at a uniform consistency. The Engineer will not allow an edge slump greater than ⅛ in or irregular edge alignment.
217 218 217 218
Agitator Delivery
219 220 219 220
Delivery Time Delivery of Materials
• Agitator trucks and Dump trucks: • Final ride quality is related to uniform motion. • 45 minutes • Deposit concrete to minimize segregation • Ready‐Mix trucks: • Horizontal movement of concrete in front of the paver should be kept • 90 minutes to a minimum since this may cause segregation.
221 222 221 222
37 3/4/2021
Initial Paving Operations (Contractor) Placing Concrete
• Dump or discharge concrete without causing grade • Check mix yield displacement or damage to the existing asphalt or interlayer layer. • Control workability • Repair damage to the grade in accordance with 2301.3.D, • Probe for depth “Subgrade and Aggregate Base Preparations,” existing asphalt • Adjust paver speed to concrete production or interlayer as approved by the Engineer at no additional cost to the Department. • Aim for minimal finishing • Provide protection for turning concrete trucks. • Communicate with plant operator
223 224 223 224
Damage from Turning Movement Moistening the Grade
• Maintain the grade in a moist condition until placement of concrete.
225 226 225 226
Paver Operation Placing Concrete
Operate the slipform paver with a continuous forward • Use sufficient trucks to ensure a steady forward progress of movement, and coordinate all operations of mixing, the paver. delivering, and spreading concrete to provide uniform progress with minimal stopping and starting of the paver. • If the forward movement of the paver stops for a period long enough to create a cold joint or honeycombing, construct a header joint in accordance with 2301.3.F.3, “Constructing Headers.” Constant uniform motion Constant uniform motion Constant uniform motion
227 228 227 228
38 3/4/2021
Placing Concrete on Asphalt Cooling the Surface
When placing concrete on asphalt or asphalt bond beakers, comply with the following:
1) Do not place concrete on an asphalt surface with an asphalt surface temperature greater than 120 °F [50 °C]. 2) The Engineer will allow the Contractor to apply water, whitewash of hydrated lime and water, or both to cool the asphalt surface, or other methods allowed by the Engineer. 3) Before placing concrete on a milled asphalt surface, clean the milled surface by sweeping and patch as shown on the plans in accordance with 2231, “Bituminous Surface Reconditioning,” or as directed by the Engineer.
229 230 229 230
How do we fix it? Soft Spots on a Whitetopping Project ‐ Dugout & Replaced w/ Bituminous Millings
231 232 231 232
Do we fix it? How do we fix it?
233 234 233 234
39 3/4/2021
What Happened? Placing Concrete
When placing concrete adjacent to in‐place concrete pavement, protect the following: 3 All ends of transverse joints /16 inch or wider to the satisfaction of the Engineer. The Engineer will allow sawing through the existing joint when sawing the newly placed concrete The in‐place pavement to prevent damage.
235 236 235 236
Protect the edge of the concrete Uniform grade for the trackline
237 238 237 238
Iowa Special Video Discharging
• Place directly on grade • Place with spreader • Place with belt placer
• Safety first
239 240 239 240
40 3/4/2021
241 242 241 242
A Concrete Solution Necessity
• Consistent Delivery • Consistent Quantity • Consistent Quality
• Consistent Motion
243 244 243 244
245 246 245 246
41 3/4/2021
Edge Slump Edge Slump
• Edge slump occurs when the top edge of a freshly‐ • Do not allow an edge slump of greater than 1/8 in or placed, slip‐formed concrete pavement sags down irregular edge alignment after the slab is extruded from behind the paver. • Edge slump is primarily a function of the mix consistency.
247 248 247 248
Edge Slump Edge Slumping
249 250 249 250
Factors that affect Edge Slump What happened?
• Concrete consistency • Concrete mix compatibility with placement technique • Paver adjustment and operation
• Excessive finishing • Segregation on the belt placer
251 252 251 252
42 3/4/2021
Concrete Edge Distress Safety Edge Installation on MnDOT Projects
253 254 253 254
Safety Edge Installation on MnDOT projects Safety Edge
• McLeod County specified 45° instead of 30° as Tech Memo references
255 256 255 256
Structural Rumble Strips Centerline Rumble Strips
• Sinusoidal rumble when • Placed in plastic concrete required on concrete or pavements and shall be milled • Milled in hardened with a diamond-tipped blade concrete (diamond cutting blades required)
257 258 257 258
43 3/4/2021
What Happened?
Diamond-tipped blades were not used damaging the concrete
Challenges to Placing Concrete on Narrow Roadways – TH 24 Experience
Matt Zeller
259 260 259 260
Challenge – Asphalt Thickness Control Challenge – Widening roadway
• The Contractor was told to maintain a minimum of 4” • Existing width 24 ft – Final width 28 ft asphalt after milling. • Thickened edge was tied to the existing mat with 30” bars – • Milling to a string line and paving off the same string line Needed 36” bars in some areas profile would aid in controlling the thickness. • Very labor intensive. • The super elevated curves on this project were an extreme challenge.
261 262 261 262
Challenge ‐ Concrete Thickness Control Challenge –Narrow Shoulders
• Difficult to set string line for paving.
263 264 263 264
44 3/4/2021
Success Success
• Anticipated paving one lane at a time • Anticipated paving one lane at a time • Paved Full Width –Contractor used a shuttle system to • Paved Full Width move residents in and out of pavement curing areas.
265 266 265 266
Material Testing ‐ Contractor
Process Control or Quality Control Testing (QC) ◦ Random sampling locations ◦ Materials accepted and incentives computed using QC test results, unless QV or IA testing shows nonconforming material Verification Companion Material Sampling and Testing ◦ A companion sample to the Agency’s sample ◦ The results are used as part of the QC program
Gordy Bruhn
267 268 267 268
Material Testing ‐ Agency Schedule of Materials Control
Agency Acceptance Testing • Performed on a companion sample to the Contractor’s QC sample • The Schedule of Materials Control (SMC) is used to direct how • QA is meant to verify the quality of the product, (i.e. does the materials are to be sampled. material meet the specification requirements) • Always check your project contract to verify which SMC to use. • If QA test result is nonconforming, Department notifies Contractor and investigation must take place • The 2019 SMC will correspond with all projects let using the 2018 Agency Verification Testing Spec Book. • A sample to assure compliance of the Contractor’s Quality • Included is the Concrete Special Provisions for SMC. This is a Control Program modification of the concrete sampling rates. • The results are included as part of the QA Testing Program
269 270 269 270
45 3/4/2021
Schedule of Materials Control Materials Testing For Concrete
• Testing rates are minimums • Moistures Testing • Gradation responsibilities and • All samples taken in a random manner • Unit Weight requirements vary • If any field test fails, reject the concrete, unless adjustments are made to meet based on source of • Microwave Oven requirements, then retest concrete (paving vs. • Slump • The first load of concrete must have passing air and slump results, prior to ready-mix). placement • Air Content • Concrete Temperature • Material not meeting requirements shall not knowingly be placed in the work • Flexural Strength
271 272 271 272
Air Content Factors Affecting Air Content
• AASHTO T 152 Pressure Method Increase in w/cm ratio will increase air content. Increase in slump will increase air content. Excessive mixing and/or vibration will decrease air content. • Key measure of durability for freeze Increase in concrete temperature will decrease air thaw resistance content. • Types Change in cementitious sources. Gradation of the aggregates will affect slump… • Entrapped –up to 2 percent • Increase in material passing the #100 sieve will • Entrained –small bubbles we want decrease air content. • Increase in material between the #30 and #100 sieve will increase air content.
273 274 273 274
Air Content Before Consolidation Air Content Before Consolidation
Specification 2301.3.F.6.a Contractor Testing • Test the first load of concrete at the plant • Maintain the air content of Type 3 paving concrete at the specified target of 7.0% (plus 2.0 % / minus 1.5 %) of the • 1 per 300 cu. yd. or 1 per hour, whichever results in the measured volume of the plastic concrete. lower testing. • Take samples prior to spreading • Range of 5.5% to 9.0%
275 276 275 276
46 3/4/2021
Air Content Before Consolidation Air Content After Consolidation
Agency Testing Contractor Testing • 1 Agency / Contractor correlation air test per day. • Test 1 air content per ½ day of slip form paving to establish 2461.3.G.9 Allowable Testing Tolerances an air loss correction factor (ACF)
Table 2461-28 Allowable Testing Tolerances Agency Testing Test Allowable Tolerance Air content, % volume of concrete 1.0 Average slump: • 1 correlation air test per day ≤ 4 in [100 mm] 1.0 in [25 mm] 4 in – 6 in [100 mm – 150 mm] 1.5 in [38 mm] ≥ 6 in [150 mm] 2.0 in [50 mm] Unit weight, per cu. ft [cu. m], calculated to an air-free basis 1.0 lb/cu. ft [16 kg/cu. m] Compressive strength 3,000 psi – 8,000 psi [20.6 MPa – 55.2 MPa], 500 psi [3.4 MPa] average of 3 tests Note: Consider doing an Agency correlation air test on first load of concrete at the plant. Concrete is delivered to you in bucket of a loader. 277 278 277 278
Air‐Loss Correction Factor (ACF) Air Content After Consolidation
• Air content before consolidation subtracted • Once established, apply the ACF to subsequent air tests taken by air content after consolidation = ACF before consolidation to determine the air content is greater than or equal to 4.5%.
• The ACF is intended to keep the Contractor’s air content up before consolidation to ensure we have sufficient air after consolidation.
• If ACF exceeds 2.0% take another test as soon as possible to verify/adjust for a new ACF
279 280 279 280
For example: Non‐Conforming Air Content After Consolidation (2301.3.F.5.b(3)) Testing determined: Air content before consolidation = 6.5% Air content after consolidation = 5.5% Air‐Loss Correction Factor (ACF) = 6.5% –5.5% = 1.0% • If air content after consolidation is less than 4.5%: Based on this result, your ACF is 1.0%. So in this case you are loosing 1.0% air through the paving machine.
Apply this ACF to all subsequent before consolidation air tests until you • Immediately retest and verify the ACF is correct do another air content after consolidation. • If still less than 4.5%, make adjustments to the concrete or consolidation process, test any loads that have not been discharged or adjusted at the plant and apply the ACF to determine compliance • Test every load until air content test results meet requirements • Test at least three additional trucks to ensure compliance • Perform additional testing on the hardened concrete as required by the Engineer/Concrete Engineer Before Consolidation = 6.5% After Consolidation = 5.5%
281 282 281 282
47 3/4/2021
Here is an example of Adjusted % Air after consolidation less than 4.5%. What should be done……..Immediately retest and verify ACF
283 284 283 284
Test at least three additional trucks to ensure concrete remains in If the results are still less than 4.5%, make immediate adjustments to compliance. the concrete. Test every load of concrete until meets requirements.
285 286 285 286
QC Test ‐ Low or High Air Non‐Conforming Air Content Before Consolidation (Table 2301‐14)
Contractor must: ◦ Communicate immediately ◦ React to the situation Air Content before ◦ Make plant adjustments if necessary consolidation:
7.0 percent (plus 2.0% / minus 1.5%)
287 288 287 288
48 3/4/2021
SLUMP Slump
• Measure of the consistency of concrete For slipform placement: No slump testing is required
• AASHTO T119 For fixed form placement: • Factors Affecting Slump • Contractor • Water/Cement ratio. • 1 per 300 cu. yd. and as directed by the Engineer • Air content. • Test first load each day per mix • Air and mix temperature. • Haul time. • Agency • Aggregate gradation, angularity, and surface texture. • 1 slump test per day • Admixtures
289 290 289 290
Placement Temperature (2461.3.G.2) Concrete Temperature
• AASHTO T309 • Technician records corresponding concrete temperature each time air content, slump or strength test specimen is performed/fabricated. • Important influence on concrete properties • High temps affect shrinkage and cracking
• Cold temps affect cure time and strength • Maintain concrete at a temperature from 50º to 90º F, until placement.
291 292 291 292
Super Air Meter (SAM) What Does the SAM Do?
• Measure's plastic concrete • Current pressure meters only measure the volume • Measures air system quality of air (air content), not the size of the bubbles which • Modification of existing air test is the key factor in freeze thaw durability. • Field friendly • • 8‐12 Minutes SAM can tell you the volume and the size/spacing of
• Measures total air content also the air voids.
• Frequency of testing? • Small bubbles dissolve • Procedure • Test 3 times at increased pressures • Repeat • AASHTO TP 118
293 294
49 3/4/2021
What Does the SAM Do? Spacing Factor
• For a hardened air test you have to core a sample, • If, Spacing factor ≤ .008 inch (good for freeze thaw then send it into a lab. Cut and polish sample, then durability) look at it under a microscope. Takes a few days for results • Hardened Air void test is around $550 per test, while a SAM costs around $3,000.
295 296
SAM Principle What is the SAM Number ???
• Small bubbles dissolve • SAM number: correlates with the air void size and • Inverse of bubble coming out of soda after it is opened spacing or the spacing factor. • SAM # of 0.20 correlates with a spacing factor of 0.008 (Good F‐T durability), shows a good indication of performance • DOT’s finding that SAM # of 0.25 correlates better for their mixes. • The lower the SAM # = Better Freeze thaw performance and durability of the concrete Atmospheric pressure Pressure at 45 psi Dr. Tyler Ley, Oklahoma State University
297 298
SAM Projects – 2017 to 2019 SAM # vs SAM Air Content
• Feasibility of the SAM in the Field Jacob Indihar Summer 2017 SAM 0.5 • Compare to current Pressure Meter 0.45 0.4 0.35 • Compare SAM # to Hardened Air 0.3 test 0.25 Number
0.2
• Write a ghost specification SAM 0.15 0.1 0.05 0 0123456789101112 Air Content (%) Some bad Air Content numbers but SAM number still good
299 300
50 3/4/2021
Super Air Meter SAM Principle Smarter way to measure air?
• Used on several paving projects again this past Bad summer • Equipment durability has been a concern for some • Data shows that air void system before and after
Factor paver vibrators doesn’t really change even though
Research from total air content might Oklahoma State University • MnDOT changing spec to not test after paver Spacing anymore www.Superairmeter.com Good • Potential use for testing pumped concrete before instead of after pumping
SAM Number
301 302
Summer 2021
Continue to provide SAMs to the Contractors and get more data on several projects 1. 35W & Lake Street Project 2. I‐35W MnPASS Project • Gather feedback Reinforcement Placement • Testing is for information only. • Hire summer help for SAM testing on Gordy Bruhn bridge decks and concrete pumping projects
304 303 304
Sampling Rates for Reinforcing Steel Bars Pavement Steel and Dowel Bars
• Supplemental Pavement Reinforcement • Reinforcing Steel Bars –Epoxy Coated • Tie bars • Visual check for size and grade marking and “Inspected” tag • Dowel Bars • One sample (1 bar) of each size bar for each day’s coating production • Reinforcing mesh • 3 ft sample size • Continuous reinforcement • Submit samples with copies of the Certificate of Compliance, and Certified Mill Analysis
• Dowel Bars • One dowel bar from each shipment • Submit samples with copies of the Certificate of Compliance, and Certified Mill Analysis 305 306 305 306
51 3/4/2021
Testing & Inspection Reports Reinforcing Steel and Dowel Bars Specs for Reinforcement and Dowel bars
• Requirements for reinforcement and dowels relating to acceptance and • Spec 2472, “Metal Reinforcement” certification can be found in the Materials Control Schedule • Spec 3302, “Dowel Bars”
• Storage and Protection Do not store in manner that causes corrosion or contamination Store in a way to allow visual inspection Cover if exposed to weather Protect coating from damage
307 308 307 308
Repair of Damaged Epoxy Coated Concrete Improper Field Storage Reinforcement
• Repair • Epoxy Coated Bars shall be repaired when damage is in excess of ¼ x ¼ inch and the sum of all damaged areas in each 1 ft length does not exceed 2% of bar surface area
309 310 309 310
Handling Epoxy Coated Reinforcement and Storage of Concrete Reinforcement Dowels
• • Fabrication and Handling Store above ground on wooden or padded supports. • Contact points are to be padded and coated bars are to be bundled in a manner • When uncovered outdoor storage time is greater than that the strapping or handling does not damage or cut the coating 60 days, the reinforcement shall be covered to protect against sunlight, salt spray and weather exposure. • Care must be taken to minimize condensation under the protective coating
311 312 311 312
52 3/4/2021
Storage of Concrete Reinforcement Supplemental Pavement Reinforcement
• Placed over utilities and culverts • Set on chairs or blocks • Ensure proper distance between reinforcing and dowels
313 314 313 314
Tapper Steel Tie Bars
• Located at longitudinal joints. • when paving multiple lanes. • Bent tie bars are typically used at longitudinal construction joints. • Verify longitudinal positioning: • Do not place tie bars across a transverse joint. The insertion of the tie bars may conflict with the insertion of the dowel bars causing the dowel bars to become misaligned.
