Potential for using waste glass in Portland cement concrete

Local recycling pressures are providing an impetus to examine the use of unconventional materials in construction such as waste glass in Portland cement concrete. It is well known that the silica in glass can be highly reactive with the alkalis in cement paste and that this reaction can lead to expansion and cracking of the concrete (alkali-silica reaction or ASR). The potential is examined for controlling ASR and achieving concrete of suitable strength and durability that uses waste glass as the aggregate. Laboratory and field research have been completed with concrete mixtures designed primarily for paving or flat-work applications. Various gradations of glass particle sizes added at various fractions of total aggregate content have been studied. Compressive strength and wet prism expansion are two of the parameters monitored. The study has spanned several years and has revealed both glass aggregate concrete mixtures that show great promise as well as mixtures that fail rapidly. Continued monitoring of the performance of the successful mixes over a period of several more; years will provide an important step toward defining those situations where waste glass can be used in concrete.