Performance of cement asphalt mortar with nanomaterials

Abstract

Deterioration of the cement asphalt mortar (CAM) cushion in non-ballast slab track can decrease the safety of high-speed railway lines in service. The improvement in the performance of CAM due to the addition of nanosilica was investigated in this study. The workability, mechanical properties and fatigue behaviour of CAM with nanosilica were determined and compared to those of CAM without nanosilica. The microstructure of the CAM with and without nanosilica was also observed. The results showed that the CAM workability decreased with the addition of nanosilica, but this could be rectified with the correct dosage of superplasticiser. Furthermore, the rate of decrease in compressive strength and flexural strength with increasing temperature was reduced with the addition of nanosilica. Additionally, the fatigue life of the CAM with nanosilica was longer than that of the CAM without nanosilica. Microstructure analysis confirmed that the area of the free asphalt membrane was reduced, which may be responsible for the improved performance of the CAM.