Recycling Emulsions for Pavement Preservation “Going from Good to Great to Green”
Presented by: Wade Miller Western Emulsions, Inc. Western Emulsions, Inc. • Founded in Dec. 1977 • 5 Plants and Terminals in 4 States • 10 DOT’s in Western States Footprint • Most recent March 2009: Grand Opening of Emulsion Plant in Roswell, New Mexico
Our Business • Emulsions Manufacturing • Liquid Asphalt Sales • Transport Asphalt Emulsions • Spread Asphalt Emulsions • Technical Consultation Pavement Preservation Defined • Integrated, cost-effective set of practices that extend pavement life, improve safety and meet motorist expectations.” • Proactive program employing a network- level strategy to enhance performance
• “The right treatment for the right road, at the right time” Pavement Preservation Benefits • Cost Savings – Surface treatments save 80 – 98% of the cost per lane-mile compared to mill & overlay • Jobs – PP creates 25% more, dollar-for-dollar, compared to reconstruction • Environmentally superior to traditional R&R – GHG Emissions – Energy consumption – Solid waste/landfill impact What are Emulsions? • 60%-70% Asphalt • 30%-40% Water • Two major components will not mix (they are insoluble) • Definition of an Emulsion: A mixture of two insoluble liquids Why Emulsions v. Hot AC? • Lower working temperatures • No heat needed - energy savings • Easy to use at remote locations • Breaking process controlled by chemistry • Can be easily recycled in the future Growing Usage of Emulsions • The United Stated systems of roads and highway-valued at over $1.75 trillion is steadily deteriorating. The American Society of Civil Engineers (ASCE) 2009 Report Card for America’s Infrastructure give a grade of D- for the nation’s roads. ASCE estimates the total cost of repairs and needed upgrades is $2.2 trillion. • Pavement Preservation (Asset Management) • Recycling • Declining Budgets • Environmental Concerns Emulsions Not All Created Equally • Slow-setting (old technology) v. Rapid-setting (new technology) • Cutback-based (old-technology) v. Solvent- free (new technology) Cutback Emulsions
Emulsions Used by DOT - 85% are slow-setting type emulsions - 75% contain solvents (kerosene, diesel, naptha) The Western Emulsions Difference • Technological Innovations – Solvent-Free Materials – Rapid-setting Products – More eco-efficient, cost-effective processes • Now used as alternatives to the cutback products Why rapid setting emulsions?
• Weather friendly • Less motorist inconvenience • Less likely to cause environmental issues • Labor Savings Western Emulsions’ Innovations • Our Emulsions were green before green was popular • Energy efficient • Water based • Low temperature handling • Little or no emissions with most emulsions • Recycling, sustainability Pavement Preservation Using PASS® - Treatment Strategies
New Solutions • Emulsions vs. Hot Mix Asphalt • Preservation rather than reconstruction • Reduced Emissions Pavement- Warm Mix • Cold-In-Place Recycling-CIR • Full Depth Recycling-FDR • Solvent Free Prime-AEP • Scrub Seals-Cape Seals • 100% Reclaimed Aggregates Three Processing Methods • There are three PASS R /RAP processing methods which are being successfully used today by both agencies and contractors: – 1. Grade processing, compaction and sealing – 2. Grade mixing, laydown and compaction – 3. Central plant mixing, stockpiling, laydown and compaction Applications Grave Emulsion Full Depth Reclamation Max 13”
Base Stabilization
Max Depth 13”
Cold In-Situ Recycling 2” Cold Mix Wearing Coarse Where Can PASS-R Be Used
“Pavement Preservation” Cold Mix 101 “Cold Mix Paving” • Slurry seal • Road Building • Microsurfacing Structural Layers • Chip seal PAVEMENT LAYERS • Tack coat
WEARING COURSE TOP SOIL BASEBASE TOP SOIL
SUB-BASE
SOIL STABILIZED ROADBED Stockpilable 1 week – 1 month Windrows Start Grader Good Workability Compacted Immediately Compaction
ETB - Emulsion Treated Bases & GEM - Granular Emulsion Mixes
Recycle (RAP) Emulsion Mix – Central Plant Mixing Recycle (RAP) Emulsion Mix – Central Plant Mixing Recycle (RAP) Emulsion Mix – Central Plant Mixing Blade Laid Recycle (RAP) Emulsion Mix – Central Plant Mixing Paver Lay-down and Compaction Recycle (RAP) Emulsion Mix – Central Plant Mixing Windrow Lay-down, Paver Laid Recycle Applications – Cold In Place Recycling
