Glass-derived sodium silicate used as an activator for cement-free binders to rival commercial sodium silicate

Despite the clear and current dangers of climate change, the production of cement, which has an embodied carbon of approximately 860kg CO2e per 1000kg, continues to grow reaching over 4 billion tonnes annually. Alkali activated materials have emerged as alternatives to cement based binders and have been reported to reduce the carbon emissions by up to 80%compared with cement based binders. However, alkali activated materials require the use of strong alkali activators such as sodium silicate and sodium hydroxide. These chemicals are Sodium silicate is a commodity product and is readily used in a variety of industries making it both expensive and in significant demand. This study seeks to create a glass-derived sodium silicate sourcedfrom waste glass that can rival the commercially available products on the market. The glass-derived sodium silicate could not only reduce the cost of alkali activated materials but would also make use of waste glass avoiding over 925,000 tonnes/year of landfilled glass and could save around 1.23 million tonnes of primary raw materials. The glass-derived sodium silicate developed in this work has been utilised as an activator for alkali activated materials. Mortars made with the glass-derived sodium silicate and commercially available sodium silicate activators have shown comparable compressive strengths. In addition, the glass derived sodium silicate has been purified by filtration resulting in a composition similar to products currently on the market.