The concrete specimens were tested for compressive strengths at different ages up to 28 days to determine the strength development before exposure to fire. The OPC concrete cylinders were subjected to water curing and the geopolymer concrete cylinders were subjected to two different regimes of steam curing. The geopolymer concrete specimens of group GPN were steam- cured at 60 oC immediately after casting and those of group GPH were given a rest period of 3 days before beginning of the steam- curing at 80 oC. The strength developments of the three types of concrete are shown in Fig. 6. It can be seen from the figure that the rest period and higher curing temperature contributed to an increase in strength of the geopolymer concrete specimens of group GPH as compared to the specimens of group GPN. There was very little gain in strength in the geopolymer concrete speci- mens after completion of the steam curing. As usual, strength of the OPC concrete specimens continued to increase gradually to the age of 28 days. The trends of strength development in the geo- polymer concrete specimens are similar to those observed by Hardjito and Rangan [29].