Lightweight Fill Applications & Considerations

David Arellano, Ph.D., P.E. Associate Professor The University of Memphis

50th Annual Southeastern Transportation Geotechnical Engineering Conference November 6, 2019 Chattanooga, Tennessee

1 Outline • Lightweight Fill as a Ground Modification Technology • Overview of Various Lightweight Fill Materials • Example Lightweight Fill Embankment Applications • Framework of Design Methodology • Preliminary Selection of Lightweight Fill Materials • What Lightweight Fill Type is the Best?

2 What is considered a lightweight fill?

• A fill material that has a lower unit weight than the unit weight of locally available compacted natural soil fill. – Compacted natural soil fill unit weight typically ranges from about 115‐140 pcf (FHWA GEC 013 2017).

3 Lightweight Fill as a Ground Modification Technology • Ground modification: the alteration of site foundation conditions or project earth structures to provide better performance under design and/or operational loading conditions (USACE 1999; FHWA GEC 013 2017). Nike Warehouses, Memphis

4 Ground Modification Functions (FHWA GEC 013 2017)

• Increase shear strength and bearing resistance • Increase density • Decrease permeability • Control deformations (settlement, heave, distortions) • Increase drainage • Accelerate consolidation • Decrease imposed loads • Provide lateral stability • Increase resistance to liquefaction • Transfer embankment loads to more competent subsurface layers

5 Evaluation of Ground Modification Alternatives

(FHWA GEC 013 2017) 6 Combination Ground Modification Technologies

Nike Warehouses, Memphis

7 (FHWA GEC 013 2017) Overview of Various Lightweight Fill Materials

8 Density and Specific Gravity for Various Lightweight Fill Materials

Basalt 30 to 70 0.5‐1.1 Foamed Glass Aggregate (FGA) 15 to 20 0.2‐0.3

9 (FHWA GEC 013 2017) Categories

Fills with Unconfined Compressive Strength Granular Lightweight Fills

• Geofoam • Wood fiber • Cellular concrete • Blast furnace slag • Boiler slag • Fly ash • Shredded tires Manufactured materials • Foamed glass aggregate (FGA) • Expanded shale, clay & slate (ESCS) • Pumice, basalt

10 Geofoam: expanded‐polystyrene block

11 AL DOT Cellular Concrete

• Concrete made with hydraulic cement, water and preformed foam to produce a hardened material. • Preformed foam is created by diluting a liquid foam concentrate with water in predetermined proportions and passing this mixture through a foam generator.

Photos courtesy of Aerix Industries. 12 Cellular Concrete

Permeable Non‐Permeable

Provided by Mainmark

Photos courtesy of Aerix Industries. 13 Cellular Concrete: Properties

• Wet Density Range: 20 to 80 pcf • Compressive Strength Range: 10 to 300 psi, depending on density • Water Absorption: 1.4 to 15 psf, depending on density • Freeze‐thaw Resistance, 100 Cycles: 92 to 98%, depending on density • Coefficient of Lateral Earth Pressure: Negligible for vertical loads applied directly over the foamed concrete. Lateral Photo courtesy of S.F. Bartlett pressures from adjacent soil mass may be transmitted undiminished.

14 (FHWA GEC 013 2017) Tire Shreds • Dry Density: 21 to 53 pcf loose and 30‐73 pcf compacted • Angle of Shearing Resistance: 19° to 30° • Cohesion Intercept: 100 to 230 psf, use 0 for design • Compressibility: 5 to 40 percent vertical strain over a range of 200 to 4,200 psf vertical stress • Permeability: 0.5 to 60 cm/sec • Type A Gradation (ASTM D6270): 8‐inch maximum dimension; 100% passing 4‐inch, a minimum of 95% passing 3‐inch, a maximum of 50% passing the 1.5‐ inch, and a maximum of 5% https://www.dot.ny.gov/divisions/engineering/technical‐services/technical‐ services‐repository/shreds_rolling.jpg passing the 0.2‐inch sieve • Coefficient of Lateral Earth 15 Pressure: 0.25 to 0.47 (FHWA GEC 013 2017) Wood Fiber

