Evaluation of Stone Matrix Asphalt Designed with Untreated Recycled Concrete and Asphalt Pavement Aggregates

Flexible pavements experience a number of distresses during their life cycles, such as cracking and deformation. To lessen the damage, more resilient road mixtures were developed, like Stone Matrix Asphalt (SMA) which is categorized as a gap-graded mixture. However, this resulted in increased construction costs, which had an impact on the growing trend of long-lasting, reasonably priced, and environmentally friendly pavements. The amount of waste generated worldwide is largely attributed to construction and demolition waste (CDW). One practical way to reduce the impact on landfills and maintain the usage of natural aggregates is to employ CDW in pavement construction. The sustainable alternative of combining natural aggregates (NA) with both recycled concrete aggregate (RCA) and recycled asphalt pavements (RAP) was taken into consideration in this study to promote the use of CDW in applications involving heavy traffic pavement. The mix design approach was employed to optimize SMA mix designs incorporating 0%, 10%, 20%, and 30% RCA+RAP. The results of the volumetric characteristics showed that the density, optimum binder content, voids filled with asphalt (VFA), and voids in mineral aggregates (VMA) generally reduced nonlinearly as the RCA-RAP contents increased. The highest stability was seen with 0% RCA+RAP, which was followed by 30%. All blends had acceptable flow values, which ranged from 3 to 4 mm. The 30% RCA+RAP concentration produced the best results in performance tests like the indirect tensile strength and indirect tensile stiffness modulus. According to this study, SMA mixes with the right amount of RCA and RAP can function just as effectively as traditional SMA mixes. Additionally, repurposing construction waste into aggregates for pavement layers can help with better waste management while safeguarding the environment and natural resources.