Cold-In-Place-Recycling Train Recycle Applications Cold In Place Recycling
CIR Paving/Lay-down Equipment COLD MIX FOR RE-DIMENSIONING AND REINFORCING OLD PAVEMENT
Widening Cold Mix
Stabilized Shoulder Old Pavement Old Pavement Base Profile of old road and new road geometries Preservation Strategies Rejuvenating Fog Seals Rejuvenating Scrub Seal / (Quick Breaking) Cape Seal RAP Slurry Seal, Micro- Surfacing and Chip Seal CIR Train-Yellowstone National Park
• Recouping investments in aging infrastructure America needs its roads, but they are aging. Vehicle miles traveled in the U.S. have increased five-fold over the past 50 years to 3 trillion vehicle miles in 2006. Roadways are becoming distressed, carrying heavier loads than originally intended. New Technologies: • Solvent-Free Cold In- Place Recycling (CIR)
• Solvent-Free Full Depth Reclamation and Granular Base Stabilization (FDR/GBR) • Vapor Barriers • Soil Remediation Trackless Fog Seals New Technologies
Trackless Tack and Bond Coats Full Depth Reclamation Solvent Free Cold Mix, with Virgin Aggregate or RAP
Warm Mix Asphalt
Global Warming and GHG Emissions
EPA proposes mandatory reporting of GHG by large emitters on 3-10-09 GHG emissions per tonne of laid material
200 180 160 17% of HMA Laying 140 Transport 120 Manufacture 100 Aggregates 80
60 Binders GHG emissions (kg/t) emissions GHG 40 20 0
Cold mix asphalt Thermorecycling
Bituminous concrete
Cement-bound aggregate Emulsion in-situ recycling Road base asphaltWarm concrete mixEmulsion asphalt bound concrete aggregate Untreated granular material
High modulus asphalt concrete Continuous reinforced concrete Cement-bound agreggate & "AJ" Concrete bituminous with 10% RAP Soil treated in-situ with lime + cement Aggregate withCement hydraulic concrete road slabsbinders without dowels
Road baseRoad asphalt baseRoad asphalt baseconcrete asphalt concrete with concrete 20% with RAP 30% with RAP 50% RAP Aggregate with hydraulic road binders & "AJ" Why Environmentally-Friendly Emulsions? • IARC • Higher Temperature • Kyoto Treaty Trends • Naphthalene & PAH • Rising Energy Costs Emissions • Odors • Particulate Emissions • Increased Activism • Regulatory & Permitting • No Premature Oxidation
Ergon & Western Emulsions CIR
Sealing Compacted Grade Sealing Compacted Roadway Gradation of RAP and Compactive Effort – Unbound Pavement Douglas County, NV – Carson Valley Only a very few micro cracks have appeared in over 80 miles of PASS/RAP pavements after 5 winters. Routine preventive maintenance consists of a fog coat of PASS (1:1) at 0.6-0.12 gsy at 3-5 year intervals Luna County New Mexico PASS/RAP with chip seal cap Luna County, New Mexico Table Mixed PASS/RAP RAP Mix
• RAP millings from ¾” original mix, screened on 1 1/2” sieve • 2-3% pre-mix water added to mixing table Table Mix
• 7% PASS R (1:1), or 3.5% PASS R emulsion concentrate, was added to pre-wet millings in mix table PMRE /RAP Stockpile • Table mix was stockpiled with bucket loader 1- 4 days after mixing Blade Laydown of Stockpiled Mix Wexford Rd Wilhoit
• PMRE/RAP mix was hauled by truck (approx. 25 miles) to Wilhoit where it was paver laid on a compacted RAP base (5-6”) • Burmed RAP millings for shoulders had been fogged with PASS 1:1 Wexford Rd. • No problems with paver laying • No sticking in paver or haul trucks Wexford Rd
• 2 Steel wheel rollers • 2 passes in vibratory mode, 2 passes static established as optimum rolling pattern. Rubber tire roller can iron out imperfections for several days following laydown. Wexford Rd
• 1 Day after placement and compaction • Wexford Rd open to traffic during construction • New mat open to traffic 2-3 hours after rolling Wexford Rd
• 30 days after placement, no surface treatment • Yavapai County fog sealed road with PASS QB after 6 weeks; chip seal was applied after 4 months
Ponderosa Park Ponderosa Park Paver Lay Ponderosa Park
Uncompacted, compacted mat Superstition Rd Superstition Rd
Chip sealed 3 mos. After paving Yavapai County
• Almost 10,000 tons of screened millings were pugmill mixed with PMRE called PASS R at 3.5% emulsion with moisture content at similar % . The processed material was stockpiled for paver laydown over several weeks. RAP Processing Yavapai County RAP Feed Conveyors from Hoppers PMRE/RAP pugmill to stockpile
