Waste glass powder as a binder in low carbon cement-based materials

Abstract

The construction sector contributes to the significant consumption of natural resources, the production of large quantities of waste materials. It is a major contributor to greenhouse gases, leading to global warming and climate change mostly due to the production of cement. Globally, waste glass is generated in large quantities but offers opportunities for recycling. In the local scene, it was revealed that the management of glass waste is a continuous challenge. It is often a loss-leader due to the absence of a glass waste recycling plant in Malta which leads to its transportation overseas for its management and recycling to avoid dumping in landfills. Moreover, recycling of glass waste generates a significant carbon footprint due to the high melting point of glass. Furthermore, recycling coloured glass is challenging due to the colour specificity. The aim of this dissertation is to propose solutions to the glass waste problem by studying different types of glass waste present in the local scenario. Their effective utilisation by transforming the waste glass into a powder to be used as a binder in low carbon cement-based materials was investigated. The effects of contamination, colour and heat treatment of the waste glass were addressed in this research. This repurposing of glass waste can potentially reduce the strain of glass waste on local institutions involved in waste management. The various samples of waste glass powder were used as partial cement replacements in paste and mortar. Characterisation testing was conducted on the waste glass powders to determine their properties. The testing of the fresh and hardened properties of paste and mortar samples was carried out in aim of gaining knowledge on the materials’ behaviour. Noticeable trends appeared which showed that waste glass powder, even with contamination, has great potential to be used as a supplementary cementitious material that, in the long run, outperforms the traditional cement construction products, especially when heat treatment at effective temperatures is carried out.