Performance Evaluation of Stone Matrix Asphalt Mixtures and Low-Temperature Properties of Asphalt Binders Containing Reclaimed Asphalt Pavement Materials Modified with Nanosilica

Abstract

Due to several types of deterioration, such as rutting, fatigue cracking, and thermal cracking, that occur in the structure of pavements, researchers have developed solutions, including constructing pavements with enough resistance against permanent deformation, such as stone matrix asphalt (SMA) mixtures, and delaying the pavements’ deteriorations by modifying asphalt binder with various modifiers such as nanoparticles. To decrease the costs required for the construction of pavements and bring about some environmental advantages, researchers gave suggested the use of reclaimed asphalt pavement (RAP) materials in the construction or rehabilitation of pavements. In this study, SMA mixtures in conjunction with asphalt binders containing 0%, 20%, 30%, 40%, and 50% RAP materials modified with 0%, 2%, 4%, and 6% nanosilica were fabricated, and their performance was evaluated through several tests, including dynamic creep, resilient modulus, moisture susceptibility, semicircular bending (SCB) at the intermediate temperature, and bending beam rheometer (BBR) tests. The results showed that the use of nanosilica with RAP materials increased the rutting resistance of mixtures significantly. Moreover, a remarkable increase in resilient modulus values was observed, which was more evident at 25°C than at 5°C. The contemporaneous addition of RAP materials and nanosilica into SMA mixtures increased the moisture and fracture resistance of mixtures, but the effectiveness of nanosilica in increasing the tensile strength ratio (TSR) of mixtures was undermined when it was used in combination with RAP materials. However, the modification of asphalt binders with nanosilica decreased the low-temperature performance of binders, which was more evident in binders containing RAP binder.