Optimum Filler–Bitumen Ratio of Asphalt Mortar Considering Self-Healing Property

Abstract

Asphalt mortar plays an important role in the performance of asphalt mixtures. Up to now, there have been many studies on the properties of asphalt mortar. However, asphalt mortar requires a balanced design that considers the overall performance including self-healing capability. Therefore, this study aims to analyze the effect of different types of filler with varied ratios (0.11, 0.22, 0.33, 0.44, and 0.55) by volume on the performance of the asphalt mortar and mixture. The examined fillers were limestone, fly ash, diatomite, and four types of red mud, which were mixed with bitumen to prepare asphalt mortar. Then, the rheological properties of the asphalt mortar were investigated through viscosity tests and multiple stress creep recovery (MSCR) testing. In addition, this research explores the impact of filler type and its ratio on the cohesion and self-healing performance in dry and water conditions. Furthermore, the Hamburg wheel tracking test (HWTT) was performed to evaluate the moisture-damage and rutting resistance of asphalt mixtures, which consisted of the same selected mortar. The results indicate that pull-off tensile strength after the first failure-healing (F-H) cycle in the water condition has a good linear relationship with the dynamic stability of the asphalt mixture in the HWTT. Moreover, red mud and diatomite can be applied as promising substitute fillers compared with the other examined fillers in this study, but the chemical components need to be carefully selected.