• Place a #4 reinforcement bar 4” from and along each side of the taper 315 316 315 316
Placing Tie Bars
Three methods:
•Set on chairs •Insert in fresh concrete •Drill and Grout
Set on chairs
317 318 317 318
53 3/4/2021
Set on chairs, and fastened to the grade Mechanically inserted in the fresh concrete
319 320 319 320
Mechanically Inserted Tie Bars What happened? How can we fix it?
Longitudinal Joint Faulting‐ tie steel not installed in correct location
321 322 321 322
Placing Bent Tie Bars
323 324 323 324
54 3/4/2021
Keyway ‐ New requirements
Keyway is eliminated from the plans
Contractor’s option when: •Placing fixed formed construction •Design thickness is 10 inches or greater • Straightening the •Use of any other keyway requires the approval tie bars of the Engineer.
325 326 325 326
Fixed Form Keyway –See Standard Plan 5‐297.221
Keyway Steel was too high
• When inspecting, make sure the keyway is at least distance (D) from the surface of the concrete.
327 328 327 328
What could have caused this? What’s wrong?
Formed keyway – No steel
Formed keyway with Formed keyway with
Consolidation Issues 329 edge slump > 1/8 in 330 329 330
55 3/4/2021
Drilled Tie Bars
• When tie bars are used in existing concrete they are known as drilled tie bars and are typically #4 or #5 deformed bar, 18‐inches long, and spaced 30 inches center to center
331 332 331 332
What Happened? Drilled Dowel Bars
• Drill and grout 18” long dowel bars, spaced 12” on center at a depth of T/2 +/‐ 1” • Use a MnDOT approved epoxy or non‐shrink grout in accordance with the Manufacturers recommendations • See Standard Plan 5‐297.221, page 4 of 4, Construction Headers
Drilled reinforcing bars too soon 333 334 333 334
Dowel Bar Basket placement
What went wrong? Rob Golish
335 336 335 336
56 3/4/2021
Placing Dowel Bars QC Plan for Anchoring Baskets
Two methods: • Provide a Quality Control Plan in writing to the Engineer for acceptance that provides a method for keeping the dowel basket assemblies anchored to the existing asphalt or interlayer and into the underlying concrete. • Basket assemblies • Dowel bar inserters (rarely used in MN) • Include the following at a minimum:
337 338 337 338
QC Plan for Anchoring Baskets Why is a QC Plan Needed?
1) Proposed type and number of fasteners 2) Proposed installation equipment 3) Dowel basket assembly anchoring plan (i.e. Anchored all basket assemblies prior to concrete placement, one lane at a time, anchor all basket assemblies during the concrete placement operation, etc.) Milled Aged 4) Action plan if mis‐aligned baskets are identified during concrete New Patching Asphalt pavement placement
339 340 339 340
Dowel Bar Basket Placement How Many Dowel Bars?
• For UBOL or Whitetopping projects • Old standard –the first dowel bar should be 6" from the pavement • Can use a set of 8 wheel path dowels in a full dowel bar basket centerline • For New/Reconstruction PCC Pavements “Wheel Path” dowels • New standard –the first dowel bar should be 12" from the pavement • Use a full‐set of 11 dowels in a full dowel bar basket centerline. • Acceptable for cities and counties to use: • Applies to all lane widths. • Only 3 dowels in each wheel path • 3 dowels in the outer wheel paths in 2‐ lane roadways
• MnDOT recommends using a full basket instead of using 2 mini baskets in a single lane
341 342 341 342
57 3/4/2021
Dowel Bar Placement and Joint Dowel Bar Assembly Standard Plate 1103K Construction Tolerances
• Construct all joints perpendicular to the grade. • Dowels should be: • Place dowel bars parallel to the grade and parallel to the centerline of the pavement. • Horizontal and parallel from each other and perpendicular to the basket +/‐ 1/8 inch per lineal foot • On center +/‐ 1/2 inch • Placed at mid depth of slab +/‐ ½ inch
343 344 343 344
Dowel Bar Baskets Dowel Bar Baskets – Ramps/Loops
• Provide dowel bar assemblies manufactured in single • Dowels are used when pavement width is greater units for the lane widths shown on the plans than 4 feet • Secure dowel bar assemblies with a minimum of 8 • Dowels should extend across the entire ramp/loop anchors (4 on each side) to hold the dowel bars in the • Do not use more than two assembled sections in any correct position and alignment one joint for ramps, loops, and tapered sections • Secure dowel bar assemblies with a minimum of 8 anchors (4 on each side) to hold the dowel bars in the correct position and alignment
345 346 345 346
Basket Layout Anchoring Dowel Baskets
• Transverse spacing as • Fasten the baskets to the surface so that they do not specified (joint layout) move vertically or horizontally more than 1/8 inch • Aligned correctly from surface. • Type, location, number and length of anchors are dependent upon field conditions; • Before the beginning of concrete pavement placement and each day prior to beginning paving, demonstrate the fastening method to the Engineer for approval.
348 347 348
58 3/4/2021
Anchoring Baskets on Grade Dowel Basket
Correct –Fastened to bottom rail Incorrect –Fastened to top rail
• Which way is the paver moving? 349 349 350
Anchoring Dowel Baskets on Overlays Basket Problems
• Brick Ties • Clips • Bent baskets back into tolerance otherwise replace basket • Additional anchors may be needed 351 351 352
Basket Location Marking
• Durable marking • Pins • Mark both sides of the pavement!
353 353 354
59 3/4/2021
Dowel Bar Placement Dowel Bar Inserters (DBI)
• Old requirement: Coat the dowel bars with • Mechanical dowel bar inserter may be used to place a thin uniform coating of a form coating dowel bars in the pavement as approved by the material in accordance with 3902, “Form Engineer and Concrete Engineer. Coating Material” • Demonstrate to the Engineer initially and on each • New requirement: Prior to delivery to the production day, that the inserted dowel bars are project site, coat the dowel bars assembly parallel to the surface and centerline slab and are with a bond breaker material in accordance located at mid‐depth of the slab thickness. with Special Provision 3302, “Dowel Bars”. Older projects may not have this language. • Not typically used in Minnesota
355 356 355 356
DBI Operation Dowel Bar Baskets Checklist
• Dowel basket tie wires can be cut after placement. • Check for the presence of Bond Breaker Coating or Form Release • Check baskets from three perspectives • Dowels parallel to center line • Dowels are level • Basket assemblies should be parallel to and aligned with each other • Check for quality of anchoring • Verify the center of the dowel baskets are marked in the concrete for sawing https://www.youtube.com/watch?v=KPwQ4YuVMW4 357 358 357 358
What’s Wrong? What’s Wrong?
Dowels to close to longitudinal joint.
Alignment
Too many basket 12” Spacing assembly sections
359 360 359 360
60 3/4/2021
What Happened? Increased Risk for Misaligned Dowel Bars
• Concern of baskets being clipped by concrete paving equipment on 12' wide lanes
Dowel bar too high
361 362 361 362
Typical Misaligned Basket Crack
Basket damaged by dump truck beyond repair
• Remove and replace the basket 363 364 363 364
Contractor Jig Used to Install Correctly
Basket not centered on the joint
365 366 365 366
61 3/4/2021
Misaligned Dowel Bars Misaligned Dowel Bars
367 368 367 368
Recommendations for alignment tolerances issues.
There is no single recommendation for misalignment – handled on a case‐by‐case basis Determine the severity of the misalignment ◦ # of occurrences (random or single areas) Contact the Concrete Engineering Unit for recommendations which may include the following: Dowel Bar and Tie Bar Placement Testing in Plastic Concrete ◦ Monetary adjustment for future maintenance ◦ Not paying for dowel bars Rob Golish ◦ Full Depth Repairs (No partial depth repairs!!) ◦ Sawing through dowels
369 370 369 370
Dowel Bar and Tie Bar Placement Testing in Plastic Concrete Dowel Bar and Tie Bar Placement Testing in Plastic Concrete
• Specification 2301.3.J • Contractor performs testing in the Plastic concrete when using a slip form paving machine • The Contractor shall furnish a MIT‐SCAN T2 or T3 non‐destructive testing device on paving projects ≥ 3,500 cubic yards. • Not required on projects less than 3,500 cu.yds • Agency and Contractor personnel shall mutually use this non‐destructive testing device during concrete pavement construction. • Perform testing in the presence of the Engineer unless otherwise approved by the Engineer
371 372 371 372
62 3/4/2021
Dowel Bar and Tie Bar Placement Testing in Plastic Concrete Dowel Bar and Tie Bar Placement Testing in Plastic Concrete
• Locate the dowel bar baskets and tie bar steel using the required walk • Agency observations do not relieve the Contractor of the requirement bridge that spans the entire width of pavement to properly place the concrete reinforcement and dowel bars as shown in the plans.
373 374 373 374
Plastic Concrete Contractor Testing ‐ 1st Day Plastic Concrete Contractor Testing –After 1st Day
On the first day after pavement placement, verify location by: After the first day, the Engineer may allow the following reduction if the placement processes is acceptable:
• Scanning at least 7 doweled transverse joints every 1000 ft • Scanning at least 4 doweled transverse joints every 1000 ft
• • Scanning longitudinal (L1T) joint at a rate of at least 75 ft out of every 1000 Scanning longitudinal (L1T) joint at a rate of at least 25 ft out of every 1000 ft ft
375 376 375 376
Alignment Tolerances Out of Alignment Tolerance
• Dowel Bar Baskets • Dowel Bar Baskets • Verify the saw cut is centered on the dowel bars (+/‐ 3 inches) • Scan both upstream and downstream from the mis‐aligned transverse • Verify the dowels are anchored parallel to the centerline doweled joints, until at least three (3) joints are in compliance.
• Tie Bar Steel • Tie Bar Steel • Verify the appropriate number of tie bars have been placed (more than 1 • Scan both upstream and downstream from the missing or mis‐aligned tie missing per panel) bars, until at least three (3) consecutive panels are in compliance. • Verify the saw cut is centered on the tie bar (+/‐ 5 inches)
377 378 377 378
63 3/4/2021
Recommendations for Alignment Tolerances Issues Operation of the MIT‐SCAN T2
• Guide to using the MIT‐SCAN T2 device for locating • Contact the Concrete Engineering Unit for reinforcement bars and dowel recommendations – handled on a case‐by‐case basis bar baskets can be found on the MnDOT Concrete Engineering website.
• http://www.dot.state.mn.us/m aterials/concretepavement.htm l
• Use the Thickness Texture MIT‐ SCAN T2 Workbook for determining scanning locations.
379 380 379 380
Thickness Texture MIT‐SCAN Wookbook Plan Sheets
Fill out the Workbook prior to start • Prior to start of the project, use the plan sheets to determine the beginning and end stations of of the project. each lane for each pavement thickness. • Enter these stations in the Thickness, Texture and MIT-SCAN T2 Report. Go to: http://www.dot.state.mn.us/materials/concretedocs/T hickness_Texture_MIT‐SCAN_Workbook_10‐12‐ 20.xlsm
381 382 381 382
Locating Reinforcing and Dowel Bar Baskets in Plastic Concrete
Immediately after Paver Concrete in Plastic Form
Hover the Device over the Concrete 383 384 383 384
64 3/4/2021
Locating Tie Bars and Dowel Bar Baskets Locating Tie Bars and Dowel Bar Baskets
Four bars shown on the display represent four sensors on the bottom of the device
Note the location of the rebar in relation to the sensor.
385 386 385 386
MIT‐Scan T2 Spec
• MnDOT reserves the right to test more than the specification requirements of the Contractor. • The Concrete Unit has 8 MIT‐SCAN T2’s that can be borrowed to use on projects • Please contact us if you would like to have your own MIT‐SCAN T2 to FIXED FORM CONCRETE PAVEMENT use on the project. Matt Zeller
387 388 387 388
Forms Forms –Modern Day
• Straight and true • Depth equal to pavement thickness • Tightly lock to ends of adjacent forms • Stake with a minimum of three pins for each 10 foot section • Stable under weight or vibration of equipment • Clean and oil before use • Recycle or discard any bent, twisted or broken forms
389 390 389 390
65 3/4/2021
Typical Steel Form Hand Formed Concrete Placement Process
Form Lock • Quality control personnel and testing equipment on site. • Place concrete on a moist base.
• Check vibratory truss screed with a stringline.
• Spread concrete at a uniform depth.
• Avoid mix segregation
391 392 391 392
Consistency –Fixed Form Paving Hand Formed Concrete Placement Process
• For fixed form placement, place the concrete with a slump • Internally vibrate around all dowel basket assemblies and along all forms with no greater than the 5 inches a spud type vibrator ahead of the screeding operation • A vibratory screed should be operated with a uniform forward motion. • Keep vibrating screed moving forward • Check the slab behind the screed to verify the proper cross slope.
393 394 393 394
Fixed Form Construction Clary Screed
• Place concrete using one or more machines to spread, screed, • Strike of concrete with a clary screed unless otherwise approved by the Engineer and consolidate between previously‐set side forms. (2301.3.E.3.b) • Accomplish vibration of these areas using hand‐held or machine‐mounted internal vibrators. • Provide an adequate number and capacity of machines to perform the work at a rate equal to the concrete delivery rate.
395 396 395 396
66 3/4/2021
Rolling Screed Requires Stinger Vibrators Truss Screed
397 398 397 398
Fixed Form ‐ Vibration Fixed Form ‐ Vibration
• Use hand‐held vibrators to consolidate concrete adjacent to side forms and fixed structures. • If not using an electronic monitoring device, use a tachometer or similar device to demonstrate to the Engineer that the paving equipment vibration • Operate the hand‐held vibrators at a speed of at least 3,600 VPM [60 Hz]. meets the requirements in this section. • Do not allow the vibrator head to contact the joints, load transfer devices, reinforcement, grade, or side forms. • If the vibrator fails, suspend operations and remove unconsolidated concrete. • Continue vibration to achieve adequate consolidation, without segregation, for the full depth and width of the area placed.
399 400 399 400
Floating and Texturing Curing
401 402 401 402
67 3/4/2021
Removal of Forms
• Do not remove side forms of pavement and back forms on integrant curb earlier than 12 h after placing the concrete, unless otherwise approved by the Engineer. • Pull pins and tap lightly before removal • Remove forms without exerting shock or strain, including temperature variations, on the pavement or curb. Finishing • Check edge for honeycomb
• CURE EDGES !!!!! ‐ Apply membrane curing compound to Gordy Bruhn the edges within 30 minutes of removing the forms.
403 404 403 404
Contractor Flatwork Certification Finishing – Mechanical Equipment
• Finishing is primarily completed by • The concrete Contractor or Subcontractor must have at least two (2) the slip‐form paving equipment. people with a current ACI concrete flatwork technician or flatwork • Some contractors utilize finisher certification. mechanical finishing equipment behind the paver such as • At least one (1) of them must be onsite for all concrete pours. oscillating floats or truss floats. • If mechanical finishing is the only method to produce an “acceptably closed” surface. Corrections are needed for the concrete mix and/or paving equipment.
405 406 405 406
Finishing Pans Finishing ‐ Burlap
Finishing pans behind the paver 407 Finishing – burlap behind the paver 408 407 408
68 3/4/2021
Finishing
409 410 409 410
Urban Construction
What happened?...... Concrete was not workable, why?? Various potential causes.
412 411 411 412
Urban Construction Rounding the Edge
• Use a ⅜ in radius edging tool to finish all edges of the pavement.
413 414 413 414
69 3/4/2021
Some general guidelines to follow:
• Finishing efforts kept to a minimum • Does not need to be perfect prior to final process of brooming or turf drag. • Do not add water to the surface. • Too much paste at the surface • Too much water • Over vibration • Excessive finishing
415 416 415 416
Finishing –Too Much Paste Unacceptable methods of adding water to the surface
• Do not add water to the surface of the concrete to aid in finishing without the approval of the Engineer.
IMG_0171.MOV
417 418 417 418
Wetting of Burlap Drag Acceptable methods of adding water to the surface
Acceptable Practice Questionable Practice • The Engineer will give approval to replace evaporated surface water directly behind the paver caused by a halt in forward progress from a short‐term breakdown in equipment or supply of concrete.