• Moist Density: 45 to 60 pcf • Angle of Shearing Resistance: – Sawdust – 25° to 27° – Hogfuel – 31° – Wood Chips – 30° to 49° • Permeability: 1 x 10‐5m/s • Compressibility: Loose volume reduces 40 percent on compaction. • Vertical subgrade reaction coefficient: 1300 to 1450 psi in

top 2 feet, roughly https://www.google.com/search?rlz=1C1GCEU_enUS819US819&biw= 1280&bih=692&tbm=isch&sa=1&ei=ZMWXXIe1GdC7tgWezb0g&q=wo corresponding to a CBR of 1 od+chip+fill+photos&oq=wood+chip+fill+photos&gs_l=img.3...72436.7 2436..73346...0.0..0.53.53.1...... 1....1..gws‐wiz‐img.‐ 6sfYoh03us#imgrc=pp2nfXxZOy5HlM:

16 (FHWA GEC 013 2017) Expanded shale, clay & slate (ESCS) • Dry Density, Compacted: 50 to 65 pcf • Dry Density, Loose: 40 to 54 pcf • Angle of Shearing Resistance: 35° loose, 37° to 44° compacted • Grain Size Gradation: 3/16 to 1 inch • Permeability: High • Coefficient of Subgrade Reaction: 33 to 37 pci loose, 140 to 155 pci compacted

Publication #6600.4 Revised June 2008 ESCS

17 (FHWA GEC 013 2017) Pumice, Basalt

• Unit weight range (compacted): 30‐70 lb/ft3 • Water absorption: 9% basalt

18 (www.Garibaldi Pumice.com) Photos courtesy : Roch Player Fly Ash

• Density Range, Compacted: 70 to 90 pcf • Shear Strength: 33° to 40°, c = 0, for Type F; Class C is self‐ hardening, so the shear strength will vary as it cures • Permeability: Range of 1 x 10‐ 6 to 1 x 10‐9 m/s

• Compressibility: Cc = 0.05 to 0.37, Ccr = 0.006 to 0.04 • Grain Size Range: 0.005 to 0.074 mm • Specific Gravity: 1.9 to 2.5 Report No. FHWA‐IF‐03‐019 • Atterberg Limits: Non‐plastic

19 (FHWA GEC 013 2017) Air‐Cooled Blast Furnace Slag

• Compacted Moist Density: 70 to 94 pcf, varies with size and gradation • Gradation: Can be graded to any specified size from 4 inches down. • Angle of Shearing Resistance: 35° to 40° • Permeability and Compressibility: Depends http://www.nationalslag.org/blast‐furnace‐slag on final specified gradation. Generally similar to gravel and sand.

20 (FHWA GEC 013 2017) Boiler Slag • Dry Density, Loose: 60 to 78 pcf • Dry Density, Compacted: 82 to 102 pcf • Optimum Moisture: 8 to 20% (Stroup‐Gardiner and Wattenberg‐ Komas 2013b) • Angle of Shearing Resistance: 38° to 42° • Coefficient of Permeability: 0.3 to 0.9 mm/s • Grain Size Range (Percent Passing): 90 to 99% on #4, 62 to 89% on #8, 16 to 46% on #16, 4 to 23% on #30, 2 to 12% on #50, 1 to 7% on #100, and 0 to 5% on #200 (Stroup‐Gardiner and Wattenberg‐Komas 2013b) https://www.acaa‐ • Atterberg Limits: Non‐plastic usa.org/AboutCoalAsh/WhatareCCPs/BoilerSlag.aspx • Compressibility: Comparable to sand, at same relative density 21 (FHWA GEC 013 2017) Foamed Glass Aggregate (FGA)

Table and photo courtesy of T.A. Loux of AeroAggregates. 22 Example Lightweight Fill Embankment Applications

23 Geofoam

Rte 1 & 9, Jersey City, NJ

Photos: Insulfoan/Sutmoller Port of Longview, Longview, WA 24 Cellular Concrete

Colton Crossing, CA Figure and photo courtesy of Steven F. Bartlett Foamed Aggregate Glass

Navy yard Access Project, Philadelphia, PA Photo courtesy of T.A. Loux of AeroAggregates. Basalt

SB405 RSS Renton, WA Figure and photo courtesy Roch Player. Summary of Applications • Road construction over poor • Landscaping & vegetative soils green roofs • Road widening • Retaining and buried wall • Bridge abutment backfill • Bridge underfill • Slope stabilization • Culverts, pipelines & buried • Stadium & theater seating structures • Levees • Compensating foundations • Airport runway/taxiway • Rail embankment • Foundations for lightweight structures

28 Summary of Applications • Special applications: . Noise and vibration damping . Compressible application . Seismic application . Permafrost embankments . Rockfall/impact protection • ????????

