Future Trends. Asphalt Rubber. Gregory S. Cleveland, P.E. TxDOT Construction Division. f HMA. f 1

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1 Future Trends Asphalt Rubber N f = f ε 1 ( ) f 2 ( ) f E 3 t HMA Gregory S. Cleveland, P.E. TxDOT Construction Division

2 Outline TxDOT 2003 Standard Specifications Guidance from Flexible Pavement Design Task Force Perpetual Pavements Ride Quality Improvements Summary Question and Answer Session

3 Texas Department of Transportation Standard Specifications For Construction of Highways, Streets and Bridges 2003

4 2003 Hot Mix Specifications Item 340 Dense Graded HMAC Pavement (Method Spec) Item 341 Dense Graded HMAC Pavement (QC/QA Spec) Type A Coarse Base Type B Fine Base Type F Fine Mixture Type C Coarse Surface Type D Fine Surface

5 2003 Hot Mix Specifications Item 342 Permeable Friction Course PG 76 Mixture A-R Mixture

6 2003 Hot Mix Specifications Item 344 Performance Design Mixtures SP-A Base SP-B Intermediate SP-C Surface SP-D Fine Mixture CMHB-C Coarse Surface CMHB-F Fine Surface

7 2003 Hot Mix Specifications Item 346 Stone Matrix Asphalt SMA-C Coarse SMA-D Medium SMA-F Fine SMAR-C Coarse SMAR-F Fine

8 2003 Hot Mix Specifications Item 342 (PFC) and Item 346 (SMA) Specs states to provide a Performance Grade (PG) 76 binder, lime, and fibers unless the plans specify asphaltrubber (A-R) binder. When A-R binder is specified, must meet Type I or Type II requirements of Section I unless otherwise shown on the plans. Use at least 15% by weight of CRM that meets Grade B or Grade C requirements of Section G unless otherwise shown on the plans.

9 Item I I. Asphalt-Rubber Binders. Asphalt-rubber binders are mixtures of asphalt binder and CRM, which have been reacted at elevated temperatures. Property Table 16 Asphalt-Rubber Binders Asphalt-Rubber Binder Type Type I Type II Type III Test Procedure Min Max Min Max Min Max Apparent Viscosity, 347ºF, cp D 2196, Method A Penetration, 77ºF, 100 g, 5 sec. T Penetration, 39.2ºF, 200 g, 60 sec. T Softening Point, ºF T Resilience, 77ºF, % D Flash Point, C.O.C., ºF T Tests on Residue from Thin Film Oven Test: T 179 Retained Penetration Ratio, 39.2ºF, 200 g, 60 sec., % of original T

10 Item G G. Crumb Rubber Modifier. Crumb rubber modifier (CRM) consists of automobile and truck tires processed by ambient temperature grinding. Table 13 Crumb Rubber Modifier Gradations CRM Grade Grade A Grade B Grade C Grade D Grade E Sieve Size / Percent Passing Min Max Min Max Min Max # As As # Shown Approved # On # The # Plans # #

11 Item 300 Table 15 Rubber-Asphalt Crack Sealer Property Test Class A Class B Procedure Min Max Min Max CRM Content, Grade A or B, % by wt. Tex-544-C CRM Content, Grade B, % by wt. Tex-544-C Virgin Rubber Content 1, % by wt Flash Point 2, COC, ºF T Penetration 3, 77ºF, 150g, 5 sec. T Penetration 3, 32ºF, 200g, 60 sec. T Softening Point, ºF T Bond 4, 3 cycles, 20ºF Tex-525-C - pass

