Performance of Ultra-High Volume Fly Ash Cement Pastes with Silica Fume Addition

The utilization of silica fume (SF) construction materials is currently regarded as one of the solutions to achieve not only better material properties but also environmental benefits. In this study, different proportions of SF were used to modify the performance of ultra-high-volume fly ash cement pastes (UHVFP). The effects of SF contents on the porosity, drying shrinkage, compressive strength, water absorption, and chloride ion penetration of UHVFP prepared with a water-to-binder ratio of 0.3 were investigated until 120 days. The results showed that the higher SF content (up to 15%) significantly contributed to the reduction of porosity and limitation of the drying shrinkage of UHVFP samples. It was also found that the later compressive strength of UHVFP containing SF was continuously improved with increasing the SF dosage compared to that of the UHVFP without SF inclusion. Besides, both water absorption and chloride ion penetration of the UHVFP incorporating SF were enhanced up to 120 days in comparison with the control samples.