Twin shaft pugmill Processed Millings 7% PASS PMRE/RAP Laydown YC PMRE/RAP Uncompacted Mat PMRE/RAP Rolling and Compaction Millings for Pavements • The low temperature flexibility of PMRE rejuvenating binders, combined with the polymer network, enable PMRE emulsions to bind RAP millings (grindings) together within a mix and to all compacted surfaces. • Solvent free PMRE eliminates the ‘slickness’ of rejuvenating oils such as ERA’s PMRE/RAP Summary
• Mixing: • Laydown – Mix table – Blade – Windrow – Paver – Pugmill – CIR (screed) – CIR
– Stockpile up to six weeks Compaction and Maintenance
• Steel wheel • Fog sealing – Immediate breakdown – Recommended during and 2nd pass in vibratory first 60 days mode • Chip sealing – May iron out slight – recommended during imperfections during first 6 months if week following pavement has very placement with coarse surface texture or pneumatic roller if raveling occurs Cost Comparisons
• Bound RAP can be produced for $12 to $20 per ton depending on processing equipment • Estimate cost of 1/3 to 2/3 that of hot mix per ton • Processing should be determined by design need based on traffic volumes and loads Summary • Unbound millings can be used to produce a desired grade and surface-sealed with PMRE Emulsions for long lasting low volume roads with the texture of hot mix and no loose aggregate • PMRE bound millings can be used to provide pavements with material properties rivaling hot mix for a fraction of the cost What’s next? Reclaimed Aggregates
• 100% Recycled Aggregate Slurry • 100% Recycled Aggregate Chip Seals Contact Information
• Wade Miller • Vice President of Marketing • Western Emulsions, Inc. • Ph: 949 248-8020 • Fax: 949 248-8023 • Mob: 949 337-5133 • E-mail: [email protected] • www.westernemulsions.com COLD IN-PLACE RECYCLING (CIR)
Starting with what is there i.e. in situ materials Definitions:
ARRA (Asphalt Recycling/Reclaiming Ass.) Cold In-Place Recycling (CIR) is the on-site recycling process to a typical treatment depth of 2 to 5 inches, using a train of equipment (tankers, trucks, milling machines, crushing and screening units, mixers, pavers and rollers), an additive or combination of additives (asphalt emulsion, rejuvenating agents, lime, fly ash, cement), generating and re-using 100% RAP, with the resulting recycled pavement usually opened to traffic at the end of the work day. Definitions: continued
Granite Construction Company: Cold in-place recycling is performed by milling, screening, and crushing existing asphalt pavement at the work site. We restore the crushed asphalt by blending it together with a rejuvenator (usually an emulsion) and laying the material to form new pavement. Since the process occurs as one continuous operation, cold in-place recycling is an efficient and cost-effective method of revitalizing roads while recycling 100% of the existing road material. Definition: simplified
• CIR is an environmentally responsible, cost effective and value added process making an interlayer from in situ asphalt paving, using appropriate emulsions, such as PASS R, and strengthening additives. Process Particulars and/or Nuances:
• Substitute for HMA?.....NO! NO! NO! Process Particulars:
• Milling • Crushing • Additives • Mixing • Lay-down • Coating • Compaction Milling:
• Types of milling machines—down-cut & up-cut
• Size of RAP
• Miller usually pulls the train
• Liquid additives can be sprayed into milling chamber; cutter mandrel needs cooling water Milling Milling Milling Crushing
• Re-circulating crushers are common with up- cutting trains
• Maximum RAP size
• Crushing too fine may cause poor coating
• Modify gradation by adding virgin material Crushing Crushing Crushing Crushing Crushing Additives
• Liquid additives can be incorporated thru the milling chamber or into the pug-mill – Emulsion/rejuvenators e.g. PASS R – Lime or cement slurries – Water • Rule of Thumb—5% Total Fluids • Dry additives are spread in front of train – Sand, Gravel, Cement, Lime, Fly-ash, etc. Additives Additives Additives Mixing
• Multiple-unit trains: use twin shaft pug-mill
• Single-unit trains: mandrel cutter chamber
• Sufficient water required for coating
• Mixed CIR dropped out of rear of pug-mill Mixing Mixing Mixing Mixing Lay-Down
• Normal windrow paving equipment used
• Material can also be blade laid
• CIR is wet—Don’t Ever Heat the Screed!!
