Glass powder as replacement of cement for concrete - an investigative study

Cement production involves extensive energy absorption and emits huge quantities of CO2 in the atmosphere. The production rates are increasing annually to meet the ever increasing demand with increased energy absorption and CO2 emission. Hence, it is imperative to use materials which can replace use of cement to some extent. Conversely, waste glass is being dumped in the landfills. This practice is environmentally unsustainable since glass is non-biodegradable. Recently it's revealed that glass when grinded to a particular fineness exhibits cementitious properties due to pozzolanic reaction. This paper investigates the fresh, mechanical and durability properties of concretes made with cement replaced by coarse glass powder (<150 mu m) at various replacement levels and employing different curing conditions. The replacement levels employed were 0%, 15%, 30% and 50% by weight of cement, while the curing regimes followed were ambient, Elevated Temperature Curing (ETC) @ 40 degrees C and water. Scanning electron microscopy (SEM) and X-ray fluorescence (XRF) techniques were performed on cement and glass powder to investigate the microstructure and chemical composition of the materials. The initial findings show that 30% is the ideal replacement level as it exhibits quite comparable strengths, better workability and higher resistance to chloride ion penetration compared to the control mix.