• The Contractor can request approval to add water to the surface when cutting bumps or filling dips in the plastic concrete each time additional water is needed.
419 420 419 420
70 3/4/2021
Adding water to the surface The Process of Finishing:
If the Contractor adds water to the pavement surface without approval by the Engineer, the Department will • Bull float, darby or straight edge not pay water/cement or ride incentives on sections • Wait for bleed water to leave surface where the water is added and the Engineer may reject the pavement in accordance with 1512, “Unacceptable • Edging and forming of joints and Unauthorized Work.” • Float one more time to remove blemishes • Steel trowel (Fresno) the surface –NOT FOR EXTERIOR CONCRETE • Texture by brooming or turf drag
421 422 421 422
Bull Float and Straight edging Hard Steel Trowels
423 424 423 424
Straight Edge Successful Practices
• Checking the surface with a 10‐ to 20‐ft • Identify bumps and dips –overlap straightedge by 1/2 hand‐operated straightedge. • Correct bumps and dips • Check straightedges periodically for trueness. • Straight edging should overlap by one‐half the length of the straightedge to ensure that the tool removes high spots and fills low spots in the surface. • Do not move concrete with a straight edge. • Check, Check, Check!
425 426 425 426
71 3/4/2021
Straight Edge (2301.3.F Placing Concrete) Straight Edge (2301.3.Q Workmanship and Quality)
• Place concrete without any vertical surface deviations of the plastic • The Engineer may use the 10 ft. straightedge as necessary to determine any defects in the concrete when matching into the beginning and end of the project, hardened concrete. bridge approaches and decks, unless otherwise allowed by the Engineer. • When measuring the concrete using the straightedge, the Engineer will: 1) Measure the hardened concrete for surface deviations greater than 1/4 in in 10 ft. • Correct all high and low spots identified within the 10 foot straight 2) Evaluate transverse joints by centering the straightedge longitudinally across the edge. transverse joint. 3) Not lay the straightedge across a lane break with differing cross slopes. • In other words, vertical tolerance in the first and last 10 feet is zero! • THIS IS FOR HARDENED CONCRETE! • THIS IS FOR PLASTIC CONCRETE!
427 428 427 428
Straight Edge (2301.3.Q Workmanship and Quality) Workability
• • The ease of placing, consolidating, and finishing freshly mixed concrete The Engineer will require corrective work on vertical surface deviations greater than and the degree to which it resists segregation is called workability. 1/4 in within the span of the straightedge in any direction. • Factors that influence the workability of concrete are: • If the Engineer and Contractor mutually agree to not perform corrective work, the • Method and duration of transportation. Engineer will assess a monetary deduction of $1,500.00 per event per lane. • Quantity and characteristics of cementitious materials. • Concrete consistency or slump. • For corrected variations, the Engineer will accept deviations less than or equal to • Gradation, shape, and surface texture of fine and coarse aggregates. 1/4 in within the span of a 10 ft straightedge in any direction. • Air entrainment. • THIS IS FOR HARDENED CONCRETE! • Water content. • Temperature of the air and concrete. • Admixtures.
429 430 429 430
How Much Water is Enough? Surface Tearing in Concrete Pavement
• Surface Tearing • Excessive Grout
431 432 431 432
72 3/4/2021
Edge Tearing Tearing of the Mix
• Check speed of paver • Check square of paving kit to stringline • Check vibration frequency • Check draft of the pan • Check mix proportions • Check air content • Check W/C ratio
433 434 433 434
What happened? Too Much Grout on Surface
• Too much water applied to surface • Over vibration (vibration speed too high) • Machine moving too slow for vibration
Workability Issues
435 436 435 436
Rule Number 1
CONCRETE CRACKS!!! Jointing
Matt Zeller
437 438 437 438
73 3/4/2021
Jointing Why Does Concrete Crack After Placement?
Why are joints necessary? • Concrete drying shrinkage
• Concrete cracks • Changes in temperature and moisture • Ambient (contraction) • Joints force the concrete to crack where we want • Gradient (curling) • Subbase restraint (friction or bond) • First applied loads
439 440 439 440
Crack Formation
100 ft
3/8 in. Drying Shrinkage -3/8 in.
Thermal Contraction
Restraint Restraint
441 442 441 442
Natural Crack Development Natural Crack Development
• Volume loss • Temperature Gradients
• Thermal Contraction • Moisture Gradients • Thermal Cycles
• Loading
Usually occurs sometime after Usually within first 12-24 hours 12 hours and may take months
443 444 443 444
74 3/4/2021
What happened? Natural Crack Development
• Proper jointing provides a series of saw cuts (joints) spaced to control crack formation
445 446 445 446
Joint Topics Joint Types and Purpose
• Joint Types and Purpose • Contraction Joints • Transverse • Joint Saw Depth • Construction Joints • Joint Spacing • Transverse Headers • Longitudinal • Load Transfer (Dowels) • Expansion Joints • Intersection Orientation • Transverse • Isolation Joints • Isolate structures or pavement
447 448 447 448
Joint Load Transfer and Tie Bars Transverse Contraction Joints
• Aggregate Interlock • Doweled Transverse joints • Tie Longitudinal and Construction Joints
449 450 449 450
75 3/4/2021
Aggregate Interlock Aggregate Interlock ?
Shear between aggregate particles below the initial saw cut 451 452 451 452
Transverse Contraction Joints Transverse Contraction Joints
1 – 1½ in dia. Smooth Dowel
t/2 Doweled t
t/4 or t/3 Reservoir 1/8 – 3/8 in (typ.)
Undoweled Sealant
453 454 453 454
Isolation Joints Expansion Joints
32-38 mm dia. Expansion Smooth Dowel Cap • Expansion and contraction of concrete Doweled Isolation Joint • Failure history 25 mm max. • Current use is limited – Thickened Edge 1.2D Filler D contact the Concrete Isolation Joint 1.2D Engineering Unit if 6D to 10D specifying
Isolation Joint Manhole, Inlet Building, etc 455 456 455 456
76 3/4/2021
Expansion/Isolation Joints NEW (Coming Soon) ‐ Preformed Joint Filler (Type F Separation Material) 3702 Preformed Joint Fillers
When using preform joint fillers: • Material must be on the Approved Products list • http://www.dot.state.mn.us/products/concrete/preformedjointfillers.html • Types that may be available: 1) Type A ‐ Cork 2) Type B ‐ Self‐expanding Cork 3) Type C ‐ Sponge Rubber 4) Type D‐1 ‐ Closed‐cell Polyethylene 5) Type D‐2 ‐ Closed‐cell Polypropylene 6) Type E ‐ Bituminous Type
457 457 458
Expansion joints Expansion joints
459 460 459 460
Longitudinal Joint (sawed & butt)
Expansion Joint
461 462 461 462
77 3/4/2021
What happened? Longitudinal Joints
Clay County – Longitudinal cracking off the ends of the tie bars 463 464 463 464
What happened?
Header Construction Freeborn County – Longitudinal cracking off the Matt Zeller mini baskets
465 466 465 466
Construction Headers
• Use fresh concrete • Consolidate thoroughly • Straight edge
• Stringline • Reinforcement Bar Headers • Edge tool • Dowel Bar Headers • See Standard Plan 5‐297.221 • Texture and cure timely
467 468 467 468
78 3/4/2021
Constructing Headers Reinforcement Bar Construction Header
• Headers: • Construct construction headers, temporary headers, and permanent headers • Located as close as possible to the middle of as shown on the plans. a panel. • Do not allow incorporating any concrete accumulated in the grout box of the • When t < 10 ½”, No. 4 bar, 30 inches long, paver into the pavement. Construct all headers such that the concrete spaced 12 inches C‐C contained in the grout box is removed from the project. Use any approved • When t ≥ 10 ½”, No. 5 bar, 30 inches long, construction header method as shown in the Standard Details. spaced 12 inches C‐C • Use internal vibration to consolidate the concrete along header joints before final finishing.
469 470 469 470
Dowel Basket Construction Header Construction Header
471 472 471 472
Construction Header – Drill and Grout Construction Header – Drill and Grout
Drill and grout 18” long dowel bars with a MnDOT approved Drill and grout with a MnDOT approved epoxy or non‐shrink epoxy or non‐shrink grout grout 473 474 473 474
79 3/4/2021
Terminal Headers (Video) Terminal Headers
• 18” deep tapered minimum 3’ • #7 bars 5 feet long • Use the terminal header when long sections of concrete abut bituminous
• Do not use a terminal header on short sections (less than 200 feet) abutting bituminous (e.g. side streets)
475 476 475 476
Things to Ensure
• Match existing joints or cracks • Reduce/eliminate crack risks • Develop a jointing plan • Watch timing Joint Layouts • Understand joint location (make adjustments!)
Matt Zeller • Consider non‐obvious factors
477 478 477 478
Transverse Joint Depth Things to Avoid
• Saw depth T/3 for all concrete (previously T/3:Overlays & T/4:Grade) • Slabs < 3 ft. wide • Tape Inserts not allowed • Slabs > 15 ft. wide • Sawing required • Angles < 60º (<90º is better)
• Include ‘Stopper Bars’ if acute angles are formed or if terminating a joint at another slab without isolation material
479 480 479 480
80 3/4/2021
Intersection Jointing ACPA Jointing Publications
• Develop a Jointing Plan • Bird’s eye view • Follow ACPA’s method • Be practical!
481 IS006P TB019P 482 481 482
C
B 0.5 m 0.5 A- 1.0 m ?
Taper Return
Circumference Return? ?
? A Telescoping manhole
StepStep 10 968123574
483 484 483 484
485 486 485 486
81 3/4/2021
I-35W & TH 62 "Unweave the Weave", South
487 488 487 488
In‐Pavement Objects
Square Inlet (no boxout)
Round Inlet Boxout
489 490 489 490
Catch basins
491 492 491 492
82 3/4/2021
Boxing Out Manholes
Square Diagonal Circular Square with Fillets
Isolation Isolation joint joint Isolation Isolation joint joint
Mid-Panel (preferred)
Wrap with Rebar 493 494 493 494
Locate in Mid‐Panel
Wrap with reinforcing steel to hold any cracks tight
Wrap with Rebar
495 496 495 496
497 498 497 498
83 3/4/2021
Good Practice Manhole construction
499 500 499 500
Construction of Local Roads Concrete Intersections
•Easier than boxouts Telescoping Manholes Construction Phasing Options
•No jointing ‐ moves •Complete closure with detours with pavement • Partial closure with detour •Set about 10 mm low & pull up after paving •Complete closure during time windows •Neenah Types: • Construction under traffic • R‐1672 • R‐1673, R‐1673‐A
501 502 501 502
Concrete Intersections Concrete Intersections
Complete Closure with Detours Partial Closure with Detours
ROAD CLOSED ROAD CLOSED USE DETOUR USE DETOUR
• Clear and understandable signing • Only one-leg closed • Sign indicating when reopens • Allow traffic on major roadway
503 504 503 504
84 3/4/2021
Concrete Intersections Concrete Intersections
Complete Closure During Time-Window Construction Under Traffic - by Lane
CLOSED REOPENS 6 A.M.
• Typically 7 p.m. to 6 a.m. window • Night construction in sequences Phase 1 Phase 2 Phase 3 Phase 4 • May require temporary pavement
505 506 505 506
Concrete Intersections Curb and Gutter Joint Spacing
Spec 2531.3C Construction Under Traffic - by Quadrant • 15’ C & G joint spacing for concrete mainline –match joints • 10’ C & G joint spacing for bituminous mainline
NEED TO MATCH Phase 1 Phase 2 Phase 3 Phase 4 PAVING JOINTS
507 508 507 508
Matching joints Matching joints
509 510 509 510
85 3/4/2021
Concrete Pavement Joint Layouts 90 Degree Rule
• Add note to plan…..Joint Layouts in field may be adjusted by the Contractor with approval of the Engineer • All concrete shall meet another joint as close to a 90 degree angle as possible. See drawing below. This joint shall be a minimum of 1 foot in length, although experience indicates 3 feet minimum may be better. • Radian joints –3’ minimum to provide lateral support. For wheel loads provide taper steel in these areas also.
511 512 511 512
90 Degree Rule and Matching Joints Paving Plan Joint Layout Recommendations
• Visit a project you designed or a similar project • Up to four lanes can be tied together. • When a roadway is more than 4 lanes wide, a L3 joint is needed between 2/3, 3/2, 4/2, 3/3, or 2/4, etc. unless a special longitudinal joint using dowel bars is designed by the Concrete Engineering Unit.
513 514 513 514
Paving Plan Joint Layout Recommendations Minimize Staging
•Minimize short segments of asphalt or concrete, • More anything except flexibility = $$$ constructability and cost are issues with small segments. • More stages = more headers = more bumps •Visualize the way a project will be constructed – determine if = rougher ride = more time = more $$$ the Contractor can start on one end of the project and pave 2 • Close a few intersections or allow the lanes straight through to the other end of the project contractor to pave through with a stronger (Minimize lane width tapering or variability) mix than can get traffic back on in 48 hours
515 516 515 516
86 3/4/2021
Paving Flexibility Paving Plan Joint Layout Recommendations
•Each time a plant moves back on to a project, it • Label all joints on the concrete paving plan. takes 1 –2 days to re‐mobilize •Minimize lane widths, it takes 1 day to change the • Dimension lane widths on concrete paving plans to exclude width on a paver curb and gutter. •More lane widths = more times the paver has to be • Keep concrete paving plans uncluttered of other items broken down and reset = more time = more $$$ (topographic symbols, surveying lines, etc.) •Use of working days and flexible start dates generally = better bid prices • Use current standard plans and plates •Allows the Contractor to better fit projects into their schedule 517 518 517 518
Paving Plan Joint Layout Recommendations Paving Plan Joint Layout Recommendations
• Not necessary to draw every contraction joint on the plan • Complicated Intersections –don’t spend too much time matching all • Not necessary for every mile of the roadway, such as long sections of the joints at intersections. The with the same cross section. If there is a specific joint pattern that engineer/contractor may elect to needs to be followed, make sure it is clearly detailed. change in the field. • Add note to plan….. Joint Layouts in field may be adjusted by the Contractor with approval of the Engineer 519 520 519 520
Concrete Pavement Joint Layouts Tapers
• • Concrete shall taper down to no less than a minimum of 1 foot in the transverse Square off tapers if at all possible in direction concrete and bituminous • Eliminate or minimize acute angle panels (especially less than 60 degrees) ‐ provide • Easier to construct reinforcing steel if this not possible • Reinforcing steel ‐ In concrete pavement areas, 6 feet wide or less, place No. 4 • Better compaction of bituminous reinforcement bars 4 inches from and along each edge of a taper. • Stripe the tapers
521 522 521 522
87 3/4/2021
Tapering Concrete in Urban Areas Other Common Questions…
• Roundabouts • Dowel the truck apron or not? NO • Which joints to tie? • Maximum Joint Spacing (outside radius – 15’) • Tying a lane on to existing concrete? • Depends on the existing concrete condition and expected life? • Whether traffic is crossing joint? • What to call the joint? –E1H or L2KT Modified • What to do with overhangs? • How much overhang? • Place a tie bar over the joint and saw or not? • Concrete widening?
523 524 523 524
Isolate Circle Pave Through
525 526 525 526
What happened?
• No problems evident by overlaying 27 ft over 24 ft • Narrower pavements also possible (examples TH 212 near Olivia – 27' over 20')
527 528 527 528
88 3/4/2021
529 530 529 530
531 532 531 532
533 534 533 534
89 3/4/2021
I‐35 North of Twin Cities What do you think? “6 x 6 x 6”
535 536 535 536
What happened? What happened?
Roundabout blowup issues
537 538 537 538
Lot Determination
The Department defines a lot as all concrete pavement of a single lane added together lineally into a lot.
The Department defines a single lane in accordance with the following:
1. From the pavement edge to the adjacent longitudinal joint Pavement Texture 2. From one longitudinal joint to the next, or 3. In the absence of a longitudinal joint, between pavement edges, 4. Each ramp and loop ≤ 18 ft wide Rob Golish 5. Doweled concrete shoulder ≥ 10 ft in width
*Determine your lot and sublot locations prior to the start of the project
539 540 539 540
90 3/4/2021
Texture Test Locations Texture Testing
• Use the Thickness Texture MIT‐SCAN T2 workbook • Contractor for determining locations. • 1 per 1000 linear feet per lane of concrete pavement • Contractor supplies all materials needed to perform the testing • http://www.dot.state.mn. us/materials/concretepav ement.html • Agency • Determine texture testing locations using the Probing, Coring and Texture Spreadsheet
541 542 541 542
Texture Report Pavement Texturing
• Give the Texture Report to the Contractor. • Astroturf drag only – concrete pavements with a posted vehicle speed • The Contractor is required to perform the Sand Patch Test at these locations in > 45 mph the outside wheel path.
