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 Por tland cement concrete. It is well known that the silica in glass can b e highly reactive with the alkalis in cement paste and that this react ion can lead to expansion and cracking of the concrete (alkali-silica reaction or ASR). The potential is examined for controlling ASR and ac hieving concrete of suitable strength and durability that uses waste g lass as the aggregate. Laboratory and field research have been complet ed with concrete mixtures designed primarily for paving or flat-work a pplications. Various gradations of glass particle sizes added at vario us 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 aggre gate concrete mixtures that show great promise as well as mixtures tha t fail rapidly. Continued monitoring of the performance of the success ful mixes over a period of several more; years will provide an importa nt step toward defining those situations where waste glass can be used in concrete.