Effects of Hydrated Lime on High-Temperature Rheological Properties of High-Viscosity Modified Asphalt

High-viscosity modified asphalt (HVA) is widely used as the binder for permeable asphalt pavement, and hydrated lime (HL) attracts a strong technical interest as an effective moisture additive in asphalt for a long time. However, the application of HL in HVA has been rarely studied. The present study evaluates the influence of HL on the high-temperature rheological properties of HVA and selects the optimum HL content and fineness. The asphalt mortars of HVA and HL of different contents and fineness were prepared. Temperature scanning (DSR-TS), multiple stress creep recovery (MSCR) by using a dynamic shear rheometer, and scanning electron microscope (SEM) tests were carried out to evaluate the high-temperature rheological properties and microstructure morphology characteristics of the asphalt mortars. Based on the DSR-TS and MSCR tests, the results showed that high-temperature performance together with the ability to deformation resistance of HVA was improved apparently with the increase of the HL content. When the HL content is above 1.2, the stress sensitivity of HVA is lower. The SEM results clearly showed that the uniformity of asphalt mortars could be effectively guaranteed when the HL content was 1.2 and the fineness was 800 mesh. The HL fineness has little effect on the high-temperature performance of HVA. In summary, taking into account the high-temperature performance and microstructure of HVA with HL, the optimum HL content and fineness could be finally determined.