Strength and Workability of Concrete Incorporating Volcanic Ash as a Partial Replacement for Cement

The use of volcanic ash as a partial replacement for cement in concrete mix is explored in this study. The objective of the research was to determine the strength and workability of volcanic ash-based concrete. The parameter of the study was the amount of volcanic ash (0%—control, 15, 25, and 35%) used as a replacement for cement. Compressive strength tests of concrete were performed at 7, 14, 28, and 56 days. Test results indicate that 15% replacement of cement with volcanic ash achieved 90% of the compressive strength of concrete with no volcanic ash after 28 days with almost 75% of strength gain occurring in 7 days. Concrete with 25% and 35% replacement of cement with volcanic ash achieved 80% and 77% strength of the control specimen, respectively. Concrete incorporating volcanic ash as a partial replacement for cement exhibited sustained gain in compressive strength even after 28 days. Specifically, concrete prepared with a 15% volcanic ash replacement achieved higher compressive strength at 56 days compared to concrete with no volcanic ash. On the other hand, the workability of concrete decreased as the percentage of volcanic ash increased. However, it is noteworthy that the concrete with a 15% volcanic ash replacement demonstrated almost similar workability performance to conventional concrete. The study suggests that incorporating volcanic ash as a partial replacement for cement can be a viable option to reduce the negative environmental impact of cement production.