Comparisons of the resilient moduli of asphalt mixes containing recycled materials through empirical and experimental methods

The stiffness of asphalt mixes is a fundamental property that plays an important role in determining the performance of asphaltpavement under traffic loading. The resilient modulus (stiffness) of asphalt mixes can be either determined using laboratory experiments orpredicted through empirical methods based on asphalt components’properties. This paper characterized the effect of recycled materialsincluding recycled construction aggregate (RCA) and glass on the resilient modulus of asphalt mixes using both an empirical methodand a series of laboratory experiments. In addition, the resilient moduli obtained from different methods for different asphalt mixes werecompared, and the accuracy and reliability of different empirical methods were discussed accordingly. The outcomes indicated that in cases inwhich the value of resilient modulus cannot be obtained experimentally, empirical equations cannot well predict the actual resilient modulus.Furthermore, the addition of RCA and glass at a certain amount was shown to improve the resilient modulus of the asphalt mix. This may beattributed to the basic properties of RCA due to its smaller flakiness index and particle shape compared with virgin aggregates. These twoparameters significantly affected the final performance of asphalt mixes.