Effect of Fly Ash, Bottom Ash, and Silica Fume as Cement Substitutes on Mortar Compressive Strength

Abstract

This research aims to study the effect of fly ash, bottom ash, and silica fume on the compressive strength of mortar. The experimental tests were performed for mortar with six variations in the percentage of cement partial replacement material to investigate its impact on the compressive strength. The cement partial replacement material used in this research mainly came from industrial waste materials. Fly ash (FA), ground bottom ash (GBA), and silica fume (SF) were the waste materials used in this research. Tests were carried out for twenty-eight days for each variation to observe the effect on compressive strength every seven days. The research results show that as concrete ages, its compressive strength increases, with values varying across treatments. At 28 days, compressive strength increased by 11% and 5% in the treatments with 30% FA and 5% SF, respectively. Meanwhile, the BA addition variation did not show a significant increase. The 30% fly ash addition was the variation that showed the largest percentage increase in compressive strength.