Austin District Perspective

Austin District Perspective

District Experience with RAP/RAS = Motivation for Research Construction Issues RAP/RAS Long-Term Performance Issues RAP/RAS Solutions Overview of FM 973 Research WMA/RAP/RAS Project Goals Chronology Story of partnership

With limited funds for pavement preservation: The Department can not afford not to use recycled asphalt and optimize material costs. With that, the Department needs long-term performance from PM measures like overlays because we can t afford to do them twice. We have accomplished the first goal, but not necessarily the second.

Construction: Dry low effective asphalt Appears aged or high oxidized

Construction: Prone to Ravel and Segregate Low Eff. AC

Construction: High air voids Stiff mix prone to segregation and difficult to compact

Construction: Tearing Stiff mixture Crushed Aggregate Extra Compactive Effort

Construction: Premature Cracking or Failure During Construction Longitudinal Cracking Fatigue Cracking

Long-term Performance Premature Cracking Raveling Accelerated Deterioration Increase in Maintenance Costs (in some cases) Reduced Performance Life (in some cases)

One of the first overlays with RAP in surface mix July 2009 PG 70-22 TY C PG 64-22 with 20% RAP Hamburg = 4 mm.@ 15,000passes Sign of raveling and cracking within 8 months of overlay Cost Saving = $19,500 (grade dumping) Total In-house Maintenance Cost (2009-2012)= ~$75,000 Crack Seal and Level-Up 30% Drop in Condition Score in 3 years Performance Life = 3 years

One of the first overlays with RAP/RAS May 2010 PG 70-22 TY C SAC B 15% RAP/5% RAS with PG 64-22 Hamburg = 2.1 mm.@ 20,000passes Alligator & Longitudinal Cracking Cost Saving = $17,555 (grade dumping) Total In-house Maintenance Cost (2012)= ~$2450 (Crack Seal) Level-Up & Seal Coat RMC FY 14 or 15 ($530,000) 18% Avg. Drop in Condition Score in 2 years Performance Life ~ 3-4 years

Analyze PMIS database for trends of cracking versus rutting over past fiscal years Crack/Rut Ratio = Total Percent Cracking per Lane Mile Total Percent Rutting per Lane Mile

18.0 16.0 14.0 12.0 Ratio: Percent Cracking per Percent Rutting 1 st SP 341-020 (FRAP) projects let March 2009 1 st SP 341-024 (RAS) projects let December 2009 11.5 14.2 16.4 RUT/CRACK RATIO 10.0 8.0 6.0 5.5 7.0 4.0 2.0 0.0 Austin FY2008 Austin FY2009 Austin FY2010 Austin FY2011 Austin FY2012

Increase Target Density to 97% for all mix with recycled asphalt Minimum Rut Depth of 3 mm. Implemented the Austin District Thin Overlay Program for surface courses PM Research FM 973 Project Research

Study in WMA/RAP/RAS

District Goals for FM 973 test section: Confirm what we, as a District, have observed Calibrate the amount of recycled asphalt allowable without compromising long-term performance Collaborate on other possible solutions in utilizing WMA/RAP/RAS as a cost savings measure Help make a GOOD idea a GREAT idea

April 13, 2011 RAS Workshop TTI, TxAPA, CST & Austin District Discussion about a potential test section in the Austin District Austin District & TxAPA identified potential projects and willing Contractors

FM 973: Accelerated Pavement Test Section From FM 969 to SH 71 2 Mill, Seal & Inlay TY C PG 70-22 SAC B 8 HMA/ 11 FLBS Soft silty/sandy clays marginal subgrade ADT = 10,700 % Truck = 9.1% (ADT-975) Heavy Trucks Ready Mix Plant, Sand & Gravel Pit, ABIA Freight, and other Industrial traffic

Study Title PI(s) Organization TxDOT 0-6614 Use of Recycled Asphalt Shingles in HMA Fujie Zhou TTI TxDOT 0-6092 Performance Evaluation & Mix Design for High RAP Mixtures Fujie Zhou TTI TxDOT 0-6613 Evaluate Binder & Mixture Aging for Warm Mix Asphalts Charles Glover TTI NCHRP 9-49 Performance of WMA Technologies: Stage I--Moisture Susceptibility Amy Epps Martin, Cindy Estakhri TTI NCHRP 9-49A Performance of WMA Technologies: Stage II--Long-Term Field Performance Shihui Shen Washington State University

First Official Meeting July 7,2011 Determined the matrix of different combinations of WMA/RAP/RAS/PG 9 Test Section Administrative Item Change order Costs ~ $55,000 Schedule Field Testing AUS: FWD/GPR/IRI TTI: Condition Survey Mixture FM 973 Field Test Sections Asphalt Binder Grade RAS, % RAP, % 0 15 35 HMA 64-22 0 1 2 3 3 5 4 58-28 0 5 3 6 WMA-1 64-22 0 7 5 3 5 58-28 0 WMA-2 64-22 0 8 3 5 3 9 5 58-28 0 3 5

FM 973 Between FM 969 and HWY 71 Section No. Type Binder RAP RAS 1 HMA 70-22 0 0 7 8 9 WMA Foaming WMA Evotherm WMA Evotherm 70-22 0 0 70-22 0 0 64-22 15 3 3 HMA 64-22 15 3 4 HMA 64-22 0 5 2 HMA 64-22 30 0 5 HMA 58-28 30 0 6 HMA 58-28 15 3 Austin Bergstrom Int. Airport Sections highlighted in yellow being used in this project Type C mix Limestone C, D, F, Mfg. Sand + Field Sand Section length ~ 2,040 ft Sections 1 & 7: 400 tons Sections 2-6, 8, 9: 800 tons

