Abstract:The mortar specimens were prepared by replacing 0%, 20%, 30%, and 40% of cement with the same amount of fly ash and ceramic polishing powder. The expansion ratio and strength were measured. The microstructure, element composition, and products of interfacial transition zone between aggregate and cementitious material were analyzed by scanning electron microscope(SEM), energy disperse spectroscopy(EDS) and X ray diffraction(XRD). The intrinsic mechanism of alkali silica reaction(ASR) inhibition by fly ash and ceramic polishing powder was studied. The results show that ASR can be effectively inhibited by introduction of fly ash or ceramic polishing powder in mortar bars. Considering the effects of fly ash or ceramic polishing powder on ASR inhibition and the strength, it is recommended that replacement ratio of fly ash or ceramic polishing powder should be 20%30%. The structure of the interfacial transition zone becomes denser. Calcium silicon ratio and sodium silicon ratio significantly decrease in the interfacial transition zone of the material. Because K+ is more likely to bind to Al2O3 than Na+. K and Al are enriched in the interfacial transition zone, which makes potassium silicon ratio and aluminium silicon ratio mutate at the region in the interfacial transition zone. Although the ceramic polishing powder has a higher alkali content, the reaction of the SiO2, Al2O3 in the ceramic polishing powder and the reactive aggregates with Na+ and K+ in the system generates kalsilite(KAlSiO4) and nepheline((K, Na) AlSiO4) in the interfacial transition zone, which are volume stabilized tectosilicate minerals, thus ASR can be inhibited.