Dynamic Modulus Characteristics of Mixtures Containing Recycled Asphalt Pavements, Warm Mix Additives, and Antistrip Agents

Abstract

Abstract The utilization of reclaimed asphalt pavement (RAP) has proven to be a promising technology to solve some of the environmental issues and resource shortages in many parts of the world. The objective of this study was to investigate dynamic modulus and phase angle of surface type mixtures using two warm mix asphalt (WMA) technologies (i.e., warm mix additive E and foaming), and two liquid antistripping agents (ASAs). A total of 20 mixtures were designed and tested. Viscoelastic master curve modeling, statistical analysis, as well as continuous relaxation spectrums were conducted to obtain a better understanding of the properties of the mixtures. The results implied that RAP or WMA technologies had significant effects on mechanical performances, which should be carefully considered during mix design, but ASA agents, statistically, did not have such effects. In addition, the influence of RAP depended on WMA technology type, and the effects of ASA agents relied on aggregate and RAP source. The rheological index showed that both WMA technologies and ASA materials had negative impacts on the rheological properties of the mixtures, but the addition of RAP mitigates this impact only for mixtures containing ASA additives. Furthermore, the continuous relaxation spectrum confirmed the negative influences of WMA technologies and no obvious effects of ASA materials.