• Astroturf drag or Broom finish –concrete pavements with a posted vehicle speed ≤ 45 mph, edge of pavements and hand placed concrete
Carpet Drag Broom Drag
543 544 543 544
Establishing Surface Texture (Video) Establishing Surface Texture
• Pull a carpet drag longitudinally • Maintain continual contact along the pavement. between drag and surface. • Mount the drag on a bridge • When longitudinally dragging having external alignment avoid a wavy looking pattern. control. • Provide a drag as wide as the • The Contractor may use manual concrete placed without methods including brooms on the causing edge slump. edges of the pavements to prevent edge slumping or tearing.
545 546 545 546
91 3/4/2021
Artificial Turf Drag Sand Patch Test ‐ ASTM E 965‐87
• • Molded polyethylene with Contractor is required to supply the testing equipment synthetic turf blades • Solid glass spheres – Potters beads 3 • Weight as necessary to maintain • Sample container –predetermined contact internal volume of at least 25,000 mm3 mm • Spreader Tool –ice hockey puck typically used • Brushes –used to clean the surface • Wind Screen –protect from wind • Scale –12 in (305 mm) or greater
547 548 547 548
Pavement Texture Pavement Texture Depth
• Texture Spec = 1.00 mm minimum texture depth • Agency shall provide the Contractor with the random test locations prior to the start of paving • Contractor is required to complete testing and provide the test results no later than 48 hours after pavement placement
549 550 549 550
Pavement Texture
• If areas not represented by random testing appear to not meet the minimum requirements of Table 2301‐15, the Engineer reserves the right to require additional testing in those specific areas to determine compliance.
• Run additional tests at 100 ft intervals before and after the failing test location to determine the limits of any individual failing test.
551 552 551 552
92 3/4/2021
Recessed Striping Recessed Impression for Striping
• Installed in plastic concrete • Benefits • Used in several counties • Longer striping life… • Prevent joint damage from milling concrete to prep for stripe???
553 554 553 554
Lot Determination
The Department defines a lot as all concrete pavement of a single lane added together lineally into a lot.
The Department defines a single lane in accordance with the following:
1. From the pavement edge to the adjacent longitudinal joint Thickness Determination 2. From one longitudinal joint to the next, or 3. In the absence of a longitudinal joint, between pavement edges, 4. Each ramp and loop ≤ 18 ft wide Rob Golish 5. Doweled concrete shoulder ≥ 10 ft in width
*Determine your lot and sublot locations prior to the start of the project.
555 556 555 556
Pavement Thickness Coring/Probing Specification
• For Unbonded Overlays and projects less than 3,500 yd3 • Contractor Quality Control Probing (QCP) • Quality Control Probing (QCP) 1 per 1000 lineal lane ft • Probe Verification Coring (PVC) • Probe Verification Core (PVC) • Quality Acceptance Coring (QAC) 1 per every 4 probes • Quality Assurance Core (QAC) 1 random core per every 4000 lineal lane ft
557 558 557 558
93 3/4/2021
Pavement Thickness Coring/Scanning Specification
• For all other projects (New Construction, Whitetoppings, etc.) • Contractor Quality Control Scanning (QCS) • Quality Control Scanning (QCS) 1 per 1000 lineal lane ft • Scan Verification Coring SVC) • Scan Verification Core (SVC) • Quality Acceptance Coring (QAC) 1 per every 8 scans • Quality Assurance Core (QAC) 1 random core per every 8000 lineal lane ft
559 559 560
Probing, Scanning and Coring Locations Field Probing Report • Give the Field Probing Report to the Contractor. Use the Thickness Texture MIT‐SCAN T2 workbook for determining locations.
http://www.dot.state.mn. us/materials/concretepav ement.html
561 562 561 562
Base Plate Field Scanning Report • Give the Field Scanning Report to the Contractor. • The base plate must be a 30 cm diameter circular plate supplied by Kessler Soils Engineering Products, Inc. (Specification 2301.3.L.2.a)
563 564 563 564
94 3/4/2021
Base Plate Field Coring Report
• The Agency keeps the Field Core Report • Place the base plate so it is not within 1 foot of the pavement • Do not give it to the Contractor until they are ready to core edge or within 3 feet of any reinforcement of dowel bar • Fill out completely prior to submitting cores to the Materials Office baskets
565 566 565 566
Operation of the MIT‐SCAN T2 Individual Deficient Probe or Scan
• Guide to using the MIT‐SCAN • Tolerance limit for thickness is the plan thickness minus ½ T2 device for measuring the inch. thickness of the slab can be found on the MnDOT • If a probe or scan is not within that tolerance, take a core at Concrete Engineering the probe or scan location to determine if the pavement is website. deficient.
http://www.dot.state.mn.us/materials/concretedocs/Thickness_Texture_MIT‐SCAN_Workbook_2019.xlsm
567 568 567 568
Non‐Conforming Thickness Non‐Conforming Thickness
• For core thicknesses > plan thickness minus ½ in to 1 in, the • If a core is not within the plan thickness minus ½ inch Contractor may choose one of the following: tolerance: • Take exploratory cores within 10 ft on each side • Remove and replace • Take an exploratory core in the adjacent lane • Leave in place with a monetary deduction of $20 per sq. yd. • Take additional exploratory cores at 25 ft intervals until within tolerance • For core thicknesses > plan thickness minus 1 in, the Engineer in conjunction with the Concrete Engineer, will determine: Cores showing a pavement thickness of greater than • Remove and replace the plan thickness minus 1 inch, contact the Concrete • Leave in place with no pay and a monetary deduction of $20 per sq. yd. Office for a recommendation.
569 570 569 570
95 3/4/2021
Final Average Thickness What happened?
• After all coring (including exploratory coring) and scanning is completed, use all the cores and scans (that were not cored) to determine the final average thickness for each plan thickness. • If exploratory cores are taken, use the two outside cores within plan thickness minus ½ inch. • If the length of the core or scan exceeds the plan thickness plus 0.30 inch, limit the length to the plan thickness plus 0.30 inch.
Thin Pavement Section
571 572 571 572
SAWING
• Types of Saws • Conventional saws • Early entry saws • Span saws Sawing
Matt Zeller
573 574 573 574
Joint Sawing Spec Changes Conventional Saws
2301.3.N.1 Sawing Equipment • Provide wet‐cut saws for joint establishment in all concrete • Submit a Quality Control Plan to the Engineer if early entry saws are used • When using early entry saws, use saw blades and skid plates specifically designed for the coarse aggregate type used in the concrete
575 576 575 576
96 3/4/2021
Early Entry Saws Saws
577 578 577 578
Saws Saws
579 580 579 580
Span Saws Joint Sawing Spec Changes
2301.3.N.1 Joint Establishment
• Perform the initial sawing as soon as the concrete will support the joint sawing equipment without raveling and before random cracking occurs • If raveling occurs, review sawing operation and make immediate corrections to the operation • Provide one of more backup saws and an adequate supply of blades
581 582 581 582
97 3/4/2021
Joint Establishment Marking the Joint Locations
• Space contraction joints at the intervals shown on the • Before placing the concrete, mark the location on both sides of each plans, except shorten the spacing at the following to transverse joint as approved by the Engineer. provide panel lengths at least 5ft: 1) Adjacent to header joints, 2) Reinforced panels, 3) Railroad grade crossings, and 4) Free ends of pavement. • Extend transverse joints constructed in the pavement through the integrant curb. 583 584 583 584
Marking the Joint Locations Sawcut Depths Requirements
• Transfer the markings to the fresh concrete immediately after completing the • New requirement: Sawcut depth is T/3 for everything final finishing operations. • In areas of crown correction or supers, ensure the sawcut depth is correct
585 586 585 586
Measuring Sawcut Depths Sawcut Depth
CONCRETE PAVING ASSOCIATION OF MINNESOTA CONCRETE PAVING ASSOCIATION OF MINNESOTA
• Recommend checking sawcut depths daily 587 588 587 588
98 3/4/2021
Sawcut depth Sawcut Depth
CONCRETE PAVING ASSOCIATION OF MINNESOTA CONCRETE PAVING ASSOCIATION OF MINNESOTA
589 590 589 590
Sawcut Depth Initial Joint Establishment “Green Sawing”
• Provide initial joint sawing as shown on the plans. Perform the initial sawing as soon as the concrete will support the joint sawing operation without raveling and before random cracking occurs. • Immediately after completing the joint sawing, use water under nozzle pressure to remove the sawing residue from each joint and the pavement surface.
CONCRETE PAVING ASSOCIATION OF MINNESOTA
591 592 591 592
Sawing Window Sawing Window
Too Early: Sawing Too Late: • Dependent on: Raveling Window Cracking • Mix proportions • Weather conditions • Type of aggregate Restraint Stress Equals • Hardness of aggregate Concrete Strength • Urgency of the operation Minimum Strength to Avert • Excessive Saw Cut Raveling Skip sawing Concrete Strength • Hand tooling of joints allowed, but must be later sawed to plan depth
Time 593 594 593 594
99 3/4/2021
Joint Sawing (IMCP—pages 233–236) Joint Widening
• If widening is necessary, do not widen the joints to full width until the concrete is at least 24 h old, or longer if the sawing causes raveling of the concrete.
595 596 595 596
What happened? What happened?
597 598 597 598
What happened? What happened?
599 600 599 600
100 3/4/2021
Best Management Practices (BMPs)
• BMP for Concrete Washout and Concrete Washoff
Joint sealing
Matt Zeller
601 602 601 602
To seal or not to seal?
• In 2015, MnDOT reviewed approximately 10 projects with unsealed joint test sections installed between 1994 – 1999 • Cored 5 projects • In all cases where the seal was breached, the face of concrete cores looked worse than unsealed • Well sealed joints looked the best
603 604 603 604
To seal or not to seal?
De-bonded
1999
605 605 606
101 3/4/2021
If Joint Sealing Specified
• Use 3725, “Hot‐Poured, Extra‐Low Modulus, Elastic‐Type Joint and Crack Sealer,” for all joint sealing on concrete • Unless the type of sealant for contraction joints is otherwise specified in the contract. • Some projects specify –Pre‐formed joint sealant
607 608 607 608
Sampling Requirements for Sealers Promote Proper Sealant Installation
• Hot Pour Elastomeric Type • Follow manufacturer’s recommendations for sealing joints effectively • 5 lb sample from application wand, store in steel (1 gal) container • 1 per lot • Preformed Elastomeric • 6 ft sample • 1 per lot
609 610 609 610
Joint Sealing Installation Joint Sealing Installation
1) Seal joints after the Engineer inspects and approves the 5) Seal transverse integrant curb joints with the same joint joints sealer used to seal the pavement joints 2) Perform joint sealing on surface dry concrete after 6) Seal joints in accordance with the tolerances shown on the cleaning the joints of debris, dirt, dust, and other foreign plans matter, including accumulations of concrete 7) Provide backer rod material compatible with the sealer as 3) Lightly sandblast the joint walls before final compressed shown on the plans air cleaning 8) Remove and replace sealer at joints filled above the 4) Immediately before sealing the joints, clean the joints with permissible level shown on the plans at no additional cost a jet of compressed air under pressure of at least 85 psi to the Department.
611 612 611 612
102 3/4/2021
Joint Preparation and Cleanliness Sealing Final Thoughts
• Least costly procedure related to joint and crack • If sealing is required –let’s do it right! sealing • Take the time necessary to get an effective • Often the most under joint sealant –it will definitely be worth it for applied and omitted part of the process. the future life of the concrete pavement! • (MJZ editorial “if you believe sealing adds to the • (From Seal‐No‐Seal Website) life of the pavement”)
613 614 613 614
Curing
• Curing is the maintenance of adequate moisture and temperature in freshly placed concrete for a period of time.
Curing and Protection
Gordy Bruhn
615 616 615 616
Curing Importance of Concrete Curing
• Critical for low w/c ratio concrete • Probably the most ignored process of concrete construction • Mn/DOT Specs require blanket cure or membrane cure • Membrane cure requires poly‐alpha‐methyl styrene (AMS) Rapid loss of water through evaporation causes concrete on the • 5 to 10 TIMES (not %) less water loss at 1 and 3 surface to shrink. If shrinkage is restrained, tension develops, which days according to MnDOT lab tests
may cause cracking. 617 617 618
103 3/4/2021
White Cure can Hold Heat? Effect of Adequate Curing on Hardened Concrete
Increased: • Strength • Water tightness (Less Permeable) • Abrasion resistance • Freeze‐thaw resistance • Volume stability
619 620 619 620
Concrete Curing Requirements Curing
•Only allow approved curing compound lots/batches to be used. • Use Spec 3754 AMS or Spec 3755 Linseed Cure anytime •Check application rate of curing compound for uniformity, yield, and timely placement. year round •Visual inspection –Only take samples if material looks defective. • Cure ‐ Spec 3753 ‐ Colored and Architectural Concrete, Form‐lined Retaining Walls and other by special provision or Engineer approval • Water based curing compound (clear cure with dissipating fugitive dye) • AMS based curing compound (dye or grey)
621 622 621 622
Membrane Curing Method Curing Application Rate
• Apply at a rate of 150 ft²/gal of surface curing area. • Before application, agitate the curing compound as received in the shipping • The curing container interval spacing can be verified using the container to obtain a homogenous mixture. following equation: • Protect curing compounds from freezing Curing container spacing (ft) = • Handle and apply the membrane curing compound in accordance with the application rate (ft²/gal) x cure container volume (gal) manufacturer’s recommendations. slab width including edges (ft)
• The actual application rate can be verified using the following equation:
Curing container spacing (ft) =
Exposed pavement area including edges (ft²) 623 actual volume applied (gal) 624 623 624
104 3/4/2021
Membrane Curing Equipment Membrane Curing Equipment
• Use the fully‐automatic, self‐propelled mechanical power sprayer approved by the 1) A re‐circulating bypass system that provides for continuous Engineer to apply the curing compound agitation of the reservoir material, 2) Separate filters for the hose and nozzle, 3) Check valve nozzles, 4) Multiple or adjustable nozzle system that provides for variable spray patterns, 5) A shield to control loss of material by wind action, and 6) A spray‐bar drive system that operates independently of the wheels or track drive system.
625 626 625 626
627 628 627 628
Curing Compound: Good Practice 2301.3.M Concrete Curing and Protection
After completing final finishing operations, cure all exposed concrete surfaces. • Place the membrane curing compound within 30 minutes: Of concrete placement or once the bleed water has dissipated, unless the Engineer directs otherwise. after permanent removal of the forms or curing blankets, unless the contract requires otherwise.
Equal to a white sheet of typing paper 629 630 629 630
105 3/4/2021
Curing Blanket Method Curing Compound: Good Practice
• After completion of the finishing operations and without marring the concrete, cover the concrete with curing blankets. • Install in a manner that envelops the exposed concrete and prevents loss of water vapor. • After the concrete has cured, apply membrane curing compound to the concrete surfaces that will remain exposed in the completed work. Note the
631 edge! 632 631 632
Curing Compound: OK Practice Curing Compound: Poor Practice
NOT ALLOWED
633 634 633 634
Damaged or Unsatisfactory Membrane Concrete Curing and Protection Curing Application
• If the curing compound is damaged during the curing • Whenever weather conditions are such as to cause period, immediately repair the damaged area by re‐ unusual or adverse placing and finishing conditions or spraying. equipment failures occur, expedite the application of a curing method or temporarily suspend the mixing and placing operations, as the conditions require. • If the Engineer determines that the initial or corrective spraying result in unsatisfactory curing, the • Engineer may require the Contractor to use the If necessary, to remove the coverings to saw joints or perform other required work, and if the Engineer blanket curing method, at no additional cost to the approves, remove the covering for the minimum time Department. required to complete that work.
635 636 635 636
106 3/4/2021
Concrete Curing and Protection What happened?
• Failure to comply will result in the Engineer, in conjunction with the Concrete Engineer, applying a monetary deduction in accordance with 1503, “Conformity with Contract Documents.”
• When there is not a separate contract unit price for Structural Concrete, the Department will apply a monetary deduction of $30.00 per cu. yd [$39.00 per cu. m] or 50 percent of the Contractor‐provided invoice amount for the concrete in question, whichever is less.
