Tim Clyne NCAUPG Technical Conference January 23, 2013

Experience with RAP and RAS at the MnROAD Research Facility

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

MnROAD Background History

Original Funding ($25 million) Original Construction (1992-

1993) Open to Traffic (1994)

Major Experiments

Phase I (1994-2006) Phase II (2007-present) Phase III (2016…)

Layout and Designs

Mainline / Low Volume Asphalt / Concrete / Aggregate 3,5,10 Year Designs

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

Traffic Loadings

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

Instrumentation

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

MnROAD Database Oracle Database

Over 1 Billion rows 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)

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

Local, National, & International Partners

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

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

0, 20, 30% RAP (fractionated) 5% Shingles (MW & TO) PG 58-28 & 58-34 HMA & WMA

Questions: Material processing & handling Degree of blending Mixture durability (cracking

potential, moisture damage)

RAP & Shingles at MnROAD

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

RAP & RAS Extracted Binders

Material Identification

High PG Temp, °C

Intermediate PG Temp, °C

Low PG Temp, °C

Performance Grade

MWSS 109.1 - - -

TOSS 122.5 - - -

RAP 73.5 31.7 -10.8 70-10

5% MWSS 71.3 18.5 -21.7 70-16

5% TOSS 71.1 19.7 -21.2 70-16

30% RAP 68.8 20.6 -22.7 64-22

Dynamic Modulus

Flow Number

SCB Fracture Energy – RAP

SCB Fracture Energy – RAS

Beam Fatigue

Mix ID % Binder Replacement

Endurance Limit (µε)

5% MWSS 18.8 131

5% TOSS 26.0 123

30% RAP 33.3 89

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

FWD, Years 1 and 2

Ride Quality

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 58-28 w/ 30% RAP is starting to

crack

Field Cracking Performance – RAS

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)

MnDOT Specification 2360

Maximum 5% shingles (TOSS or MWSS) Blending charts may be used to verify compliance

www.mndot.gov/materials/bituminous.html

Requirements for Ratio of Added New Asphalt Binder to Total Asphalt Binder min%

Specified Asphalt Grade

Recycled Material RAS Only

RAS + RAP

RAP Only

PG XX-28, PG 52-34, PG 49-34, PG 64-22 Wear Non-Wear

70 70

70 70

70 65

PG 58-34, PG 64-34, PG 70-34 Wear & Non-Wear

80

80

80

neat

modified

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

Tim Clyne 651-234-7350 tim.clyne@state.mn.us www.mndot.gov/mnroad