干旱区生态环境知识资源中心

The strength features-of concrete under high temperature, the strength features of structures and the thermal conductivity features, all of which were measured through applying fine sawdust sifted through 5mm screen to the concrete materials. The comparison and analysis of concrete thermal conductivity was performed. For measuring the thermal conductivity in accordance with the ratio of sawdust, a square-shaped test specimen, 30cm x 30cm x 1.5cm, was built. This specimen was deserted from barracks after 24 hours and has gone through curing for 28 days. With this specimen, we analyzed and examined interrelations between the thermal conductivities and each ratio of sawdust with strength of 240kg/ . Consequently, the sawdust added concrete with 1.8% to 2.0% ratio of addition showed thermal conductivity as low as that of insulating materials (0.15W/mk or below) even though it was still higher than that of adiabatic materials. As temperature rises, the strength is observed to fall due to internal crack and minute void phenomenon which in turn results from evaporation of concrete, shrinkage of cement paste and changes in aggregate.