Cured too soon? too late? 637 638 637 638
Protection Against Rain
• Protect the concrete from damage due to rain. Have available, near the site of the work, materials for protection of the edges and surface of concrete. Should any damage result, the Engineer will suspend operations until the Contractor takes corrective action and may subject the rain‐damaged concrete to 1503 and 1512. RAINFALL PROTECTION
Gordy Bruhn
639 640 639 640
Preparation Rain and Preventing Damage
• Knowledgeable of weather forecast • Begin covering at first signs of rain • Plastic sheeting on site • Stop production and paving and begin protecting work. • Steel forms or wooden boards available on site • Cover back to the point where rain is not indenting surface, starting at paver and working backwards. • Rain may wash curing compound off and not damage surface (re‐cure when rain stops) • Watch for running water along edge of slab
641 642 641 642
107 3/4/2021
Edge erosion of freshly‐placed slab due to rain
• Marring of the pavement surface due to plastic sheeting. • Does not require remediation unless ride or skid resistance is unduly affected.
643 644 643 644
Correcting Damage Protection Against Rain
Do not finish rain water into the concrete surface this will reduce the • Contact the Concrete Office and we can help determine what corrective durability of the surface. measures need to be taken. After rain has stopped covers can be removed and texturing and curing can be continued. • New – If corrective work is performed to the satisfaction of the Engineer, the Severe damage with loss of mortar at the surface can be corrected Engineer will provide payment for incentives provided the concrete meets all by diamond grinding to expose good concrete and provide texture. other requirements of 2301, “Concrete Pavement.” Caution: Be aware of rapid cooling of the surface after removal of the covering this can cause cracking.
645 646 645 646
What happened? What happened? How do we fix it?
Rain damage Rain damage
647 648 647 648
108 3/4/2021
HOT WEATHER CONCRETING
• Concrete temperature can not exceeds 90 degrees F • Misting the aggregate piles • Cooling the water HOT AND COLD WEATHER PROTECTION • Pave earlier and later in the day
Gordy Bruhn
649 650 649 650
COLD WEATHER PROTECTION Cold Weather Concreting
• Concrete temperature must be 50 F or greater at time of placement • Aggregates can’t be frozen including aggregate ice chunks in pile • May heat water, aggregates or both • Can not heat cement or add chemical admixtures to prevent freezing • Do not place on frozen base or subgrade • Steals heat from the hydration process • Can freeze the concrete at the interface
651 652 651 652
Cold Weather Protection Plan Early or Late Season Concreting
• Use of fly ash If the national weather service forecast for the construction area predicts air • Temperatures during and temperatures of 36 °F or less within the next 24 hr and the Contractor wishes to after concrete placement place concrete submit a cold weather protection plan which includes the • Spring and Fall weather following: conditions • Proposed time schedule and plans for cold weather protection of concrete in • Curing writing to the Engineer for acceptance that provides provisions for adequately • Concrete Strength Gain protecting the concrete during placement and curing. • Do not place concrete until the Engineer accepts the cold weather protection plans.
653 654 653 654
109 3/4/2021
Protection Against Cold Weather Cold Weather Protection
• Protect the concrete from damage including freezing due to cold • The BOTTOM LINE ‐ Contractor is responsible for frozen concrete. weather. Should any damage result, the Engineer will suspend operations until corrective action is taken and may subject the damaged concrete to 1503 and 1512.
655 656 655 656
2301.3.M.4 Vibratory and Backfilling Protection
• Vibratory operations & backfilling may commence after 24 hours if control strength specimens have obtained a compressive strength of 2000 psi (250psi Flex) • If high early‐strength concrete is permitted, the curing period may be reduced strength specimens achieve 2000psi. Backfilling and Placing Concrete Adjacent to New Concrete
Gordy Bruhn
657 658 657 658
Vibratory Concrete Restrictions
• No vibratory equipment adjacent to the newly placed concrete for a minimum of 24 hours. • The following vibratory equipment shall be excluded after 24 hours: • Hand operated concrete consolidation equipment • Hand‐held vibratory plate compactors • Other equipment/operations may be excluded at the discretion of the Concrete Engineer Opening Pavement to Traffic
Rob Golish
659 660 659 660
110 3/4/2021
Strength and Opening to Traffic Standard (28‐Day) Strength Specimens
•Contractor will: •No strength requirements –only used to determine pavement • Cast 1 (28‐day break) Beam or Cylinder per day per opening mix, e.g., 3A21 & 3A41 •Provide curing tank •Deliver specimens to curing site, •28‐day beams are for information only – historical data used for pavement design •Place specimens in cure tank, and •Clean beam boxes
661 662 661 662
Standard (28‐Day) Strength Specimens Standard (28‐Day) Strength Specimens
•Contractor will: Agency Will: •Cure the 28‐day break beams in accordance with •Supply beam boxes, 6” x 6” x 20” beam box mold 2461.3.G.5, “Test Methods and Specimens.” •Remove beams from cure, and •Provide & Maintain curing tanks at 60º ‐ 80º F •Measure & test beams
663 664 663 664
Field Cured Strength Specimens, aka “control strength” specimens Strength Testing (Cylinders):
Contractor will: • When cylinders are used lieu of beams •Determine if field control beams or • Contractor supplies the cylinder molds cylinders are needed •Determine the number to cast for each • 4” x 8” cylinders (aggregate < 1 ¼ inch) mix • aggregate sizes greater than 1 ¼ in •Fabricate specimens, deliver to curing site, and clean beam boxes • 6” x 12” cylinders for maximum aggregate sizes greater than 1 ¼ in Agency Will: •Supply beam boxes, 6” x 6” x 20’’ beam box •Measure & test beams
665 666 665 666
111 3/4/2021
Opening Pavement to Traffic Opening of Pavement to Local Passenger Traffic (DRAFT)
• Do not open a new pavement to general public traffic or operate • The Contractor may at their own risk allow local passenger traffic (total gross vehicle paving or other heavy equipment until whichever occurs first: weight not to exceed 10,000 lbs or equivalent to a ¾ ton 6.0 L diesel pickup truck) to drive on the new pavement slab to access their residence or business after satisfactory • 7 days completion of all initial joint sawing, excluding early entry sawing, in accordance with • Concrete has reached a minimum flexural strength meeting the 2301.3N.2, “Joint Establishment.” If any damage occurs, the Engineer will evaluate the requirements of Table 2301‐15, minimum compressive strength of 3,000 concrete pavement in accordance with 2301.3.Q, “Workmanship and Quality.” psi • Prior to placement of any concrete pavement, provide a Quality Control Plan to the • If the pavement joints are widened, seal the joints before opening to Engineer for acceptance which provides the Contractor’s plan for management of local traffic. traffic during concrete pavement placement.
667 667 668
Strength Requirements for Opening is Based on Slab Thickness Testing Beams for Flexural Strength
• Engineer tests the flexural beams in accordance with 2461.3.G.5 and records results. • Record the results on the test beam spreadsheet: http://www.dot.state.mn.us/materials/concretedocs/Concrete _Test_Beam_Data.xls
• See the Concrete Manual 5‐694.522 for details on the Beam Breaker for testing flexural strength.
Cast Control specimens at the end of paving, ≤ 1 hour from time concrete • Planning on putting a video together in the near future. placement ceases.
669 670 669 670
Area Correction Factor
• The Concrete Test Beam Data spreadsheet now calculates this value
671 • The Concrete Test Beam Data spreadsheet now calculates this value 672 671 672
112 3/4/2021
Maturity Method Benefits of Using Maturity
• Reduce field control cylinders/beams • Real‐time and Continuous • Effectiveness of Cold Weather Protection Plan • Monitoring Temperature of Concrete • Form Removal • Sawing • Opening to Traffic
673 674
Development of Maturity Curve Maturity Method Contractor Required Equipment
Developing the maturity‐strength relationship requires three • Provide maturity meter or temperature sensor and data logger steps: with a secure means of collecting, measuring, recording and storing temperature data that is unalterable
Step 1 ‐ Develop the maturity‐strength curve • Provide beam or cylinder molds for development of the Step 2 ‐ Estimating the in‐place strength maturity curve and other concrete making and testing equipment Step 3 ‐ Validating the strength‐maturity relationship
675 676
Development of Maturity Curve Development of Maturity Curve Cast Strength Specimens No. of Strength Specimens Required
Table 2461‐20 Chronological Testing Ages of Strength Specimens Type of Concrete Testing Ages *
Test at least two (2) sets of strength Concrete Pavement (Spec 2301) specimens before and the remaining sets after the anticipated opening strength.
Maturity Curve can be built in Field or Embed the sensors in the center of the 2 Normal Strength Concrete (Spec 2461) 1, 3, 7, 14 and 28 days Lab additional beams or cylinders specimens High‐Early (HE) Concrete (Spec 2461) 12 hours, 1, 2, 7 and 28 days
Cure specimens in Ultra High‐Early (UHE) Concrete 3, 4 and 8 hours, 1 and 14 days a moist condition at a temp of range * The Contractor may adjust the testing ages if approved by the Engineer in conjunction 60° – 80° F with the Concrete Engineer.
677 678
113 3/4/2021
Development of Maturity Curve Development of Maturity Curve
• Strength Test specimens at time specified in 2461 • Strength test specimens at time specified in 2461
679 680
Maturity Method Maturity Equipment Provided by Contractor/Producer
Developing the maturity‐strength relationship requires three steps:
Step 1 ‐ Develop the maturity‐strength curve
Step 2 ‐ Estimating the in‐place strength Maturity Readers Step 3 ‐ Validating the strength‐maturity relationship Data Loggers
682 681 682
Development of Maturity Curve Activating temp/time recorder in the slab Placement and Frequency
Table 2461‐21 Maturity Meter or Temperature Sensor Placement and Frequency Type of Concrete Placement Frequency
Concrete Pavement
Embed about mid‐depth Place one for each day within and about 18” from edge. the last hour of placement. Full Depth Repairs Place additional sensors as Sidewalk, Driveway necessary. Entrances, Curb and Gutter Embed about 2” from the Partial Depth Repairs surface Attach to the rebar near Place at least two for each Concrete Structures the edge of exposed concrete element. surface mndot.gov 684 683 684
114 3/4/2021
Maturity Method Validate the Maturity Curve
Developing the maturity‐strength relationship requires three •The Contractor will cast 4 beams or cylinders and embed a steps: temperature sensor in 1 of the 4 specimens. •Cover with plastic immediately after casting until removal of the Step 1 ‐ Develop the maturity‐strength curve forms and then cure in a moist condition at a temp range of 60° – Step 2 ‐ Estimating the in‐place strength 80° F until they are tested. Step 3 ‐ Validate the maturity‐curve •Strength test the 3 remaining cylinders/beams as close to the maturity index (TTF) for the opening strength criteria as possible which is 3000 psi compressive strength, or 350 to 500 psi flexural strength. •Use the embedded sensor in the specimen to determine when to
strength test the 3 specimens for validation. 686 685 686
G.6.c Validate Strength‐Maturity Relationship Intervals for Validating Strength‐Maturity Relationship
• Validation Through Strength tests 1. When the maturity curve is initially developed in a laboratory, 5,000 +10% perform a validation strength test on the first day of concrete 4,500 placement.
4,000 X X -10% 2. For slipform concrete paving, perform a validation strength test at 3,500 X least once every fifteen (15) calendar days during normal plant X X 3,000 Deviation of > 10% lower than the production.
2,500 curve – develop a new curve! 3. For all other concrete, perform a validation strength test at least once every thirty (30) calendar days during normal plant 2,000 X production. 1,500
Compressive Strength (psi) Strength Compressive 1,000
500
0 0 5,000 10,000 15,000 20,000 25,000 687 Maturity (ºC-Hours) 687 688
Changes in Concrete Mixture Protect the Pavement
Perform a validation strength test if any of the following • Make sure the Contractor protects the new slab. changes occur: • Construct ramps when moving on and off the slab. (1) Change in mixture proportions greater than 5% by weight • Use protective mats when operating paving equipment. (2) Increase in the water‐cementitious materials ratio by more • Do not operate equipment wheels or tracks within 4 in of the slab edge. than 0.02 • (3) Change in the cementitious source If damage occurs, suspend operations and take corrective action. (4) Change in the class of coarse aggregate material
690 689 690
115 3/4/2021
What Happened? Does it need to be removed and replaced/repaired? How do we fix it?
Drove on fresh concrete. Grind or remove and replace. 691 692 691 692
A lack of air void spaces within the “repair” concrete placed What happened? into the tire impression
Drove on fresh concrete. Grind or remove and replace. 693 694 693 694
Is the concrete durable? What happened?
• 5 cores were tested in freeze‐thaw • 4 of the cores exhibited freeze‐thaw durable concrete • Core 5 –the contractor “patching” lost 6% of it’s mass after 300 cycles Drove on fresh concrete. Grind or remove and replace. 695 696 695 696
116 3/4/2021
Damage found to 2‐3/4” depth. Anything that ravels easily is limited to < 3/8” Is the concrete durable?
• At 300 cycles – concrete considered freeze‐thaw durable
697 698 697 698
Ride Guide
http://www.dot.state.mn.us/materials/smoothnessdocs/Ride_Guide_2‐29‐2016.docx
Smoothness
Rob Golish
699 699 700
Inertial Profiler Certification Certified IP Settings: Sample
• Inertial profilers are certified yearly at MnROAD
• Operators are certified every three years
• Certification information is available at: http://www.dot.state.mn.us/materials/profilercertification.html
2021 Inertial Profiler Decal Date: ______Serial #: ______VIN: ______Software: ______Signature: ______
MnROAD ICC SurPRO Sticker placed on each laser 702 701 702
117 3/4/2021
Various Profilers Operator Certification
http://www.dot.state.mn.us/materials/profilercertification.html MnDOT’s Pavement Surface Smoothness Specification Operator Certification • Online training course and examination: http://www.dot.state.mn.us/onlinelearning/mrr/pavementsmoothness/
• For a list of the certified inertial profiler operators go to: http://www.dot.state.mn.us/materials/smoothnessdocs/Certified_IP_Operators_1‐15‐2021.pdf
703 703 704
Smoothness Evaluation Smoothness Evaluation
There are two aspects of the IRI roughness statistic used. The first is the Table 2399-5 long‐interval roughness (Smoothness) of a 528 ft section of roadway. Smoothness Pay Adjustments and Corrective Work for Concrete Pavements Smoothness Pay Adjustment Equation in/mi $/0.1 mi International Roughness Index (IRI): • Roughness measurement that represents how the road “feels” to < 45.0 890.00 drivers and passengers.
45.0 – 85.0 2892.50 – 44.500 x Smoothness Mean Roughness Index (MRI): PCC-A • Average of left and right wheel path IRI.
> 85.0 Corrective Work to ≤ 65.0 in/mi Smoothness: • Single MRI value that represents the overall roughness of an entire 528‐foot (0.1 mile) pavement segment.
705 706 705 706
ALR Evaluation ALR Evaluation
The second is the short‐interval roughness (ALR). This approach uses a 25 ft Table 2399-7 baseline length for analysis instead of a 528 ft length. In addition, since this ALR Monetary Deductions and Corrective Work Requirements 25 ft baseline is moved across the profile data one (1) inch at a time and Corrective Work or Monetary Equation 25 ft Continuous MRI, in/mi averaged, any roughness zones will be identified. Deduction, per lineal 1.0 ft
< 175.0 Acceptable Area(s) of Localized Roughness (ALR): • 25 foot continuous MRI that equals or exceeds 175.0 in/mi. Corrective Work unless both PCC-A and a posted the Engineer and the • Replaced bumps and dips. ≥ 175.0 and < 225.0 vehicle speed > 45 mph Contractor agree to a monetary deduct of $25.00
≥ 225.0 Corrective Work
707 708 707 708
118 3/4/2021
ALR Evaluation What Part of the Specification Applies?
