A novel way to maximize the use of waste glass in alkali activated cement mortar

To maximize the reuse of waste glass in cement based materials, the feasibility of using both crushed glass cullet and milled glass powder in alkali activated cement mortar was explored. This paper reports the findings of an... [ view full abstract ]

To maximize the reuse of waste glass in cement based materials, the feasibility of using both crushed glass cullet and milled glass powder in alkali activated cement mortar was explored. This paper reports the findings of an investigation on the influence of the use of different percentages of waste glass powder and cullet, and two different casting methods on the properties of the alkali activated cement mortars. Ground granulated blastfurnace slag (GGBS), waste glass powder (WGP) were used as precursors at different proportions. Different proportions of waste glass cullet (WGC) were used to replace river sand as the fine aggregate to prepare the cement mortar. The compressive strength, workability of the cement mortar with different percentages of WGP were determined. The influence of WGC on the thermal conductivity and fire resistance was investigated as well. Besides, the expansion due to alkali silicate reaction (ASR) of the glass cement mortar prepared with a dry-mix method and the traditional wet-mix method was compared. Mercury intrusion porosimetry (MIP) was employed to investigate the porosity changes of the mortar samples. The morphology of cement paste was observed using scanning electron microscopy (SEM)/energy dispersive X-ray (EDX). It was found that the cement mortar containing a higher weight percentage of WGP had a lower compressive strength due to the lower activity of WGP compared to GGBS. However, the workability of the cement mortar increased with the increase of WGP dosages as the result of the negligible water absorption of glass. Additionally, the cement mortar incorporating higher percentages of WGC had lower thermal conductivity due to the lower thermal conductivity of glass compared to sand. The results point to the possible improvement of the fire resistance performance of the glass incorporated AAC mortar when compared with those made with conventional cementitious materials and river sand mixes. The cement mortar prepared with the dry-mix method showed better ASR resistance than that prepared with the wet-mix method.