Development of geopolymer concrete made from bagasse ash and calcined water supply sludge

Abstract

This research aims to develop geopolymer concrete from waste materials. Bagasse ash from the sugar industry was used as source material. Since the bagasse ash (BA) contains a lot of silica but small amount of alumina. The calcined water supply sludge waste (WS) was compiled in the mixture to compensate the alumina. Bagasse ash and calcined water supply sludge were ground until their particle size retained on a standard sieve No. 325 less than 5% by weight. Bagasse ash was replaced by calcined water supply sludge in the rage of 5-7.5% by weight. The alkaline to binder materials ratio (AL/B) were between 0.50 -0.70. Two types of 3/8 inch coarse aggregates were used, crushed limestone and basalt. It was found that the effect of replacing bagasse ash with calcined water supply sludge resulted in a geopolymer concrete with compressive strength higher than 185-317 ksc. The higher AL/B ratio increases the workability of geopolymer concrete, but tended to affect the decreasing of compressive strength. Moreover, it was found that the coarse aggregate type had a significant effect on the compressive strength of the geopolymer.