29 Framework of Design Methodology

30 Functions of Lightweight Fill Materials

• Lightweight Fill Application: • Thermal insulation Road embankment over soft ground • Compressible inclusion ? • Damping ? Application: • Low earth pressure fill for retaining Integral abutment structures • Structural support ? ? Application: Retaining wall Design by Function

31 Design‐By‐Function Approach

• “Assessing the primary function that the lightweight fill will serve and then calculating the required numerical value of a particular property for that function” (Koerner 1998).

32 Lightweight Fill Embankments Over Soft Soil Ground Conditions • Design and construction of embankments over soft ground is based on avoiding failure during construction by providing adequate stability and limiting postconstruction settlement to desirable amounts (Hunt 1986). What is failure?

33 What is Failure?

• The term “failure” is a loss of function. • Failure or loss of function may occur as either a – serviceability failure (the serviceability limit state, SLS) or a – collapse failure (the ultimate limit state, ULS).

34 Examples of Failure • An embankment over soft soil may experience a serviceability failure due to excessive total or differential settlement that develops over time and which produces premature failure of the pavement system. • An embankment over soft soil may experience a collapse failure through either a rotational (slope stability), lateral spreading, or bearing capacity failure mechanism. The collapse failure may involve at least partial, if not total, collapse. 35 Overall Design Goal

• The overall design goal is to satisfy the following equations for the ULS and SLS respectively: – ULS: resistance of embankment to failure > embankment loads producing failure – SLS: estimated deformation of embankment ≤ maximum acceptable deformation

36 How does use of lightweight fill achieve design goal? • When utilizing normal soil for the embankment, the resistance and stiffness of the soft soil foundation must be increased artificially using soft ground treatment techniques to be able to resist the loads with acceptable deformations and meet ULS and SLS requirements. • With lightweight fill, the approach is to reduce the loads acting on the soft soil and accept the natural resistance (strength and compressibility) of the existing soft foundation soil as it exists to meet ULS and SLS requirements.

37 Application: Roadway Embankment Function: Lightweight Fill

Geofoam or Soil H=1 ft Embankment q=applied stress

Soft soil subgrade

Soil embankment: Lightweight fill embankment: Soil unit weight ≈120 lb/ft3 Unit weight ≈ 1 to 90 lb/ft3 q=(H)(unit weight) q=(H)(unit weight) =(1ft)(120 lb/ft3) =(1ft)(1 to 90 lb/ft3) = 120 lb/ft2 = 1 to 90 lb/ft2

38 Summary of Overall Design Process

1. Identifying the potential failure mechanisms that need to be considered for the required function(s) and application. 2. Identifying the engineering properties that influence the failure mechanisms 3. Identifying the loads that need to be considered in the analysis of each failure mechanism

39 Summary of Overall Design Process (cont.)

4. Evaluating existing design methods typically used in practice to analyze each failure mechanism 5. Developing a design method for analyzing those failure mechanisms for which existing design methods are not available or suitable. 6. Determining tolerable performance criteria for each failure mechanism such as min. FS or max. settlement

40 Identify Failure Mechanisms & Performance Criteria • Allowable total settlement • Allowable differential settlement • Factor of safety for slope stability • Factor of safety for overturning • Factor of safety for sliding • Factor of safety for bearing capacity • Factor of safety for seismic stability • Factor of safety against hydrostatic uplift • Factors of safety against pavement cracking and rutting

Obtained from www.GeoTechTools.org 41 Identify Material Characteristics • Fill type • Fill density • Flammability • Fill water content (water absorption) • Fill creep • Fill susceptibility to petroleum products • Fill allowable load • Fill permeability • Freeze/thaw resistance Settlement? • Flexural strength • Fill friction angle • Fill cohesion • Fill modulus/compressibility • Fill coefficient of lateral earth pressure • Fill gradation • Other unique material characteristics applicable to each type of lightweight fill (see design/analysis procedure summaries in www.GeoTechTools.org ) Obtained from www.GeoTechTools.org 42 Major Components of a Lightweight Fill Embankment

OVERBURDEN MATERIAL (PAVEMENT SYSTEM) FILL MASS

Lightweight Fill Mass

FOUNDATION SOIL

Design must consider the interaction of the various components.

43 Design Phases (5)

Preliminary Embankment Arrangement

External (global) Stability These phases consider the Internal Stability interaction of the major components of the Pavement System Design embankment.