September 9, 2011 Mix Design & Trial Batch Testing Plan RTI/TxDOT (AUS)/ TxDOT (CSTMP) Developed plans for sampling at plant and field TTI/RTI/TxDOT(AUS) Developed experimental testing plan TTI/TxDOT(CSTMP)

NCHRP 9-49 TxDOT 6613 TEXAS FM 973 Test Sections Raw Materials TxDOT 6614 NCHRP 9-49A Evotherm Loose Plant Mix (5-gal buckets) On-site specimens b No. Type Bin der R A P R A S Agg/ RAP/ RAS (55-gal drum) Binder (5-gal bucket) WMA (gal or lb) a Binder (5-gal bucket) Binder (5-gal bucket) Aggreg ate (5-gal bucket ) Binder (5-gal bucke t) WMA Additi ve (gal or lb) a Binder (5-gal bucket) RAP (5-gal bucke t) RAS (5-gal bucke t) NCHRP 9-49 TxDOT 6613 TxDOT 6614 NCHRP 9-49A Evotherm NCHRP 9-49 1 HMA 2 HMA 70-22 0 0 3 2 1 6 1 2 5 8 5 5 5 64-3 22 0 0 2 5 5 6 (6 x 3.75 ) 7 (6 x 2.4 ) 3 HMA 4 HMA 5 HMA 6 HMA 64-22 1 5 3 3 2 2 2 1 5 5 5 64-22 0 5 5 5 58-3 28 0 0 2 2 5 5 58-1 28 5 3 5 5 6 (6 x 3.75 ) 7 (6 x 2.4 ) 7 WMA Foaming 70-22 0 0 3 2 1 6 1 5 8 5 5 6 (6 x 3.75 ) 7 (6 x 2.4 ) 8 WMA Additive 70-22 0 0 3 2 1 or 9 1 6 1 1 or 9 5 8 5 5 6 (6 x 3.75 ) 7 (6 x 2.4 ) 9 WMA Additive 64-22 3 1 5 3 2 1 or 9 5 5 6 (6 x 3.75 ) 7 (6 x 2.4 )

TEXAS FM 973 Test Sections Field Cores No. Type Binder RAP RAS NCHRP TxDOT TxDOT WSU 9-49 6613 6614 Total 1 HMA 70-22 0 0 6 12 6 5 29 2 HMA 64-22 30 0 10 10 3 HMA 64-22 15 3 12 5 17 4 HMA 64-22 0 5 10 10 5 HMA 58-28 30 0 10 10 6 HMA 58-28 15 3 10 10 7 8 9 WMA Foaming WMA Evotherm WMA Evotherm 70-22 0 0 6 12 6 24 70-22 0 0 6 12 6 24 64-22 15 3 12 12 24 TOTAL 158

PAVE _IR

Met March 28, 2012 Wrap up & Lessons Learned Field Testing TxDOT (AUS) FWD, GPR, & IRI Condition Survey No Distress, but difference in color and appearance Coring - TxDOT (AUS) & TTI 178 January 2012 142 September 2012

Rut Depth (mm) 5 4 3 2 1 0 Hamburg Test@10000passes OT Cycles 80 70 60 50 40 30 20 10 0 Section Type Binder RAP RAS 1 HMA 70-22 0 0 2 HMA 64-22 30 0 3 HMA 64-22 15 3 4 HMA 64-22 0 5 Overlay Test

Rut Depth (mm) 10 9 8 7 6 5 4 3 2 1 0 Hamburg Test@10000passes PG64-22/30%RAP PG58-28/30%RAP OT Cycles Section Type Binder RAP RAS 2 HMA 64-22 30 0 5 HMA 58-28 30 0 25 20 15 10 Overlay Test 5 0 PG64-22/30%RAP PG58-28/30%RAP

1000 900 Resilient Modulus ( Room Temperature 25C) 800 700 600 500 400 300 200 100 HMA Evotherm Foaming HMA +RAP/RAS Evotherm+RAP/RAS" 0 1 2 3 4 5 6 7 8 9 Time (Weeks)

Initial findings and conclusions from research RAP/RAS improves early age distresses (rutting, moisture susceptibility) at the expense of fatigue resistance WMA & HMA are different initially, with HMA exhibiting greater fatigue resistance With aging, WMA appears to catch up to HMA (WMA = initial HMA), in term of stiffness Research testing and analysis on-going, but correlates with observed performance

With limited funds: The Department can not afford not to use recycled asphalt and optimize material costs. The Department can not afford to maintain and replace poorly performing overlays that last only a few years. Joint ventures, like the FM 973 test section, is the type of partnering between the Department, Industry, and Academia that result in innovations and solutions to bridge these two goals.

Specify a minimum virgin AC% Discount the contribution of recycled asphalt to the total asphalt content or lower recycle asphalt ratios Minimum penetration requirement for RAP and RAS Processing RAP or RAS with conditioners or rejuvenators prior to incorporation in HMA Limit use of mixture with recycled asphalt on high deflection roadways FM roads

Planning future test section on FM 973 to study new techniques & admixture to improve performance of mixtures with RAP/RAS WMA or rejuvenators to pretreat RAP & RAP stockpiles Nano technology to promote better effective asphalt

Ramming Chuck Fuller, David Fuller, Jimmy Whithed TTI Arif Chowdhury, Amy Epps, Jon Epps, Cindy Estakhri, Tom Scullion TxAPA David Kopp, Harold Mullins, Kyle Swaner TxDOT (CSTMP) Robert Lee, Dale Rand TxDOT (AUS) Austin District Lab, Travis East Maintenance Office, Tommy Blackmore