The use of waste glass in concrete : glass powder as cement replacement

Abstract

The depletion of the world's recourses and the generation of surplus quantities of waste material are providing an impetus to examine the use of unconventional materials in construction such as waste glass in Portland cement concrete. Using waste crushed glass (cullet) as aggregate may cause damage to concrete due to expansion caused by the alkali-silica reaction (ASR). The amount of damage caused is strongly related to the size of the glass particles. In fact there exists a certain worst (pessimum) size below which any further decrease in glass particle size improves the concrete properties due to a probable pozzolanic behaviour of glass. The pozzolanicity of finely ground glass cullet can be exploited by using it as a cement replacement in concrete. This study examined the latter by performing compression and flexural strength tests on concrete containing up to 40% cement replacement by glass powder. The possibility of glass colour effect was examined by introduced separately in concrete three different coloured glass consisting of amber, clear and green glass. Results proved that finely ground glass cullet (<300μm) exhibited a higher strength in concrete and no deleterious effects due to ASR. This study justifies the use of waste glass in concrete and encourages the exploitation of other waste materials in the concrete industry. Moreover, waste glass is abundant and much cheaper than cement.