Utilisation of coarse glass powder as pozzolanic cement—A mix design investigation

Cement production is a highly energy-intensive and environmentally polluting process, however, despite the detrimental effects, the production rates are increasing annually to meet the ever-rising demand. Hence, it is imperative to look out for materials that can be used in place of cement for promoting green construction and sustainability. On the other hand, glass, post-consumption, is dumped in landfills instead of recycling due to factors such as high recycling cost, cheap imports and lack of awareness to name a few. Since glass is a non-biodegradable material, the practice of dumping waste glass in the landfills is environmentally unsustainable. Recently it has been revealed that glass at particular fineness exhibits pozzolanic characteristics. The focus of this study is to investigate the pozzolanic attribute of a coarse glass powder (≤150 µm) used as a cement replacement; the substitution levels employed were 15% and 30% by weight of cement. In addition to the basic compressive strength testing, durability tests such as drying shrinkage, resistance to chloride ion penetration and heat of hydration were evaluated. The test results indicate that 30% is the ideal replacement level, providing a strength activity index (SAI) of 117%, a 32% higher resistance to chloride ion permeability and a 24% reduction in heat from hydration.