Fire resistance of reinforced concrete columns containing ground rice husk ash

Abstract

This research was to study the fire resistance of reinforced concrete columns containing ground rice husk ash. The designed compressive strengths of control concretes at 28 days were 300, 500 and 700 kg/cm². Rice husk ash was ground until the particles retaining on sieve No. 325 not more than 5% by weight. Portland cement type I was replaced by ground rice husk ash at 0, 10, 20 and 30% by weight. Reinforced concrete columns were cast at size of 0.20x0.20x0.80 m³. The samples were cured at 90 days and burned at 600 °C for 2 hours to test the compressive strength and compared with unburned reinforced concrete columns.  From the experimental result, it showed that the use of ground rice husk ash at 10 and 20% could improve the strength development of concrete at 90 days and were higher than that of control concrete while the use of 30% slightly lower than that one. After burned reinforced concrete columns at 600°C for 2 hours, it was found that the strength of columns were reduced approximately 45% of control columns without ground rice husk ash for all designed strengths. Usage of ground rice husk ash in reinforced concrete columns decreased the strength loss due to burning. The optimum usage of ground rice husk ash was 20% which it provided the strength higher than the burned column approximately 10 to 15%. From the result, it can be concluded that ground rice husk ash can increase the fire resistance of reinforced concrete columns.