Table 2399-7 ALR Monetary Deductions and Corrective Work Requirements 40 50 Corrective Work or Monetary Equation 25 ft Continuous MRI, in/mi mph mph Deduction, per lineal 1.0 ft
< 225.0 Acceptable Ramps, loops, concrete intersections constructed under traffic, or any paving with a posted 10 foot Straightedge vehicle speed ≤ 45 mph ≥ 225.0 $25.00 ALR
Smoothness
709 710 709 710
Areas Excluded from Smoothness Evaluation Areas Excluded from Smoothness and ALR Evaluation (Table 2399‐2) (Table 2399‐3)
• Paving in areas with a posted vehicle speed less than or equal to 45 mph • Paving in areas with a posted vehicle speed less than or equal to 35 mph • Ramps and loops • Paving in areas with a cautionary vehicle speed less than or equal to 35 mph • Acceleration and deceleration lanes less than or equal to 1,000 ft. in length • Turn lanes, crossovers • Physically isolated segments less than 1,000 ft. in length • 10 ft on either side of obstructions in a lane that an obstruction is located • Intersections constructed under traffic – begin and end exclusion 100 ft from the intersection • Side streets, side connections radius • 150 ft before stop signs at an intersection • Doweled shoulders greater than or equal to 10 ft in width • 150 ft before yield signs at a roundabout • Bridge decks and approach panels • 20 ft from bridge decks and approach panels • 20 ft from terminal headers tying into existing pavement • Doweled shoulders less than 10 ft in width • Undoweled shoulders • Headers adjacent to colored concrete
711 712 711 712
10 ft Straightedge 2301.3.Q Workmanship and Quality
In areas excluded from Smoothness and ALR • Measure the hardened concrete for surface deviations greater than ¼ inch in The Engineer will use a 10 ft straightedge to measure for 10 ft. surface deviations in accordance with 2301, “Concrete Pavement.” • The Engineer will require corrective work on vertical surface deviations greater than ¼ inch within the span of the straightedge in any direction.
• If the Engineer and Contractor mutually agree to not perform corrective work, the Engineer will assess a monetary deduction of $1,500 per event per lane.
713 714 713 714
119 3/4/2021
Concrete – Adding Water to Surface Day of Profiling: Submittal
Profile Summary If the Contractor adds water to the pavement surface without approval of the Engineer, • Receive a printout of each pass of data from the Contractor. the Engineer will not pay any positive Pay Adjustments for 0.1 mile segments where the water was added and the Engineer may reject the pavement in accordance with 1512, • Software Version and Serial # should match those used during certification. Verify on Inertial Profiler Certificate or “Unacceptable and Unauthorized Work.” our website: http://www.dot.state.mn.us/materials/profilercertification.h tml
• IRI threshold should be set to 175.00 • IRI base length should be set at 25.00
• Low‐Pass Filter and High‐Pass Filter should be set to 0.00 or “None.”
• Check the average left and right wheel path 528‐foot IRI values. These values should be similar to Smoothness values entered into the Contractor’s Profile Summary worksheets.
715 716 715 716
Keyhole Markup Language (KML) files: geographic Day of Profiling: Submittal location data
• These files are imported into a software application called ProVAL.
• Each file must be named in the YYMMDD‐ T‐N‐D‐L‐B‐E.ERD standardized format.
Electronic data must be submitted in two formats:
1. Pavement Profile Files (PPFs): elevation data of the longitudinal profile
2. Keyhole Markup Language (KML) files: geographic location data
717 718 717 718
Day of Profiling: Submittal Upon Completion of Pavement Placement
• If the Contractor fails to submit the required data on the day of profiling, • Within 5 calendar days of pavement placement, receive ProVAL require the Contractor to reprofile all of the measured segments. summary reports containing “Smoothness Assurance” analyses.
• It is important to observe the Contractor’s profiling to ensure: • ProVAL summary reports contain Smoothness and ALR data that o Each longitudinal profile is measured only once will be entered into the Profile Summary worksheets by the o The lateral positioning of the IP is correct Contractor (once any necessary Corrective Work is completed). o The data collection speed is appropriate o The IP is run in the direction of traffic • The data in the ProVAL report is divided into four sections: 1. Analysis: Smoothness Assurance 2. Short Continuous • Contractors have been instructed to inform agency 1 2 personnel before collecting any data on a job site. 3. Long Continuous 4. Fixed Interval 3 4
719 720 719 720
120 3/4/2021
160622-TH-35-D-2-220+40-150+34
721 722
Flowchart: “What Do I Do Next?”
723 724
Identifying Smoothness Corrective Work Identifying ALR Corrective Work
The “Fixed Interval” section is examined to determine if The “Long Continuous Histogram” section is examined to Smoothness corrective work is necessary. determine if ALR corrective work is necessary. Do any Smoothness values exceed the Corrective Work Do any ALR values exceed the Corrective Work threshold threshold of 85.0 in/mi? of 175.0 in/mi or 225 in/mi?
725 726 725 726
121 3/4/2021
Before Corrective Work
• Contractor must submit a written corrective work plan to the Engineer. • Do not begin corrective work before the Engineer approves the plan.
727 728 727 728
Corrective Work After Corrective Work
• Contractor must reprofile the entire 528‐foot segment in • Receive new printouts, PPFs, and KML files for which Corrective Work was performed Corrective Work segments. • Receive updated ProVAL summary reports that contain “Smoothness Assurance” analyses for each 528‐ft segment in which Corrective Work was performed. • Receive completed Profile Summary Worksheets. • Review Profile Summary Worksheets for accuracy. • Retesting is an option, but it must be performed within 30 days of the Contractor’s data collection. • If questions arise at any time during this process, feel • Do not allow the Contractor to reprofile any other free to contact us. segments that do not contain Corrective Work
729 730 729 730
Corrective Work (Example No Corrective Work Only) Do Not Accept
• If no corrective work is required or if both the Contractor and the Engineer agree to a monetary ALR deduct. The Contractor should then use the data in the initial ProVAL report to fill out the Concrete Profile Summary worksheets.
Smoothness values exceed the • Verify the data is correct by comparing the data in the ProVAL threshold of 85.0 in/mi summary report to the Concrete Profile Summary worksheet(s).
ALR values ≥ 225.0 in/mi
Corrective Work is required • Verify that the Profile summary worksheets are filled out completely and correctly.
731 732 731 732
122 3/4/2021
No Corrective Ride Scorecard Work
2015 Mean 2016 Mean 2017 Mean 2018 Mean 2019 Mean 2020 Mean Contractor Smoothness Smoothness Smoothness Smoothness Smoothness Smoothness • No Smoothness over 85.0 in/mi A 57.8 61.2 48.2 49.0 41.9
B 46.9 43.6 40.0 45.6 43.5 48.1
C 47.7 57.8 50.9 45.9 47.9 45.7
D 65.2 62.3 46.1
E 60.1 60.4 54.5 59.0 • No ALR
F 60.1
G 55.1
H 63.4 46.0
733 734 733 734
Smoothness Incentives –are they worth it?
Defective work
Maria Masten
735 736 735 736
Defective Work Defective Work
The Department will pay for concrete pavement meeting the The Engineer will determine the limits of each individual requirements and tolerances in accordance with this section defective pavement area. If adjusting the price for defective at the contract unit price. Pavement that fails to meet the payment, the Engineer will measure the area to the nearest minimum requirements when tested in the prescribed whole square yard [square meter], except the Engineer will manner is considered defective. consider areas less than 1sq. yd [1 sq. m] as 1sq. yd [1 sq. m]. The Engineer will determine the condition of each individual The Department may reject or adjust the payment for defective area of pavement based on the calculation of defective concrete pavement in accordance with 1503, greatest deficiency within the area. “Conformity with Contract Documents,” and 1512, “Unacceptable and Unauthorized Work.”
737 738 737 738
123 3/4/2021
Random or Uncontrolled Cracking Random or Uncontrolled Cracking
• Repair or replace pavement with random or uncontrolled cracks as directed by the Engineer. • If repairing the pavement as directed by the Engineer, use a dowel bar load transfer technique in accordance with the Mn/DOT Concrete Pavement Rehabilitation Details. • Submit the intended repair technique to the Engineer for approval. • Perform pavement repairs at no additional cost to the Department. • If the repair fails, replace the pavement at no additional cost to the Department. The Engineer will accept repairs in accordance with 1516, “Acceptance.”
739 740 739 740
Non‐Conforming Materials Monetary Adjustment Considerations:
• Use your judgment • Has the contractor been conscientious to provide quality by carefully controlling materials and construction • With the help of the Concrete Engineer, consider the operations? following: • Has the contractor been proactive and made good use of • Long‐term consequences on quality and durability. QC data to maintain and improve quality? • Implications on the project's life cycle costs, service life, • Did the engineer provide the contractor with non‐ serviceability, and maintenance. conforming test results within the contractual timeframe, if specified? • Socioeconomic, environmental, and aesthetic considerations. • If timeframes are not specified, did the engineer provide non‐conforming test results in time for the contractor to • Impacts on traffic, staging, and construction timeframes. make process or materials corrections?
741 742 741 742
Monetary Adjustment Considerations:
• Upon becoming aware of a materials quality problem, has the contractor responded quickly to correct it? • Is the nonconforming test an isolated incident or a recurring situation? • How does the nonconforming test compare to the rest of the project data: • Have material test results been well within specification Plant Monitor Responsibilities requirements or consistently at the very limit of what is acceptable • How many tests are nonconforming vs. how many tests have passed Rob Golish • How far out of spec is the non‐conforming test?
743 744 743 744
124 3/4/2021
Review the Contract and Plans Contractor Organizational Chart
• Review the Contract to determine the testing • The Contractor should provide an organizational requirements for your project chart listing names and phone numbers of individuals and alternates responsible for mix design, quality control administration, and • Contact the Concrete Office if you have any inspection questions • The organizational chart should be posted in the • Schedule permitting, someone from the Concrete Contractor’s on‐site facility Office may be available to come to your project
Spec. 2301.B.1 745 746 745 746
Role of Concrete Paving Plant Monitor Paving Plant Monitor Responsibilities
When w/c incentives apply: • Review Paving Contact Report • Perform Aggregate Moisture Testing • Full‐time Agency Plant 1 Technician is required • Perform Microwave Oven Testing • Perform Aggregate Gradation Testing (or done by the lab) When w/c incentives do not apply: • Collect Aggregate Quality Testing Samples (submit to the lab for testing) • Complete the Ingredient Summary • The Agency Plant 1 Technician shall monitor as necessary to ensure compliance with the requirements of the Contract. • Incentive Calculations (may be done by Engineer)
747 748 747 748
Concrete Pavement Forms Paving Plant Monitor Responsibilities
www.dot.state.mn.us/materials/concretepavement.html Check the batch tickets multiple times per day • Is the Contractor is using correct mix design weights? • Are the batch weights adjusted in accordance with current moisture tests? • Is the w/c ratio within the specification requirements?
749 750 749 750
125 3/4/2021
Paving Plant Monitor Responsibilities Batch Plant Inspection
Walk the site!!!! • Aggregate stockpiles need to be built and maintained properly. • Monitor stockpiling and delivery of aggregates • Keep an eye on the loader operators! • Are the aggregate piles are clean?
• Know what is going on…. The main goal in aggregate stockpiling is to maintain a uniform and consistent gradation and moisture content. Loader operators should take care in the proper load out technique to avoid segregation and contamination of the aggregates.
751 752 751 752
Contaminated Stockpiles How do we fix it?
753 754 753 754
Deleterious Material What happened?
Unmixed Concrete
755 756 755 756
126 3/4/2021
We dug deeper… What did we find out?
757 758 757 758
Aggregate Stockpile Management Aggregate Stockpile Management
• Uniform Moisture • Minimize segregation • Stable and well drained foundation underneath stockpiles • Build long and wide‐NOT high! • Place a separation layer on top of soil • Build stockpiles in tiers to avoid segregation Fines at the top • Draw from areas of known moisture content • Mix the pile to create a uniform moisture
Coarse at the bottom
Picture courtesy of Martin Marietta Materials
759 760
Aggregate Stockpile Management
• Contamination On the tires • Mud balls
In the aggregate
Plant Certification
Rob Golish
Dig too deep
762 761 762
127 3/4/2021
MnDOT Requirements for Portable Concrete Plants Plant Certification
• The Contractor must perform an on‐site inspection with the Engineer who completes a “Concrete Paving Plant Contact • Contractor must provide notice 16 hours in advance of concrete paving production to perform the on‐site inspection of the concrete plant Report.”
• Obtain pre‐production samples for quality testing
Spec. 2301.B.3 763 764 763 764
Pre‐production Quality Samples Batch Plant Inspection
• Samples may be taken from the stockpile • Plant inspections ensure the batching and mixing equipment has been calibrated and in good working order.
• The ‐ #200 test may be preformed at the lab instead of at the plant at the discretion of the Engineer • A copy of the plant scale and water meter calibration certificate should be obtained for the project records.
• The actual plant inspection should be recorded in the daily project diary.
765 766 765 766
Contact Report Paving Standardized Batch Ticket
The MnDOT Certified Plant • Plant/Unit # Technician, Quality Control • Date Supervisor or Quality Manager representing the Producer • State Project Number completes and signs the report. • MnDOT Mix Number The Agency representative • Batched Time approves and signs the report. • Load Quantity
• Running total of each type of concrete, each day for each project
767 768 767 768
128 3/4/2021
Standardized Batch Ticket Combination Plant Lab –Office Requirements (2301.3.B.3.a)
• Labels identifying each material matches the mix design • The Contractor QC technicians and the Agency QA technicians share the combination plant lab - office • Cementitious and admixture abbreviations during concrete paving. • MnDOT Pit Numbers
• Target weight of materials
• Actual batched weights of materials
• Temper water
• Total water
769 770 769 770
Combination Plant Lab –Office Combination Plant Lab –Office Requirements (2301.3.B.3.a) Requirements (2301.3.B.3.a)
• Located within 100 yd from the batch plant • Electrical power supply that provides • Heating and cooling system adequate amperage for all electrical needs • Provide drinking water • Water supply connected to the sink faucet • Sample storage area to prevent contamination of the samples
771 772 771 772
Combination Plant Lab –Office Combination Plant Lab –Office Requirements (2301.3.B.3.a) Requirements (2301.3.B.3.a)
• Electronic scales of sufficient size to weigh the • 2” (50mm) sample splitter with 3 pans. samples for all required materials testing • Metal bowls of sufficient size to perform all • A four burner 30” standard electric stove top or required material testing stove and at least two additional burners • Printer with scanning and copying capabilities • Microwave oven, heat resistant glass pan, plain weave fiberglass cloth, metal scrapper and grinding pestle
773 774 773 774
129 3/4/2021
775 776 775 776
Required Equipment Required Equipment
777 778 777 778
Contact Report – Concrete Paving Plant Certification Addendum Ready Mix Paving
• Do not begin concrete paving operations until • Required for Ready Mix Plants supplying concrete to a project with an the on‐site inspection is complete, and the estimated concrete quantity ≥ 3,500 Contact Report is approved. cubic yards.
779 780 779 780
130 3/4/2021
Paving Supplied by a Certified Ready‐Mix Plant Paving Supplied by a Certified Ready‐Mix Plant
• Electrical power supply that provides adequate amperage for • Review the Ready‐Mix Contact Report on file at the plant all electrical needs • Complete the one‐page Addendum Report for Ready Mix Paving • Sink with water supply connected to the sink faucet • Paving Contact Report is for Batch Plants only • At least six (6) burners • Metal bowls of sufficient size • If w/c incentives apply provide (microwave oven, heat resistant glass pan, fiberglass cloth, metal scrapper, grinding pestle)
781 782 781 782
Paving Supplied by a Certified Ready‐Mix Plant
Contractor Mix Designs
Rob Golish Note: Additional sieves are required for concrete paving versus tradition Ready Mix concrete
783 784 783 784
Mix Design Submittal Contractor Mix Design
• Make sure the Contractor submits mix designs to the Concrete Engineering Unit for review and approval a minimum of 21 days prior to initial placement of mix design. • The Contractor can submit the mix design directly to the MnDOT Concrete Engineering Unit
785 786 785 786
131 3/4/2021
Job Mix Formula (JMF) Responsibility for Contractor‐Designed Mixes
• By signing a Contractor Mix Design, MnDOT is verifying the acceptability of the materials and compliance with the contract requirements
• MnDOT is not responsible for the performance and placement of the mix.
787 788 787 788
Contractor Mix Designs Batch Ticket Mix Design Verification
• Mix Designs are project and material specific • Ensure the correct mix design weights are being used. • MnDOT Concrete Engineering Unit will: ◦ Review and Approve Contractor’s mix design(s) ◦ Assign a JMF number ◦ Send to Project Engineer, District Materials Engineer and the Contractor ◦ Send to Metro Inspections if project is in the Metro Area
789 790 789 790
Contractor Mix Designs
2 Types of Mix Designs • 3A21 – Machine • 3A41 ‐ Handwork
Plant Sampling and Testing
Rob Golish
791 792 791 792
132 3/4/2021
Concrete Plant Batching Materials Concrete Plant Batching Materials
• Determine minimum sampling rates in accordance with the Schedule of • All materials must come from approved/qualified sources Materials Control. • Fill out the Sample I.D. cards according to the material type completely and • The most current list of approved/qualified sources can be found at enclose with lab samples. www.dot.state.mn.us/products.
