Effect of Elevated Temperatures on Compressive Strength of High Volume Fly Ash Concrete

Fly ash concrete is finding upcoming applications in concrete industry due to its strength and durability of concrete.?For the effective utilization of fly ash in the construction of buildings, fly ash concrete structural members have to satisfy fire resistance requirements specified by building codes? [1]. The majority of the experimental work carried out on HVFA concrete is on mechanical properties like strength, durability etc at normal conditions. The recent awareness towards fire protection requires the mechanical behavior and better understanding of HVFA concrete at elevated temperatures. Total of 150concrete cubes, 100mmx100mmx100mm size were cast and cured for 28 days, out of which 75cubes cast with OPC concrete and other 75cubes with HVFA concrete. The water to cement ratio was adopted on the basis of preliminary investigation [14]. The main test parameters involved were high volume fly ash, temperatures exposure from 1000 Cto 8000 C temperature, for 1hour, 2hours, and 3hours duration of exposure is considered. Thereafter the specimens brought to room temperature were tested identically for compressive strength study. The test results have shown that the compressive strengths of all the heated specimens were less than the strengths of companion cubes. The OPC concrete retained slightly more strengths than HVFA concrete cubes for 1 hour duration. However, for 2hours duration of exposure the residual strength variation is similar for both concretes. At 3-hour duration of exposure HVFA concrete cubes showed almost equal strengths but HVFA performed better than OPC concrete at all temperatures