ANALYSIS OF THE EFFECT OF FLY ASH SUBSTITUTION WITH SHELL WASTE MATERIAL AND CEMENT ON THE COMPRESSIVE STRENGTH OF GEOPOLYMER MORTAR

Abstract

This study aims to analyze the effect of substituting cement and shell waste from mollusks on the compressive strength of geopolymer mortar. The utilization of shell waste rich in CaO as a substitute for fly ash and cement is expected to enhance sustainability and material efficiency in construction materials. The methodology employed is experimental, with variations in material proportions, including fly ash substitution levels of 10–30% and cement addition of 5–10%. Compressive strength tests are conducted at ages 3, 7, and 28 days following ASTM C109 standards, along with microstructural analysis to understand the interactions among the materials. Results indicate that the optimal combination, achieving the highest strength, is 60% fly ash, 30% shell waste, and 10% cement, with a compressive strength of
41.28 MPa at 28 days. This research supports sustainable development by valorizing industrial waste, reducing reliance on traditional cement, and advancing eco-friendly construction materials.