793 794 793 794
Sampling of Cement, Slag and Fly Ash
• 1 sample when the plant is certified.
• Take an additional sample: • At 6 months, if producing Agency Concrete, • If the plant changes sources, or • As the Contract requires.
• The Agency provides the sealed sample container. • The Producer obtains and stores the sample. • Include the supplier's delivery invoice.
• Cementitious Sample Size: 5 lb (2 kg)
795 796 795 796
Cement Sample ID Card Fly Ash Sample ID Card (Yellow Card) (Yellow Card)
797 798 797 798
133 3/4/2021
Sampling of Admixtures Admixtures
• 1 sample when the plant is certified. • Producer/Contractor obtains all samples from dispensing tubes • Take an additional sample: • At 3 months intervals during Agency Concrete, • If the plant changes sources, or • As the Contract requires.
• The Agency provides sealed plastic container. • The Producer/Contractor obtains and stores the sample. • Include the supplier's delivery invoice.
• Admixture Sample Size: 1/2 pt
799 800 799 800
Sample ID Card (Pink Card) Use for admixture samples Sampling of Water
• 1 sample from any questionable source.
• Water Sample Size: 1 gal
• Store sample in a clean glass or plastic container.
• Fill out the pink Sample Identification Card and submit to the Materials Lab.
801 802 801 802
Production Testing Rates (SMC) Aggregate Sampling and Testing
• Perform testing in accordance with the MnDOT Concrete • Use Concrete Pavement –Concrete Plant Production testing rates Manual when: • Determine minimum testing rates in accordance with the • The entire paving project is ≥ 3,500 cu. yd. Schedule of Materials Control. • Concrete paving batch plant • Test samples randomly • Certified ready‐mix plant • All gradation samples should be taken in the presence of the Agency. • Use Certified Ready‐Mix ‐ Concrete Plant Production testing rates when: • All samples are taken off of the belts • The entire paving project is < 3,500 cu. yd. • Gradations should be mechanically sieved. • Secondary plant is used to provide minor work. 803 804 803 804
134 3/4/2021
Sampling Aggregate at a Batching Plant Sample Sizes
Sampling from a Conveyer Belt 3/4” Plus, 3/4” Minus, #7, #89, CIA, FIA, Sand #4 #67 CA-70 CA-80 CS, FS • Obtain a sample by stopping Gradation 30 lb. 10 lb. 6 lb. 500 g 500 g 500 g the belt Quality 50 lb. • Lockouts for the belts 30 lb. 20 lb. 20 lb. 20 lb. 20 lb. • Completely remove all the Moisture 2000 g 2000 g 2000 g 2000 g 500 g 500 g material in a short section -#200 5000 g 2500 g 2500 g 500 g 500 g 500 g
• When Companion samples are required, double the sample size • New 2020 –Increased gradation sample size for ¾” Plus from 25 lb to 30 lb • New 2021 – Reduced gradation and ‐#200 sample size for CIA and FIA to from 1000 g to 500 g • New 2021 – Reduced quality sample size for #7, #89, CA‐70, CA‐80, CIA, FIA, CS, FS, and sand from 30 g to 20 g 805 806 805 806
Sampling for ASR Sample ID Card (Pink Card) –ASR Testing
• 1 per paving project per sand source
• Provide one 5 lb. sample of: • 1) Cement • 2) Supplementary cementitious materials (fly ash or slag), and • 3) Sand.
• Write “Project Specific ASR Testing” on all 3 Sample ID cards.
• ASR testing is not required if the entire project is < 3,500 cu.yd.
Enter in remarks: Project Specific ASR Testing 807 808 807 808
Concrete Forms
www.dot.state.mn.us/materials/concrete/forms.html
Plant Documentation
Rob Golish
809 810 809 810
135 3/4/2021
Project Documentation and Charts Contractor Paperwork
Review the records and charts: • Provide all reports, records, and diaries to the Engineer. • Provide all batch tickets and test results to the Engineer on a • JMF Moving Average Summary (contained in the JMF Concrete Aggregate Workbook) daily basis. • • Moisture Content of Aggregates (contained in the W/C Ratio Calculation The Engineer may suspend plant operations if the Contractor Workbook) fails to provide daily test results.
• Water/Cement Ratio (contained in the W/C Ratio Calculation Workbook)
811 812 811 812
Agency Daily Diary
• Maintain a daily diary including but not limited to: • Hours of production • Equipment • Weather • Air temperatures • Contractor’s air contents at the plant Plant Incentives and Disincentives • Concrete yardage totals • W/C ratio calculations Rob Golish • Problems or unique circumstances encountered
813 814 813 814
2 Types of Concrete Paving Projects What is a concrete plant?
Incentives For concrete pavement incentives or disincentives, the Do they apply to my project? Department defines a concrete plant as the following:
(1) A primary concrete plant providing the majority of the concrete to a Aggregate Well‐Graded Project Type/Size w/c Ratio Ride paving project. Quality Aggregate (2) Only one primary concrete plant per project is allowed unless approved by the Engineer. < 3,500 cubic No No No Maybe (3) Use either a paving plant or a certified ready‐mix plant as the primary yards plant (4) The Department will only apply incentives or disincentives for materials ≥ 3,500 cubic Yes Yes Yes Maybe provided or produced by the Contractor’s primary concrete plant. yards
Incentives/disincentives apply for contracts using at least 3,500 cu. ft. of concrete.
815 816 815 816
136 3/4/2021
Incentives/Disincentives Eligibility W/C Ratio Incentives
Designed Primary Concrete Plant Eligibility for Incentives/Disincentives • W/C ratio incentives encourage the Contractor to reduce the amount of water used in their concrete mix without raising the Type of Concrete Method for Hauling w/c Aggregate Well‐graded Plant Concrete ratio*+ Quality Aggregate cement content Paving Plant Dump Trucks, Agitator Yes Yes Yes • MnDOT specifies a maximum w/c ratio of 0.40 when using Trucks, or Both cement only or fly ash and 0.42 when using slag or ternary. Certified Ready‐mix Dump Trucks, Agitator Yes Yes Yes Plant Trucks, or Both • The Contractor may remove and replace concrete with w/c Paving Plant Truck Mixers No Yes Yes ratios greater than the specified maximums. Certified Ready‐mix Truck Mixers No Yes Yes • Concrete left in place with w/c ratios greater than the Plant specified maximums will either receive a disincentive or be *High‐early mixes are not eligible for w/c ratio incentive payments. further evaluated by the Concrete Engineer. + If Contractor adds water to the pavement surface without approval by the Engineer, the Department will not pay w/c or ride incentives in those areas or may reject the pavement.
817 818 817 818
Aggregate Quality Incentives Well‐graded Aggregate
• Aggregate quality incentives are available to encourage the Contractor • Well‐graded aggregate is an optional to use a higher quality aggregate incentive to the Contractor that can:
• However, if the Contractor chooses to use marginal material, the • produce a more workable mix, Contractor may be assessed a disincentive (penalty) for using lower • reduce segregation during placement, quality aggregate • improve pumpability, and • reduce shrinkage
819 820 819 820
Producer/Contractor ‐ QC Testing
For a concrete paving batch plant: When over ≥ 250 yd3 is produced per day: ◦ 1 per 2500 yd3 per fraction per source ◦ Take initial samples for aggregate testing within the first 250 yd3 For a certified ready‐mix plant: Gradation Testing (JMF) When 20 – 400 yd3 is produced per day: ◦ 1 per fraction per source When > 400 yd3 is produced per day: Rob Golish ◦ 2 per fraction per source Specification 2301.2.L.3
821 822 821 822
137 3/4/2021
Agency ‐ QA (QC Companion Testing) Agency ‐ Gradation Verification Testing
For a concrete paving batch plant: For a concrete paving batch plant: When over ≥ 250 yd3 is produced per week: When over ≥ 250 yd3 is produced per day: ◦ 1 QA (QC Companion) sample per fraction per source per week ◦ 1 per fraction per source per day For a certified ready‐mix plant: For a certified ready‐mix plant: When ≥ 20 yd3 is produced per week: When ≥ 100 yd3 is produced per day: ◦ 1 QA (QC Companion) sample per fraction per source per week ◦ If well‐graded incentives apply: 1 per fraction per source per day ◦ If well‐graded incentives do not apply: 1 per fraction per source per week
823 824 823 824
Producer/Contractor ‐ Verification JMF Concrete Aggregate Workbook’s Companion Testing
• New –Separate JMF Concrete Aggregate Workbook’s for the Agency • Test the Verification Companion sample and Producer/Contractor
• Complete on the day the sample was completed • QC –JMF Concrete Aggregate Workbook • QA –JMF Concrete Aggregate Workbook
825 826 825 826
Producer/Contractor ‐ Gradation Testing QC –JMF Concrete Aggregate Workbook
• All gradation samples shall be taken in the presence of the Agency, • The Producer/Contractor uses the computerized QC ‐ JMF Concrete unless otherwise authorized by the Engineer. Aggregate Workbook to determine gradations in the field. • All gradation tests require companion samples. • Record the QC Gradation and Verification Companion samples in the workbook • Both are used to determine the incentive
827 828 827 828
138 3/4/2021
Found on the Well Graded mix design JMF Moving JMF Moving Gradation Procedures Test 1‐120 Incentives Ave Summary Ave Chart Band Chart
829 830 829 830
The lot number only changes if the date changes If this is a Verification Companion test, enter the Agency verification test # 831 corresponding to this test 832 831 832
QA –JMF Concrete Aggregate Workbook
• The Agency uses the computerized QA ‐ JMF Concrete Aggregate Workbook to determine gradations in the field. • Record the QA Gradation and Verification samples results in the workbook • Record the Verification Companion sample results in the workbook
Enter the Contractor gradation test results 833 834 833 834
139 3/4/2021
JMF Moving Average (2301.2.L.3.a)
• Calculate the moving average of four (4) Contractor aggregate gradation test results during production using the JMF Moving Average Summary Workbook.
• The JMF Moving Average Summary is contained in the QC ‐ JMF Concrete Aggregate Workbook.
Enter the Contractor test # corresponding to this test 835 836 835 836
JMF Moving Average Chart
The values will turn red if the gradation falls outside of the range of each sieve 837 838 837 838
JMF Adjustments (2301.2.L.3.b) JMF Adjustments
• If during production, the moving average of 4 test results of QC aggregate gradation tests falls outside the allowable JMF working range, make a JMF • If the Contractor expects a future JMF adjustment (e.g., the next adjustments within the limits specified in the Table 2301‐7 without day or beyond), they should just submit a new mix design which submitting a new mix design. will include the new JMF.
Table 2301-7 Allowable JMF Adjustments
Sieve Size Allowable Adjustment % >No. 4 ± 5 No. 8 to No. 30 ± 4 No. 50 ± 3
No. 100 ± 2 839 840 839 840
140 3/4/2021
JMF Adjustments
• The Contractor may continue paving providing the changes are documented on the JMF Adjustment Worksheet and signed by Contractor and Agency monitors
• The JMF Adjustment Worksheet needs to be submitted to the Concrete Engineer to get a new JMF number
841 842 841 842
JMF Adjustments QA Gradation Samples
• If the moving average of four tests falls outside of the already • Identify gradation samples with a “QA Gradation” on the Sample ID adjusted allowable working range, stop production and provide a Card and include the JMF number and the QC Gradation results new mix design including JMF • If Coarse Aggregate Quality Incentive/Disincentives apply:
• The Agency may also use the QA gradation sample for the Coarse Aggregate Quality incentive/disincentive testing. In this case, notify the Producer/Contractor to double the QC/QA gradation sample size
843 844 843 844
Sample ID Card (Pink Card) ‐ Gradation Agency Gradation Testing
• If the Agency is doing gradations in the field – also use the JMF Concrete Aggregate Worksheet, otherwise submit to the District lab for testing.
845 846 845 846
141 3/4/2021
Agency Verification (2301.2.L.3.c) Agency Verification
• Verify that the test results on each fraction between the Agency and Contractor are within lab‐field tolerances as shown below. • If the gradation tests on any split samples vary between the Producer and • Follow the lab‐field tolerance procedures in the Lab Manual if they are not the Agency greater than the allowable variations per Table 2301‐7, follow within lab‐field tolerance. the procedures for test result dispute resolution available from the MnDOT Table 2301-7 Lab Manual. Allowable Variations on Percent Passing Sieves • If valid, substitute the Agency test into the moving average and Sieve Size Allowed Percentage optional well‐graded incentive. 2 in – 1 in ± 8 * See Special Provisions 1 in – 3/8 in ± 6 No. 4 - No. 30 ± 4 No. 50 ± 3 No. 100 ± 2 No. 200 ± 0.6 847 848 847 848
Well‐Graded Aggregate Optional Incentive (2301.2.M.3)
• Paving Projects (3500 cy or greater)
• Use the Contractor’s combined aggregate gradation test results (QC and Verification Companion) documented in Well‐Graded Aggregate Optional Incentive the JMF Concrete Aggregate Workbook as verified by the Engineer in accordance with 2301.2.L.3.c, “Agency Verification of JMF.” Rob Golish Specification 2301.2.M.3
849 850 849 850
Well‐Graded Aggregate Optional Incentive Table 2301-13 % Retained Gradation Band Sieve Sizes % Retained 2 in 0% 1 ½ in ≤ 5% • Optional incentive: $2.00 per cu. yd 1 in ≤ 16% ¾ in ≤ 20% • The optional incentive is available to the ½ in 4 - 20% Contractor provided a concrete mixture is 3/8 in 4 - 20% No. 4 4 - 20% designed and produced meeting the No. 8 ≤ 12% requirements of Table 2301‐13: No. 16 ≤ 12% No. 30 4 - 20% No. 50 4 - 20% No. 100 ≤ 10% No. 200 ≤ 2% Coarse Sand % Retained (No.8 to No.10) > 15% 851 852 Fine Sand % Retained (No.30 to No.200) 24 - 34% 851 852
142 3/4/2021
Well‐Graded Aggregate Chart Well‐Graded Aggregate Optional Incentive
• Based on a lot representing one day’s paving
• Each Contractor’s combined aggregate gradation test results (QC and Verification Companion) is considered a sublot
• New JMF does not require new lot
• Incentives are based on Contractor’s test results as verified by Agency testing
853 854 853 854
Well‐Graded Aggregate Optional Incentive Well‐ Graded Aggregate Incentive • If the quantities produced results in no gradation testing for any given day, include the untested quantity into the next day’s production and included that quantity in the sampling rate Date tested should correspond to the lot • If the untested quantity is on the last day of production, add that number. Should not quantity to the previous day’s production have multiple dates per lot.
855 856 855 856
CY per Lot produced at the plant
Yardage per Lot placed in the field and determined by the Agency field personal per 2301.4, “Method of Measurement.” The The lot number should remain the same if the date is incentive is determined from this quantity. the same. 857 858 857 858
143 3/4/2021
‐ #200 Coarse Aggregate Testing
• Verify all Contractor fine aggregate gradations are washed to determine the percent passing the #200 sieve. • See Schedule of Materials Control for Contractor and Agency testing rates for percent passing the #200 sieve for the coarse aggregate. • Review the Contractor’s percent passing the #200 sieve Coarse Aggregate Testing on ‐ #200 sieve for the coarse aggregate results to determine compliance or if additional testing is required. • Compare to Agency results. Rob Golish Specification 3137 Spec. 3126.2.G and 3137.2.D.1
859 860 859 860
‐ #200 Coarse Aggregate Testing Producer/Contractor Testing
Maximum % passing the #200 sieve • For Class A and Class B – 1.5% • Test the first sample and then at least 1 of the • For Class C aggregate – 1.0% next 3 samples • 1 test per day thereafter Contact the Concrete Engineering Unit if • Test these samples at the plant cleanliness of coarse aggregate is a concern Percent Passing the #200 Sieve ‐ Video:
https://www.youtube.com/watch?v=dQ9EFA5_rcE&feature=youtu.be
861 862 861 862
Agency Testing ‐ #200 Coarse Aggregate Testing
Secure a representative sample of the aggregate for • Test one randomly selected sample on the first day testing. Reduce the sample obtained to a mass of production (weight) after drying of not less than: • For a concrete paving batch plant: Aggregate Size Minimum Mass • 1 test per week thereafter 3/4” Minus 2500 g (6 lb.) • For a certified ready‐mix plant: 3/4” Plus 5000 g (10 lb.) • 1 per 1000 yd3 or 1 per week, whichever results in the highest sampling rate on randomly selected samples The test sample is the end result of the reduction. thereafter Reduction to an exact predetermined mass (weight) is • Test these samples at the plant not permitted.
