Evaluation of moisture damage for warm mix asphalt (WMA) containing reclaimed asphalt pavement (RAP)

Abstract Warm mix asphalt (WMA) has attracted a lot of interest and attention from the pavement industry since it was introduced as a potential solution to replace traditional hot mix asphalt (HMA). Although WMA has several advantages over HMA pavements, such as lower fuel consumption and emissions, conclusive answers about the feasibility of this replacement have not yet been provided. One of the main issues with WMA is its susceptibility to damage caused by moisture; so, it needs to be monitored and quantified. It is necessary to investigate the feasibility of using locally accessible materials for this technology. Therefore, locally reclaimed asphalt taken from one of the affected streets will be used and the effect of moisture on WMA will be evaluated using different proportions of this reclaimed asphalt. In addition, three types of mineral filler materials, which are available locally will be used. This research presents an experimental investigation aiming at characterizing the mechanical performance of WMA mixes intended for sustainable pavement construction that contains varying percentages of recovered asphalt pavement (RAP) and natural zeolite. One reference HMA and 12 different types of WMA mixtures made with 0.3% zeolite were tested. For each kind of WMA, three filler types – cement, limestone, and hydrated lime – and different RAP contents – 0, 10, 20, and 30% – were utilized. For each type of mixture, a moisture sensitivity test was conducted to determine its moisture resistance. According to the results, the majority of warm combinations, which contain RAP in their mix, met the AASHTO-mandated minimum tensile strength ratio of 80%, but other mixtures did not, indicating that warm mixtures’ moisture resistance is a cause for worry. However, note that the utilization of RAP in WMA enhanced the behavior aspects of asphalt mixes, such as moisture resistance.