Effects of Calcium Silicate Hydrate Seeding on the Strength and Durability of Calcined Clay Pozzolan Cement

Abstract

This study explores the use of synthesized calcium silicate hydrate (CSH), produced with the sol‐gel method, to enhance the performance of calcined clay pozzolan cement, a lower‐carbon alternative to traditional cement. The synthesized CSH was characterized by x‐ray diffraction (XRD) and Fourier‐transform infrared (FTIR) spectroscopy. The CSH was used as a minor admixture between 1 and 3 wt.% of calcined clay Portland cement. In this study, 30% of the Portland cement was substituted with calcined clay. The test methods that were investigated included compressive strength, absorption, and porosity. Environmental impact assessment was performed on the optimum mix. The results of the study indicated that the CSH was found to improve compressive strength, especially at 3% dosage, which showed the highest strength at 28 days. This optimum mix achieved a 12.6% reduction in CO 2 emissions compared with reference samples. Although increased CSH reduced flowability, it significantly improved durability by lowering water absorption by up to 34% at 3 days and enhancing pore structure, as evidenced by reduced sorptivity. Overall, the synthesized CSH enhanced early strength development and durability, making calcined clay cement a more viable and sustainable option.