• CIR is not HMA—Has its own behavior Lay-Down Lay-Down Lay-Down Coating
• Incomplete coating of larger RAP particles
• Emulsion sticks to AC matrix around RAP
• Exposed/Fractured Faces not well coated
• Can Flush/Fog Coat Surface Coating Coating Compaction
• Many schools of thought and theories • Same equipment employed as with HMA • Mediums/Vehicles of Compaction – HMA uses heat – CIR uses water • Laboratory and Field Methods – 95% of Marshall?? – 88% of MTD? – Rolling Patterns, Test Strips, Max Obtainable Compaction Compaction Field Operations Control Processes • Climatic Conditions
• Pavement Conditions
• Traffic Control
• Grade Control
• Opening Roadway to Traffic
• Payment Climatic Conditions
• Ideal—Hot, Dry and Breezy
• Avoid Rainy Weather or Threat of it
• CIR can be done in cool weather, but it will take longer for the material to cure out.
• Curing of material is effected by humidity Pavement Conditions
• Free of debris—not necessarily swept
• Repair soft, spongy, subgrade failures
• For extensive repair consider FDR
• Assure adequate & uniform width Traffic Control
• CIR an in-line process—need only 1 lane
• Going against traffic mitigates stopping and starting problems under early traffic
• Allow sufficient time each day to roll-out Traffic Control Grade Control
• Miller & Paver have depth/grade controls
• Paver also has screed and slope controls
• Improvements to ride will occur
• Can make minor cross-slope adjustments
• Material must balance—negates grade changes Opening to Traffic
• Usually traffic can occupy CIR same day
• Suggest opening a section at mid-day to ascertain whether it will sustain traffic – May need or want to LIGHTLY Fog-Coat – Allow Fog-Coat to penetrate before opening – Too much Fog-coat will require light sanding – Perhaps County can do fogging and sanding Payment
• Most CIR is paid by the Square Yard
• Use different items for different depths
• Emulsions and additives paid by the ton
• Water is incidental to the work
• Accurate quantities & specs. yields better prices Characterization of CIR
• Design Parameters: – Modulus – Voids – Strength
• Characterization of Product Properties Modulus
• 2008 AASHTO MEPDG uses moduli and states overlying modulus is not to exceed 3 times the underlying modulus
• CIR is bound but not as bound as HMA
• Resilient Modulus of CIR is mid-range: 200k psi.
• Relationship with Elastic Moduli & Stability Voids
• As a design parameter could control CIR stiffness as well as porosity
• Voids of CIR are commonly around 12% – Sufficient to maintain its modulus – Offers good resistance to crack propagation – Low enough to resist rutting Strength
• Paving layers generally have a surrogate strength requirement: many are flexural
• Marshall and Hveem have strength-like test procedures but are run at HMA temp.
• CIR specimens have tender surfaces and don’t lend themselves well to some tests Characterization of CIR Properties
• CIR is produced from the existing asphalt concrete paving layers using in-place recycling methods, creating an interlayer of semi-bound material of medium modulus, higher voids resisting crack propagation and enhanced resiliency to the pavement structure, while being of sufficient strength to withstand loads transmitted from the overlying layer(s) of asphalt concrete. CIR can be designed, constructed and placed to meet almost whatever parameters are required and conditions that are encountered in the field, including the occasional and/or temporary possibility of it being the top ridding surface or in some cases even the final roadway surface.