Moisture-Induced Deterioration Mechanism of Asphalt Mortar Using Different Fillers

The effect of different filler types on the properties of asphalt mortar before and after water saturation was studied by laboratory tests. Under both dry and water-saturated circumstances, four alternative fillers, limestone powder, hydrated lime, PO42.5 cement, and brake pad powder, are used, evaluated, and compared. The study methodology included characterizing the micromorphology, while X-ray diffraction imaging analysis and scanning electron microscopy were used to determine the chemical composition of the asphalt mortar following water saturation. To quantify the effects of moisture on the bonding mechanisms, surface energy concepts were employed to compute the surface free energy parameters of the asphalt mortar made with different filler materials. Dynamic shear rheometry was employed in the investigation to describe the rheological characteristics of the asphalt mortar as a function of filler under different water saturation conditions. The bonding strength of the asphalt mortars with various fillers was then quantitatively measured using pullout tests to account for the coupling effects of moisture and temperature. The findings of the laboratory tests generally showed that the asphalt mortar’s effectiveness declined following moisture conditioning and saturation in water. However, hydrated lime, brake pad powder, and cement showed promise in strengthening the bonding of fillers and asphalt, with hydrated lime being superior. Likewise, the asphalt mortar’s ability to tolerate moisture and resist water damage was also generally improved by hydrated lime.