恒温湿循环环境下水泥基材料的体积变形

研究了在20℃、循环湿度变化环境下水泥基材料的体积变形。结果表明:随着湿度的下降,试件水分损失及收缩变形增大,当环境湿度上升时,毛细孔吸湿膨胀,但同一相对湿度下,吸湿过程试件的含水量小于干燥过程的含水量,且试件吸湿膨胀值小于干燥收缩值;从水分损失及收缩速率看,随着相对湿度下降而减小,而在65%~35%区间内其值变化较小;而从湿胀曲线看,其发展趋势相反,开始经历一个平缓期,随后出现加速期;水分损失及收缩变形随着水灰比的降低逐渐减小,不可逆水分及不可逆收缩比重增加,但总的水分损失和残余收缩值仍减少。

Volume deformation of cement-matrix material under constant temperature and humidity cycle

A study was performed to investigate the volume deformation of cement-matrix materials under the condition of relative humidity cyclic at constant temperature of 20 ℃.Some conclusions were drawn as follows: with the decrease of the relative humidity,the moisture loss and shrinkage deformation of specimens increased,while with the increase of environmental humidity,the specimens swelled;under the same relative humidity,the moisture content of the specimens during the moisture adsorption process was less than that during the drying process,and the swelling volume of the specimens induced by moisture adsorption was less than the volume of drying shrinkage;the moisture loss and shrinkage rate of specimens decreased with the decrease of relative humidity,and the variation was relatively small for the range of relative humidity 65%-35%;according to the swell curve during moisture adsorption process,the swelling of the specimens experienced a relatively steady stage at first,and then it entered an acceleration stage;with the decrease of the water cement ratio,the moisture loss and shrinkage deformation gradually decreased,but the ratios of irreversible moisture content and irreversible shrinkage increased,and the total volume of moisture loss and residual shrinkage strain still decreased.