Effect of inorganic powder hydrated lime on performance of asphalt mortar at medium, high, and low temperature

Abstract

This paper investigated the effects of the grain diameter of inorganic powder particle hydrated lime and the aging of asphalt on the properties of asphalt mortar. The Dynamic Shear Rheological Test, Multiple Stress Creep Recovery Test, and Bending Beam Rheological Test were applied to evaluate the effects of powder particle size and asphalt aging on medium-temperature, high-temperature creep performance, and low-temperature crack resistance of mortar. The experimental results demonstrated that the anti-fatigue performance of unaged and aged mortar increased as filler particle size decreases. Meanwhile, asphalt aging was beneficial to the fatigue performance of asphalt mortar, especially for the fine filler particles (M3). However, with the decrease of particle size and an increase in structural asphalt adsorbed in the mortar, the high-temperature performance of aged and unaged mortar gradually become worse. In addition, with a decrease in particle size and an increase in specific surface area, adsorption of more asphalt reduced the mortar modulus and increased the viscosity. This counterbalanced the deleterious effect on the low-temperature performance of the asphalt mortar. Finally, it was found that the microscopic morphology of aged asphalt mortar, compared with the microstructure of unaged asphalt mortar, presented transition from smooth surface to fold texture, and the fillers of coarse particles of aged asphalt mortar were unevenly distributed.