Experience with RAP and RAS at the MnROAD Research Facility. Tim Clyne NCAUPG Technical Conference January 23, 2013

Transcription

1 Experience with RAP and RAS at the MnROAD Research Facility Tim Clyne NCAUPG Technical Conference January 23, 2013

2 A full-scale accelerated pavement testing facility that gives researchers a unique, real-life laboratory to study and evaluate the performance of materials used in roadway construction MnROAD Office of Materials & Road Research

3 MnROAD Background History Original Funding ($25 million) Original Construction ( ) Open to Traffic (1994) Major Experiments Phase I ( ) Phase II (2007-present) Phase III (2016 ) Layout and Designs Mainline / Low Volume Asphalt / Concrete / Aggregate 3,5,10 Year Designs

4 Traffic Loadings Low Volume Road Traffic MnROAD 5-axle Semi Inside Lane = 80k truck 5 days/week Outside Lane = 102k truck (pre-2007); no traffic since then Mainline Traffic I-94 WB Public Traffic 28,500 AADT 12.7% Trucks

5 Pavement Performance Monitoring Non destructive testing Dynamic load testing Distress surveys PCC joint faulting Noise Texture Friction HMA rutting Coring Forensics

6 Instrumentation Soil Pressure HMA and PCC Strains Deflection Weigh in Motion Temperature Moisture Frost Water Quality

7 Oracle Database Over 1 Billion rows MnROAD Database Data Release 1.0 (January 2012) Test cell parameters Monitoring/Performance Lab testing results Current Activities Sensor data Table organization & data validation procedures Web access Data Release 2.0 (Jan 2013)

8 MnROAD Phase I Benefits Improved policies and specifications save Minnesota $33M annually Seasonal Load Limits Improved Design Methods Improved Construction Techniques Training & Education 18 Years of Data to Share

9 Local, National, & International Partners

10 Transportation Engineering & Road Research Alliance (TERRA) Broad partnership of government, industry and academia Develop, sustain and communicate a comprehensive program of research on pavement, materials and related transportation engineering challenges, including issues related to cold climates

11 Motivation for Using RAP & RAS Reduce carbon footprint of product Conservation of natural resources Conservation of landfill space Stabilize material costs, i.e. raw material costs continually fluctuate RAS contain sand, (very stiff) asphalt, fiber

12 RAP & Shingles at MnROAD 0, 20, 30% RAP (fractionated) 5% Shingles (MW & TO) PG & HMA & WMA Questions: Material processing & handling Degree of blending Mixture durability (cracking potential, moisture damage)

13 Shingle Properties MWSS 98% Passing # 4 Sieve 1.2% Deleterious Materials (Out of Spec. <0.5%) 17.8% Asphalt Content TOSS 100% Passing # 4 Sieve < 0.5% Deleterious Materials 26.4% Asphalt Content

14 RAP & RAS Extracted Binders Material Identification High PG Temp, C Intermediate PG Temp, C Low PG Temp, C Performance Grade MWSS TOSS RAP % MWSS % TOSS % RAP

15 Dynamic Modulus

16 Flow Number

17 SCB Fracture Energy RAP

18 SCB Fracture Energy RAS

19 Beam Fatigue Mix ID % Binder Replacement Endurance Limit (µε) 5% MWSS % TOSS % RAP

20 Lab Testing and Evaluation Pronounced differences between MWSS and TOSS (TOSS is stiffer) Soft binder leads to soft mixture Less rutting observed in RAS mixes (stiffer can be good) Fracture resistance decreases with increasing recycled content

21 FWD, Years 1 and 2

22 Ride Quality

23 Visual Distress Survey RAP Mixtures Reflected Cracks: 32% of prior cracks reflected on Cell 15 (3- in. overlay of full depth asphalt) Cell 16 has two cracks PG w/ 30% RAP is starting to crack

24 Field Cracking Performance RAS

25 Field Performance Summary Structural capacity of all cells is similar Ride quality heavily influenced by seasonal variations and construction Difficult to distinguish between RAP/RAS % Early cracking is a result of reflective cracking, not thermal cracking None of the test sections show excessive rutting (not presented here)

26 MnDOT Specification 2360 neat modified Requirements for Ratio of Added New Asphalt Binder to Total Asphalt Binder min% Recycled Material Specified Asphalt Grade PG XX-28, PG 52-34, PG 49-34, PG Wear Non-Wear RAS Only RAS + RAP RAP Only PG 58-34, PG 64-34, PG Wear & Non-Wear Maximum 5% shingles (TOSS or MWSS) Blending charts may be used to verify compliance

27 Acknowledgements Chris Williams, Iowa State University Mihai Marasteanu, University of Minnesota Ed Johnson & Jerry Geib, MnDOT Pooled Fund Study TPF-5(213) Federal Highway Administration MN Local Road Research Board

28 Tim Clyne