863 864 863 864
144 3/4/2021
‐ #200 Testing on Coarse Aggregate ‐ #200 Testing on Coarse Aggregate
The difference between the original sample weight and the washed sample weight is the loss in washing of the material passing the 75 µm (No.200) sieve.
NOTE: The sample should not leave the original pan to prevent inadvertent loss of material.
Repeat the washing process until the wash water becomes clear. 865 866 865 866
‐ #200 Testing on Coarse Aggregate
• Contractor/Producer should record all results on the JMF Concrete Aggregate Worksheet.
New: Enter the Comparison test results for percent passing #200 sieve Aggregate Quality Testing
Rob Golish Specifications 2301.2.M.1 and 3137.2.D.3
867 868 867 868
Aggregate Quality Samples Agency Testing
• Obtain aggregate quality samples on all fractions as 3 required by the Schedule of Materials Control. • 1 randomly selected test each fraction every 20,000 yd of production • There is a new Specification 3131 for intermediate aggregate (e.g., grit, buckshot, coarse sand) which may • Split the Quality sample 4 ways: be considered a coarse or fine aggregate depending on • Provide 2 quarters of the sample to the Producer/Contractor the percent passing the 1/2”, 3/8”, No.4 and No.8 • Test the ‐#200 on the Quality sample at the plant the day it was sampled sieves. • Submit the remaining sample to the lab for Quality testing including testing on the ‐#200 sieve • Test it in accordance with Specification 3131.
869 870 869 870
145 3/4/2021
Producer/Contractor Testing Aggregate Quality Samples
• Test the ‐#200 on the Quality companion sample the day it was • Fill out Aggregate Sample ID cards completely and enclose with lab sampled samples. • All other testing is at the Contractor’s discretion • Identify Quality samples with a “Q” including the specification reference (Spec 3126 for sand and 3137.2D3 for coarse aggregate) on ID card. • Record the QC and QA ‐#200 test results on the Sample ID card • Identify the Quality Companion samples with a “Q”
871 872 871 872
Aggregate Sample ID Card (Pink Card)
Coarse Aggregate Quality Testing for Incentive/Disincentive
Rob Golish Specification 2301.2.M.1
873 874 873 874
Coarse Aggregate Quality Incentive/Disincentives Coarse Aggregate Quality Incentive/Disincentives
• Includes all paving concrete (high‐early included) provided by the • Class A ‐ typically granite or gneiss aggregates Contractor’s primary paving plant. • Automatic incentive • Use the Coarse Aggregate Quality Incentive/Disincentive Workbook • Class B ‐ typically limestone aggregates to determine the random sampling locations and testing. • Tested for % absorption
• Class C ‐ typically gravel aggregates • Tested for % carbonate
• Class R ‐ Not eligible for aggregate quality incentives
875 876 875 876
146 3/4/2021
Sampling Location Agency Sampling Rates
Table 2301-9 • Class A aggregates –No sampling required Coarse Aggregate Quality Incentive/Disincentive Sampling Rate
Plan Concrete cu. yd. [cu. m] Samples per fraction (n) • Class B and C aggregates –Take samples at a location as close as possible to incorporation into the work 3,500 – 7,500 3
7,501 – 10,000 5 • Belt leading to weigh hopper is suggested location 10,001 – 25,000 10 • Split samples and leave half for Contractor/Producer 25,001 – 50,000 15
50,001 + 20
877 878 877 878
Agency Testing
Determine the random • Test the Class B aggregates for % absorption sampling locations • Test the Class C aggregates for % carbonate using the Coarse Aggregate Quality Incentive/Disincentive Worksheet
879 880 879 880
What Fractions Do You Use? Contractor/Producer Testing Rates
• If a mix contains 3 or more fractions of coarse aggregate, only the 2 fractions Test at Contractor’s discretion containing the highest % by weight are eligible for incentive
19% of 3/4”+ 33% of 3/4”- 10% of 3/8”-
881 882 881 882
147 3/4/2021
Sample ID Cards Aggregate Sample ID Card (Pink Card)
• Fill out Aggregate Sample ID cards completely and enclose with lab samples
• Identify incentive samples on the Sample ID Card with “I/D”
• Promptly submit to lab for testing
883 884 883 884
Lot Establishment Class A Aggregate Incentive/Disincentive
• The entire project is considered a single lot for each of the two fractions containing the highest percentage by • Class A aggregates (including quartzite and gneiss) weight. • Do not need to test • If the project will be constructed over multiple years and • Automatic incentive the Contractor may request payment on a yearly basis. Table 2301-10 • Contact the Concrete Office to determining Coarse Aggregate Quality Incentive/Disincentive incentive/disincentive payments on a yearly basis. Structural Concrete per cu. yd.[cu. m] QI for Fraction % Payment Change Per Fraction • If there is a change in aggregate source, a new statistical - $1.00 family should be established. Again contact the Concrete Office.
885 886 885 886
Class B Aggregate Incentive/Disincentive Class C Aggregate Incentive/Disincentive
• Class B aggregates (based on % absorption) • Class C aggregates (based on carbonate)
Table 2301-10 Table 2301-11 Coarse Aggregate Quality Incentive/Disincentive Coarse Aggregate Quality Incentive/Disincentive Structural Concrete per cu. yd.[cu. m] Structural Concrete per cu. yd.[cu. m] QI for Fraction % Payment Change Per Fraction QI for Fraction % Payment Change Per Fraction (based on % absorption) (based on % carbonate) <1.00 $1.00 < 15.0 $1.00 1.01 - 1.45 $0.50 15.1 - 24.0 $0.50 1.46 - 1.76 $0.00 24.1 - 31.0 $0.00 1.77 - 1.85 -$1.00 31.1 - 35.0 -$1.00 >1.86 As recommended by the Concrete Engineer, with coordination of the Engineer 887 > 35.1 Recommendation of State Concrete Engineer 888 887 888
148 3/4/2021
Enter the Carbonate Aggregates results in the Test Report Worksheet
889 890 889 890
Phoenix More accurate way to measure w/c ratio?
• Equipment Upgraded • Data comparable to MnDOT method • More accurate than microwave oven • Long term goals • Allow Contractor to do Phoenix ‐ Water/Cement Ratio Testing moisture testing • Modify w/c ratio specifications including Rob Golish incentive/disincentive Specification 2301.2.M.2 • Pay based on actual w/c ratio measured using the phoenix
891 891 892
MnDOT W/C Ratio Testing How do the results compare? Old Phoenix Device –w/c Testing Device
Does it average standard Time test w/cm dev concrete? Mixing water + agg moisture 0.39 0.021 30 min No Phoenix 0.41 0.030 15 min Yes Microwave 0.41 0.033 45 min Yes This is from 144 tests from two different mixtures.
• The Phoenix and Microwave consistently measure a 0.02 higher w/cm than just measuring the aggregate moisture and water gauge. • The Phoenix is faster, is more automated, and has a lower variability than the microwave test.
894 893 894
149 3/4/2021
New Phoenix Device –w/c Testing Device Summary of 2019 data
2019 Summary Average Standard Deviation The MnDOT batched method Phoenix 0.005 0.019 has the lowest variability, but Mn Method ‐0.006 0.015 it is not that different than the Microwave 0.004 0.027 Phoenix.
51 total tests
895 895 896
Summary of 2019 data Summary
• Test results show that all methods are statistically similar to the batched w/cm and to each other! • The Phoenix and microwave test are done on concrete 2019 Summary Average Standard Deviation The batched, microwave, and Phoenix Phoenix 0.011 0.017 give values that are similar and are on • The Phoenix takes less time, less labor average 0.01 higher than the MnDOT Microwave 0.010 0.020 • The Phoenix has a lower variability than the microwave method; however, this is within the Batched 0.010 0.015 noise of the tests. • The new version of the Phoenix speeds this up even more
51 total tests • The new prototype was used in 2020 paving projects • Will run more tests in 2021 • Potential implementation in 2022
897 898
Water/Cement (w/c) Ratio Spec
• Place concrete with a w/c ratio not to exceed 0.40 when using cement only or fly ash
• Place concrete with a w/c ratio not to exceed 0.42 when using slag or ternary
Water/Cement Ratio Testing • Immediate adjustments should be made when the w/c exceeds 0.40 or 0.42 • No w/c ratio incentive payments on high‐early mixes Rob Golish Specification 2301.2.M.2 • Truck mixers are not eligible for w/c ratio incentives
899 900 899 900
150 3/4/2021
Water/Cement (w/c) Ratio
• Use the W/C Ratio Calculation Workbook to determine: • aggregate moisture contents • w/c ratio • unit weight W/C Ratio Chart Tests 1-96 • microwave oven w/c ratio Procedures • charting Moisture Chart Incentives • w/c ratio incentive/disincentives
901 902 901 902
Aggregate Moisture Content Determination Initial Aggregate Moisture Testing
• Moisture content of the aggregates are used to calculate the w/c ratio • Prior to start of concrete production each day, the of the concrete Contractor/Producer should complete the initial aggregate • Verify contractor performs start‐up aggregate moisture tests moisture content testing and adjust the batch water. • Take additional moistures whenever moisture appearance of • If weather conditions allow, performing moisture testing on delivered aggregate seems to vary or batch water deviates greatly representative material at the end of production the prior from previous loads evening is allowed.
903 904 903 904
Agency Aggregate Moisture Testing Agency Aggregate Moisture Testing
If w/c incentives apply If w/c incentives apply
Paving batch plant: Certified ready‐mix plant: ◦ 1 per 1000 yd3 or completed every 4 hours, ◦ 1 per 200 yd3 or completed every 4 hours, whichever results in the higher sampling rate whichever results in the higher sampling rate ◦ Take initial samples for aggregate moisture testing ◦ Take initial samples for aggregate moisture testing within the first 250 yd3 within the first 100 yd3
Note: w/c incentives can only apply if concrete is hauled in dump/agitator trucks
905 906 905 906
151 3/4/2021
Producer/Contractor Aggregate Moisture Testing Agency Testing
If w/c incentives do not apply • Agency aggregate moisture test results are used for determining the water content to calculate Paving batch plant: the w/c ratio ◦ 1 per 1000 yd3 or completed every 4 hours, • DO NOT LEAVE SAMPLES UNATTENDED whichever results in the higher sampling rate
Certified ready‐mix plant: Aggregate Moisture Testing ‐ Video: https://www.youtube.com/watch?v=D9MBPFjuc ◦ 1 completed every 4 hours 7k&feature=youtu.be
907 908 907 908
Concrete Determination of Lots W/C Ratio • A lot represents one day’s paving Calculation • Each individual w/c ratio determination is considered a sublot Worksheet • The lot represents the cumulative average of the sublot values
• Start a new lot only if: • Mix design change due to w/c ratio exceeding 0.40 (cement only or fly ash) or 0.42 (slag or ternary) • Change from fly ash to slag or ternary, or vice versa
• A new mix design does not require new test
909 910 909 910
Determination of Lots
• If the quantities produced results in no Agency moisture testing for any given day, include the untested quantity into the next day’s production and included that quantity in the sampling rate. • Enter the project information • The lot number should not change from test to test if the date is the same • If the untested quantity is on the last day of production, • Enter the ticket number representing the batch add that quantity to the previous day’s production. tested • Enter the mix design information • Enter the batch size (will be on the batch ticket)
911 912 911 912
152 3/4/2021
Computerized Batching Report Aggregate Moisture Chart
• Review the chart to see if the aggregate moistures are consistent
Enter the absorption factor and design weight from the mix design
913 914 913 914
Aggregate Moisture Testing Batch Tickets for Determining Water and Cementitious Contents
• Upon completion of aggregate moisture testing, give moisture • Verify with the batch person when the aggregate sampled is getting results to Contractor so the batch person can enter the moisture into the concrete mix results in the batch system • It is generally 4 –10 loads after the aggregate moisture sample is taken • Periodically check the batch tickets to verify the Producer is using the correct Agency moisture contents • This is how you determine the batch ticket # representing the • Batch Plants can adjust water on each load based on the slump aggregates tested meter setting
915 916 915 916
Batch Tickets for Determining Water and Water Content Determination Cementitious Contents
• Use the 10 batch tickets surrounding the batch ticket representing • Record the water added to the mix, temper water, cement the aggregate moisture content (in this case it is ticket #31) content and fly ash content from each batch ticket.
917 918 917 918
153 3/4/2021
Table 2301‐11 Water/Cement (w/c) Ratio W/C Ratio Incentive/Disincentive
When using cement only or fly ash • The w/c ratio is calculated using the aggregate moistures, batch water, temper water, and cementitious contents W/C Test Result Payment incentive/disincentive per cu. yd
< 0.37 $3.00 0.38 $1.75 0.39 $0.50 0.40 $0.00 0.41 -$0.50 0.42 -$1.75 0.43 Determined by Concrete Engineer 919 920 919 920
Table 2301‐11 W/C Ratio Incentive/Disincentive
CY Produced at the Plant When using slag or ternary
W/C Test Result Payment incentive/disincentive per cu. yd CY Measured in the Field < 0.39 $3.00 0.40 $1.75 Date tested 0.41 $0.50 should correspond 0.42 $0.00 to the lot 0.43 -$0.50 number 0.44 -$1.75 0.45 Determined by Concrete Engineer 921 922 921 922
W/C Ratio Chart
Water Content Verification Testing (Microwave Oven Verification)
Rob Golish Specification 2301.2.M.2
923 924 923 924
154 3/4/2021
Water Content Verification Producer/Contractor Sampling
• Water content verification is determined by taking samples from the plastic concrete. • The Contractor will sample plastic concrete at the plant for Agency microwave oven testing • The water content in the plastic concrete mixture is verified by test procedure AASHTO Designation: T 318‐02 "Standard Test Method for Water Content of Freshly Mixed Concrete Using Microwave • Sample the concrete from the batch representing Oven Drying". the aggregates that were sampled for moistures
• The test must commence within 15 minutes after the water has contacted the cement.
925 926 925 926
Agency Testing Microwave Oven Testing
• Contractor supplies all necessary equipment for performing these tests • For a concrete paving batch plant: • Verification Test only! – performed to verify the total moisture in concrete in • Take initial sample within the first 250 yd3 comparison to water listed on batch ticket • At least one additional sample should be taken if more than 1000 yd3 is produced in a day.
• For a certified ready‐mix plant: • Take initial sample within the first 100 yd3 Microwave Oven Test ‐ Video: • At least one additional sample should be taken if more https://www.youtube.com/watch?v=BykgF0c_CWc& than 400 yd3 is produced in a day. feature=youtu.be
927 928 927 928
Microwave Oven Testing Unit Weight Test
• Testing is performed at the same time Agency aggregate moisture • The Contractor performs a unit weight test on fresh concrete daily testing occurs • This information is used in calculating the total actual water in the concrete sample
• Verify with the batchperson when the aggregate actually gets into the concrete mix (generally 4 –10 loads after the aggregate moisture sample is taken)
• This is when a sample of fresh concrete should be pulled from the agitator or dump truck
929 930 929 930
155 3/4/2021
Microwave Oven Test Procedure Microwave Oven Test
• Weigh up approximately 1500 g sample of fresh concrete • Place sample in glass dish inside fiberglass cloth • Cook at several intervals (5 min, 5 min, 2 min, 2 min, etc.) until sample weight doesn’t change more than 1 gram • Break up sample with grinding pestle between microwaving
931 932 931 932
% Passing the #4 Sieve
• Compare the concrete sample and the mix design
Calculate the incentive based on this number
Mix Design
Concrete Sample Difference > 15 lb/yd3
Difference > 0.02 933 934 933 934
Possible Sources of Error in Water Content
• Batch Ticket vs. Microwave Oven Test • Water Meter Calibration (2461.3.D.1.c) • Testing Errors • Sampling and Testing Procedures • Equipment Ingredient Summary
Rob Golish Specification 2301.3.C.2
935 936 935 936
156 3/4/2021
Cementitious hopper and scales Production Summary
• Observe weighing operation at intervals throughout day • Contractor should provide the Engineer with a production summary in electronic format that includes the following: • Collect invoices from Contractor and assure that the cementitious materials are from certified sources • Daily and final total concrete produced in cu. yd. for each concrete mixture type. • (Spec. 1901.8, 2301.3.E.2, and 2461.3.D) • Daily and final total ingredient quantities (Aggregate, Cementitious and water) including the percent overrun/underrun. • Complete the Concrete Ingredient Summary using the daily production summaries. • Daily and final cement quantity should not show an underrun of greater than 1.0 percent.
937 938 937 938
Ingredient Summary Any Questions???
939 940 939 940
157