• After 400 oC fire, the average residual strength of geopolymer concretes were in the range of 93% and 107%, and that of OPC concrete was 90%. After 650 oC, the residual strength of geopolymer concretes was between 59% and 82%, and that of OPC concrete was 52%. Thus, the geopolymer concrete retained higher percentage of strength than the OPC concrete specimens up to 650 oC. The residual strengths of the concretes ranged from 21% to 29% and 11% to 16% after exposures to 800 and
1000 oC respectively.