Mechanical properties evaluation of asphalt mixtures with variable contents of reclaimed asphalt pavement (RAP)

Abstract

This research paper aims to evaluate the performance of hot asphalt mixes containing reclaimed asphalt pavement (RAP) at different percentages. The usage of RAP as a recycled construction material has become a common practice in many countries nowadays. To achieve this objective, experimental tests were conducted on a total of 15 asphalt mixtures prepared with five different contents of asphalt cement, including 3.5, 4, 4.5, 5, and 5.5%. Three Marshall mixes were made for each asphalt content. Following the ASTM standards, Marshall stability and flow tests were performed to determine the optimum asphalt content of each mix tested (i.e., control, 25% RAP, 50% RAP, and 75% RAP mixes, respectively). The results showed an improvement in the stability and flow values with the increase in RAP content. Maximum stability of 15.11 kN was obtained with a 75% RAP mix at 4% asphalt cement content. Notably, as the asphalt content increases, lower air voids values and vice versa, higher voids filled with asphalt were observed for the four tested mixes.

Keywords

• Recycling
• RAP
• Asphalt
• Marshall
• Stability
• Optimum asphalt content