Thermal Properties of Concrete Incorporating Glycerin as Phase Change Material Using Response Surface Methodology

Abstract

This study investigates the influence of Glycerin content, water-to-binder (w/b) ratio, and concrete grade on the thermal and mechanical properties of concrete incorporating Glycerin as a phase change material (PCM). M20, M30 and M40 grades of concrete were studied using 0.40, 0.45 and 0.50 w/b ratios. The amount of Glycerin varied from 0 %, 2.5 %, 5.0 %, 7.5 % to 10 % and compressive strength was studied on 7, 28, 56 and 90 days. The slump values decrease with increasing glycerin content, especially at higher w/b ratios, with M20 concrete exhibiting the lowest slump due to its lower grade. Maximum compressive strength is achieved at 5% glycerin content across all mix categories, with a w/b ratio of 0.45 yielding the highest strength. Glycerin content affects the thermal properties, while the w/b ratio significantly influences thermal conductivity. Glycerin content has the most significant impact on thermal diffusivity and specific heat capacity. The interaction between glycerin dose, w/b ratio, and concrete grade is analyzed using Response Surface Methodology (RSM), revealing complex dependencies among these factors. These findings contribute to understanding the behavior of glycerin-modified concrete and provide insights for optimizing its thermal and mechanical properties in construction applications.