PERFORMANCES AND MECHANISM OF COMPLEX GEOPOLYMERS PREPARED FROM THERMALLY-TREATED SLUDGE AND HIGH-CALCIUM FLY ASH

Abstract:

Compared to the ordinary Portland cement, geopolymer is a new type of cementitious material which is a low carbon, energy and natural sources saving material. In this paper, the feasibility of a complex geopolymer prepared from high-calcium fly ash and thermally-treated sludge was studied, and the performance and mechanism of the geopolymer were also studied. The results showed that compressive strength of the geopolymer was better when 10% fly ash was replaced by thermally-activated sludge (<45 m) at 900℃ for 1 hour. In complex geopolymeric matrix, amorphous geopolymeric gel covered around spherical fly ahs granule, the Zeolite-like mineral formed, meanwhile, the asymmetric stretching Al-O/Si-O bonds and Si-O-Si/Si-O-Al bending band appeared. This work is beneficial for extending raw materials of geopolymer, and also for utilizing of multi industrial wastes, especial the wastes containing silicate-aluminum phase and calcium.