12 Item 300 Table 19 Storage, Heating, and Application Temperatures Type - Grade Application Recommended Range, ºF Maximum Allowable, ºF Storage Maximum, ºF AC-0.6, AC-1.5, AC AC-5, AC AC-5 w/2% SBR, AC-10 w/2% SBR, AC-15P, AC-15-5TR RC RC RC MC-30, AE-P MC MC-800, SCM I, SCM II MC-3000, MC-2400L HFRS-2, MS-2, CRS-2, CRS-2H, HFRS-2P, CRS-2P, CMS-2, CMS-2S, AES-300, AES-300S, AES-150P, AES-300P SS-1, SS-1H, CSS-1, CSS-1H, PCE, EAP&T, SS-1P, RS-1P, CRS-1P, CSS-1P, Recycling Agent, Emulsified Recycling Agent, Polymer Mod AE Crack Sealant PG Binders, Modified PG Binders Rubber Asphalt Crack Sealers (Class A, Class B) Asphalt-Rubber Types I, II, and III

13 Item 300 Material Application Hot-Mixed, Hot-Laid Asphalt Mixtures Surface Treatment Surface Treatment (Cool Weather) Precoating Tack Coat Fog Seal Hot-Mixed, Cold-Laid Asphalt Mixtures Patching Mix Recycling Table 18 Typical Material Use Typically Used Materials PG Binders, Modified PG Binders, Asphalt-Rubber Types I and II AC-5, AC-10, AC-5 w/2% SBR, AC-10 w/2% SBR, AC-15P, AC-15-5TR, HFRS-2, MS-2, CRS-2, CRS-2H, HFRS-2P, CRS-2P, Asphalt-Rubber Types II and III RS-1P, CRS-1P, RC-250, RC-800, RC-3000, MC-250, MC-800, MC-3000, MC-2400L AC-5, AC-10, PG 64-22, SS-1, SS-1H, CSS-1, CSS-1H RC-250, SS-1, SS-1H, CSS-1, CSS-1H, EAP&T SS-1, SS-1H, CSS-1, CSS-1H AC-0.6, AC-1.5, AC-3, AES-300, AES-300P, CMS-2, CMS-2S MC-800, SCM I, SCM II, AES-300S AC-0.6, AC-1.5, AC-3, AES-150P, AES-300P, Recycling Agent, Emulsified Recycling Agent Crack Sealing SS-1P, Polymer Mod AE Crack Sealant, Rubber Asphalt Crack Sealers (Class A, Class B) Microsurfacing Prime Curing Membrane Erosion Control CSS-1P MC-30, AE-P, EAP&T, PCE SS-1, SS-1H, CSS-1, CSS-1H, PCE SS-1, SS-1H, CSS-1, CSS-1H, PCE

14 Item 342 (PFC) Table 3 Master Gradation Band and Binder Content % Passing Sieve Size PG 76 Mixtures A-R Mixtures 3/4" /2" /8" # # # Binder Content, %

15 Item 342 (PFC) Table 4 Laboratory Mix Design Properties Mixture Property Test Method Minimum Maximum Drain-Down, % Tex-235-F 0.20 Lab Molded Density, % Tex-207-F, Part VI Fiber Content 2, % Calculated Lime Content 2, % Calculated CRM Content 3, % Calculated 15.0 Stripping Tex-530-C None Cantabro Loss, % Tex-245-F Suggested limit. Test and report for informational purposes only. 2. By weight of total mixture. Not required when using A-R. 3. By weight of asphalt. Not required when using PG 76 and fibers.

16 Item 346 (SMA) Table 6 Master Gradation Bands (% Passing by Wt. or Volume) Mixture Type Sieve Size SMA-C Coarse SMA-D Medium SMA-F Fine SMAR-C Coarse SMAR-F Fine 3/4" /2" /8" # # # # # #

17 Item 346 (SMA) Table 7 Laboratory Mix Design Properties Mixture Property Minimum Maximum Test SMA SMAR SMA SMAR Procedure Mix Mix Mix Mix Design Gyrations, N des Target Lab Density, % Tex-207-F Asphalt Binder Content 1, % Drain-down, % Tex-235-F VMA 2 (Lab Produced), % VMA (Plant Produced), % Fiber Content, % by wt. of total mixture Calculated CRM Content, % by wt. of A-R binder Calculated Hamburg Wheel Track 3, rut 20,000 passes Tex-242-F 122 F, in. Tensile Strength (dry), psi Tex-226-F Boil Test Tex-530-C 1. When SMA mix cannot be designed with a minimum asphalt content of 6.0%, using the available aggregates, follow the guidelines in Table 8 to establish a minimum asphalt content requirement based on the combined aggregate bulk specific gravity. 2. Voids in Mineral Aggregates 3. For SMAR mixes, the number of passes required for the Hamburg Wheel test may be reduced. Other tests may be required for SMAR mixes instead of or in addition to the Hamburg Wheel test, when shown on the plans. 4. May exceed 200 psi when approved. 5. Used to establish baseline for comparison to production results.

