Performance and Microanalysis of Cement Asphalt Mortar With Admixture of Coal Fly Ash

In this study, cement asphalt mortars prepared with three different cementitious material were systematically investigated: C1 ordinary Portland cement, C2sulfoaluminate cement, C3 (sulfoaluminate: ordinary Portland cement: fly ash=3:6:1) according to the technical indices of cement asphalt mortar for Chinese high speed railway (CRTS II). The C2 CA mortar shows early strength due to the early hydration process between the sulfoaluminate cement and water while the workability is not as excellent as C3 group which not only shows great performance in physical and mechanical properties but also has a good fluidity and workable time to meet the requirement of CRTS II. Through the microstructure analysis, it was found that cement asphalt mortar is a porous structure and the hydration between cement and free water happened at the early age while an integrated formed amorphous gel play an important role in the strength development of the CA mortar as the strength development to 28 days.