Effect of Combined Glass Particles on Hydration in Cementitious Systems

Abstract

Finely ground glass has the potential for pozzolanic reactivity and can serve as a supplementary cementitious material (SCM). Uniform composition, amorphous nature, and high silica content make ground glass ideal for studying the effects of glass type and particle size on glassy material reactivity at different temperatures. This study focuses on how the combination of glass types and particle sizes affects the microstructure and performance properties of cementitious systems containing glass cullet as a SCM. In this study, the reaction rate, pozzolanicity, and hydration degree quantification of four sets of combined glass types and sizes were investigated using isothermal calorimetry, chemical shrinkage, thermogravimetric analysis (TGA), and analysis of scanning electron microscope (SEM) images. Moreover, compressive strength and water sorptivity were performed on mortar samples to correlate reactivity of cementitious materials containing glass to the performance of cementitious mixtures. Results showed that combined glass can increase reaction rate and exhibit pozzolanic properties, especially when particles of clear and green glass below 25 μm were used at a curing teperature of 50°C. The simultaneous effect of sizes and types of glass cullet (surface area) on reaction rate of glass powder also can be accounted for through a linear addition, reflecting that the surface area would significantly affect glass cullet reactivity. However, performance properties of cementitious systems containing combined glass types and sizes behaved differently, as they followed the weaker portion of the two particles.