18 Item 346 (SMA) Mixture Type Table 10 Compacted Lift Thickness and Required Core Height Compacted Lift Thickness Minimum Untrimmed Minimum Maximum Core Height (in.) (in.) (in.) Eligible for Testing SMA-C SMA-D SMA-F SMAR-C SMAR-F

19 FY Crumb Rubber Usage Summary TxDOT Recycling & Recycled Products Program

20 FY 2000 FY2001 Chip Seal (On Site Blending) 21% Hot Mix 6% Crack Seal 8% Chip Seal (On Site Blending) 41% Hot Mix 22% Crack Seal 6% Chip Seal (AC 15 5 TR) 65% Chip Seal (AC 15 5 TR) 31%

21 Scrap Tire Equivalents FY95-01 (assuming 1 tire = 20 lbs) 1,600,000 1,400,000 Equal to 13,600 tons of crumb rubber 1,366,042 1,200,000 1,111,936 1,000, , , , , , , , , ,000 0 FY95 FY96 FY97 FY98 FY99 FY00 FY01

22 Total Expenditures (in millions) $60.0 $50.0 $49.9 $40.0 $37.8 $30.0 $20.0 $13.6 $15.1 $18.4 $18.8 $10.0 $9.8 $0.0 FY95 FY96 FY97 FY98 FY99 FY00 FY01

23 Flexible Pavement Design Task Force

24 Flexible Pavement Design Task Force Joint effort 1. TxDOT, AGC, and TxAPA 2. Develop ACP specifications that will meet the demands of heavy truck traffic facilities April 23, 2001 memorandum 1. Guidance provided for routes when 30 million ESAL s exceeded 2. Use of SMA and Stone Filled HMAC in lieu conventional QCQA dense graded specifications 3. Exceptions will require approval

25 Categorically Approved Routes 19 of 25 Districts have routes Abilene, Brownwood, Corpus Christi, Lubbock, Odessa, San Angelo do not have routes 33 High-Use Truck Routes listed 1. Waco District first to use specifications 2. Laredo District first to complete a project 3. District s have sent in exceptions for approval

26 Perpetual Pavements

27 HMAC HMAC High Compression Zone Rutting Max Tensile Strain Bottom-up Fatigue Cracking Pavement Foundation Pavement Foundation

28 Mechanistic-Empirical Approach Principles of physics and mechanics of materials are used to determine the pavement s reaction to loading. Critical points in pavement structure are analyzed. Allowable number of load repetitions to limit fatigue cracking: N f = f ε 1 ( ) f 2 ( ) f E 3 t HMA Allowable number of load repetitions to limit permanent deformation: N d = f ε 4 ( ) f5 c

29 Theory of Perpetual Pavements 1. Provide enough stiffness in the upper layer to prevent rutting (limit vertical compressive strain at the top of the subgrade layer). 2. Provide flexibility in the lowest layer to avoid fatigue cracking (limit tensile strain at the bottom of the HMA layer). 3. Durability is a primary concern for all layers and is achieved by the proper selection of materials.

