Abstract:
Glass is widely used by industries to manufacture various types of glass products. One of them is glass bottles. Since these products are single used, a huge number of glass bottles accumulates in landfill every year. Waste glass (WG) can be useful material to be utilized as the sand replacement aggregate in concrete production because a large portion of sand is extracted as raw material which leads to the shortage of this material. One of the main causes of global CO2 emissions is cement production. The application of industrial by-products such as fly ash (FA) and ground granulated blast furnace slag (GGBFS) as cementitious materials helps to mitigate problems related to CO2 emission. This research work evaluates the properties of FA and GGBFS-based geopolymer mortars containing waste glass sand (WGS) and glass bubble (GB). A total of fifteen mixtures were developed to examine the influence of partial substitution of river sand (RS) with WGS (15%, 30%, and 45%) and GB (5% and 7.5%), alkali activator solution to binder (AAS/b) ratio, and water to binder (w/b) ratio. The alkali activators utilized in this experiment were sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). The physical and chemical properties of the binders and aggregates were identified. The laboratory experiments were done to evaluate the fresh, mechanical, and durability qualities of the geopolymer mortar mixtures. It was found that for the w/b=0.35 and AAS/b=0.4, the partial replacement of RS with WGS improves the compressive strength and decreases the drying shrinkage and thermal conductivity of the geopolymer mortar. However, the change of w/b to 0.4 or AAS/b to 0.3 has a detrimental outcome on the characteristics of the mortar. The application of glass bubbles has a negative influence on the thermal insulation parameters of the geopolymer mortar. The utilization of FA and GGBFS helps to reduce expansion due to the alkali-silica reaction (ASR). The results of this work propose that using WGS as partial RS replacement aggregate in geopolymer mortar leads to sufficient mechanical and durability properties.