Despite a critical shortage of virgin aggregate, the availability of demolished concrete for use as recycled concrete aggregate (RCA) is increasing. Using this waste concrete as RCA conserves virgin aggregate, reduces the impact on landfills, decreases energy consumption and can provide cost savings. However, there are still many unanswered questions on the beneficial use of RCA in concrete pavements. This paper looks at the effect RCA has on the coefficient of thermal expansion (CTE) and its impact on pavement performance. CTE is a key property of concrete and relates to the amount of expansion/contraction due to changes in temperature. CTE testing was conducted on 16 cores containing various amounts of coarse RCA (0%, 15%, 30%, and 50%) using a simplified methodology. Testing showed that concreteperformance improved as the amount of RCA increased. This was demonstrated by a decrease in CTE. Values for the CTE ranged from 7.28x10-6 /oC for0% coarse RCA to 4.10x10-6 /oC for 50% coarse RCA. The variability of theCTE results was also examined to assess if the RCA content or simplified testing methodology impacted the results. Performance of the RCA concrete was simulated using the Mechanistic-Empirical Pavement Design Guide (MEPDG). Average, minimum, and maximum CTE values for each RCA amount were usedto investigate the sensitivity of this important property on pavement roughness, cracking, and faulting. Simulated pavement performance of all theRCA sections improved as the CTE values decreased.
Samenvatting