30 Perpetual Pavements }4 to 6 3/4-2 PFC (Permeable, Durable, & Quite) SMA (Impermeable & Durable) Superpave CMHB Ty. A, B, C High Modulus Rut Resistant Material Variable Depth Dense Graded Mix (Impermeable) High Binder Content Flexible Fatigue Resistant Material 3-4 Pavement Foundation

31 Selection of Pavement Layers Based on achieving: Rut Resistant Upper Layers Fatigue Resistant Lower Layers Foundation that provides a stable paving platform, minimizes seasonal variability, and resists volume changes Forces a top down versus bottom up failure mode Utilize Mixture Combinations that Optimize Performance PFC, SMA, Superpave, CMHB, Dense Graded Utilize Full-Depth Hot Mix Approach

32 TxDOT s Vision Statement The vision of the Texas Department of Transportation is to provide transportation systems and alternatives that are comfortable, safe, durable, cost-effective, accessible, environmentally sensitive and aesthetically appealing.

33 TxDOT s Vision Statement The vision of the Texas Department of Transportation is to provide transportation systems and alternatives that are comfortable, safe, durable, cost-effective, accessible, environmentally sensitive and aesthetically appealing.

34 Achieving Objectives Strategy Utilize a multiple tier approach and select the right mixture for the right application This strategy depends on: Traffic volume, loading rate & magnitude, climatic condition, etc. Depth and position of the mixture within the pavement structure. Desired level of service Cost considerations (both initial and life cycle), material availability, etc.

35 8 year old PFC in East Texas without Crumb Rubber, in the rain (in 2000)

36 The Right Mixture for the Right Application!! 8 year old PFC in East Texas with Crumb Rubber, in the rain (no reflective cracking) (in 2000)

37 US Wilbarger Co. Comparison of Vehicle Spray/Ride Quality CRCP SFHMACP PFC

38

39

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41 Concrete Pavement

42 Concrete Pavement

43 Stone Filled HMAC

44 Porous Friction Crse.

45 US 287 (Wichita Falls District) International Roughness Index (IRI) Comparison of 2 Projects Completed in the Fall of IRI (In./mi.) US to US 70/ US to Reference Markers Flexible (PFC + Superpave) Rigid (11" CRCP)

46 Ride Quality (IRI) -Pre Construction Mean Standard Deviation IH20 -R Lane (Dist8) IH20 -L Lane (Dist8) IH 10-R Lane (Dist13) IH 10 -L Lane (Dist13) IH 20-R Lane (Dist6) IH 20-L Lane (Dist6) US 287 L Lane (Dist3) US 90- L Lane (Dist24)

47 Ride Quality (IRI) Project Location Post Construction Mean Standard deviation IH20 -R Lane (Dist8) IH20 -L Lane (Dist8) IH 10-R Lane (Dist13) IH 10 -L Lane (Dist13) IH 20-R Lane (Dist6) IH 20-L Lane (Dist6) US 287 (Dist3) US 90 (Dist24)

48 Project Location IH 10- Yoakum- Gonzales & Fayette counties (Right Lane) IH 10- Yoakum- Gonzales & Fayette counties (Left Lane) IH 20- Odessa- Midland county (Right Lane) IH 20- Odessa- Midland county (Left Lane) IH 20- Abilene- Howard county (Right Lane) IH 20- Abilene- Howard county (Left Lane) US 287-Wichita Falls- Wilbarger county (Right Lane) US 90-El Paso- Presidio county (Left Lane) IRI Pre Construction IRI Post Construction IRI Reduction % % % % % % % % % Average %

49 IH 35 (San Antonio) Ride Quality Measurements IRI (inches/mile) NBL-Before NBL-After SBL-Before SBL-After Avg-Before Avg-After

50 IH 35 (San Antonio) Noise Measurements 100 Decible of Sound Pressur (db) NBL-Before NBL-After SBL-Before SBL-After Avg-Before Avg-After

51 Summary

52 Where is TxDOT Headed?? Release of 2003 Standard Specifications Trans Texas Corridor Research Efforts: Mix design methods and performance criteria for A-R mixtures Guidelines for selecting asphalt mixtures Fatigue research Overlay tester Calibration and possible implementation of the AASHTO 2002 Design Guide for flexible and rigid pavements

53 Overall Goal Improve Comfort, Safety and Durability by using the best available practices for: Paving mixtures Pavement designs Specifications Evaluation procedures (e.g. ride quality)

54 Questions???