Effect of heat on laterised concrete

This study presents the results of investigation of the effects of temperature variation on the compressive strength of laterised concrete. Cube specimens were cast, cured in water at ambient laboratory temperature and subjected to different temperature regimes before testing. A concrete mix ratio of 2:3:6 (cement: laterite/sand: granite) with water/cement ratio of 0.65 was adopted for this investigation. The laterite content in the fine aggregate was varied from 0 to 100% at 25% interval. Specimens cured for 7 and 28 days were subjected to uniaxial compressive loading tests at room and elevated temperatures of 250, 500 and 750oC. The results show that normal concrete cannot withstand appreciable load above 250oC while laterised concrete with 25% laterite in the fine aggregate is able to resist higher load with increase in age and at temperature up to 500oC. It is also observed that there is no appreciable increase in strength at higher temperatures. The peak compressive strength value of 30.44 N/mm2 is recorded for the mix with 25% laterite-75% sand at 500oC. This is an indication that the strength of laterised concrete is generally sufficient for use at elevated temperature not exceeding 500oC