Final Embankment Design

44 Lightweight Fill Embankment Design Framework

45 Preliminary Selection of Lightweight Fill Materials

46 Subsurface Conditions

• Site stratigraphy • Depth to groundwater table • Soil compressibility • Soil initial void ratio • Soil shear strength • Soil variability

Obtained from www.GeoTechTools.org 47 Loading Conditions

• Traffic surcharge • Fill/soil load • Structure load • Water pressures • Earthquake acceleration and duration • Wind load

Obtained from www.GeoTechTools.org 48 Geometry

• Lift thickness • Fill arrangement • Side slope inclination • Overlying pavement thickness • Transition zone

Obtained from www.GeoTechTools.org 49 Preliminary Selection of Lightweight Fill Materials • Settlement will typically be the most critical issue when lightweight fills are considered. • Based on settlement criteria (SLS requirements), can evaluate various lightweight fill types to determine which ones will satisfy settlement. – SLS: estimated deformation of embankment ≤ maximum acceptable deformation • Evaluate settlement of various lightweight types or determine a maximum unit weight that will satisfy settlement requirements.

50 Example: Settlement

Embankment H=5 ft

Clay lb  sat100 ,eCC o 1.7, c 0.3, r 0.04, OCR 1.5 ft3

Tolerable settlement: 4 in. lb Estimated max. unit weight of embankment fill: 30 ft3 Potential lightweight fills: cellular concrete, foamed glass aggregate, geofoam

51 Lightweight Fill Type Selection Factors

• The basic cost of the material. • Transportation costs. • Quantity of material. • Availability of materials. • Placement and/or compaction costs could be higher than for soil fill. Alternative analysis • Availability of the materials. • Construction methods. • Durability of the fill deposits. • Environmental concerns. • Geothermal properties.

(These are cost factors from FHWA GEC 013 2017) 52 Table 3-12. Typical Cost Ranges for Lightweight Fills (FHWA GEC 013 2017)

Costs do not include intangible benefits! Intangible Benefits • Material cost per volume of some lightweight fills is greater than conventional soil.

boobook48.blogspot.com1024

Photo courtesy of Aerix Industries 54 Intangible Benefits . Reduced field installation time and placement in adverse weather conditions resulting in accelerated construction . Shorter time roadway is not in service . Easily adaptable to use of phased construction . Minimum field quality control testing

On many projects, the intangible benefits of using more expensive lightweight fill materials more than compensate for the fact that the material unit costs are greater than that of traditional earth fill material.

55 (NCHRP 24-11(01)) Preliminary Design

• Once the preferred lightweight fill alternative has been selected perform preliminary design. • If the preferred lightweight fill type does not adequately meet the performance criteria of a failure mechanism, perform preliminary design with the 2nd preferred lightweight fill type.

56 The geotechnical “system”. BWC = Build With Confidence (Harr 1987; Holtz 1989).

Application of ly Tolerable Previous al Sampling Testing Analysis Criteria eci sp Experience E BWC Construction

f Project Monitoring in Area o (Arellano) Judgment (Arellano)

1. Engineering judgment without relevant experience is weak. 2. Engineering judgment without relevant data is foolish. 3. Good judgment needs good data and evaluated experience. 4. Good judgment is essential for the effective use of information technology tools. 5. Good judgment is central to geotechnical engineering, even in the information age.

From Allen Marr, Ph.D., P.E., F.ASCE, NAE, "Geotechnical engineering and judgment in the information age," GeoCongress 2006, Geotechnical Engineering in the Information Technology Age. Included in GEOTECHTOOLS website. 57 57 What Lightweight Fill Type is the Best?

58 What Lightweight Fill Type is the Best?

• The one that meets project’s technical and economical objectives. • Combinations of different lightweight fill types and/or ground modification technologies?

59 Geotechnical Research SR‐57 Bridges Over Sr‐23, CSXT & IC RR, Union Pacific Railroad and Scott Street, Memphis, TN: Proposed instrumentation of geofoam embankments between bridges.

Embankment 1: 280 ft long, 8‐26 ft high. Embankment 2: 115 ft long, 42‐44 ft high. 60 Geotechnical Research

Resonant column tests : lightweight cellular concrete.

61 Seismic and Liquefaction Hazard Maps for Northwestern Tennessee

KY MO Lake 2018 Date by county name is expected year of Dyer 2019 TN completion by May of that year. AR Lauderdale 2020 Madison2022 2017‐2022: 5 yrs. Tipton 2021 * Jackson

* Memphis/Shelby Co

Department of Housing and Urban Development National Disaster Resilience Award. 62 Thank You!

David Arellano, Ph.D., P.E. Associate Professor The University of Memphis 104 Engineering Science Building Memphis, TN 38152 901‐678‐3272 [email protected]