Effects of high temperatures on physico-mechanical characteristics of autoclaved aerated concrete

Abstract

The study aims to determine the compressive strength, as well as linear and volumetric deformations of autoclaved aerated concrete with an average density of 600 kg/m3 after holding at temperatures in the range of 100–800 °C. The compressive strength of test samples was determined using an IP-100 hydraulic press in accordance with the state standard GOST 10180 “Concretes. Methods for determining the strength of control samples” State Standard. It was experimentally established that after holding aerated concrete samples at a temperature of 100 ºС, its compressive strength increased by 6.2 %, which is associated with the loss of an excess moisture during heating. A further increase in the temperature to 600 ºС insignificantly affects its strength characteristics. At an increase in the test temperature to 800 ºС, the residual compressive strength of samples averaged 62.6 % of the control sample strength. Linear dimensions of samples begin to vary at a temperature of 300 ºC and do not exceed 1.56 % of initial values up to a temperature of 600 ºC. A further increase in the temperature to 800 ºС reduces the linear dimensions of aerated concrete samples by 15.15 %. Volumetric deformations of autoclaved aerated concrete samples in the temperature range of 300–600 ºС are less than 5 %, while, for the temperature of 700–800 °С, they range from 25 % to 38.9 %. The studied aerated concrete can withstand high temperatures up to 600 °C without significant variations in its physical and mechanical characteristics.