含水量对两种配合比水泥砂浆抗拉性能影响的对比试验研究

为研究含水量对水泥砂浆抗拉性能的影响,采用"8"字模试验方法对两种配合比下三种含水量(饱和度分别为0%、50%、100%)共60个水泥砂浆试件进行了单轴拉伸试验。试验结果表明:不同含水量下水泥砂浆的应力应变曲线都为单峰曲线,没有屈服阶段,均表现出脆性材料特征;水泥砂浆的应力随着应变的增加逐渐增大,达到峰值应力后试件发生破坏;随着含水量的增加,水泥砂浆的抗拉强度、峰值应变以及韧性皆呈现出先减小后增大的特点;同完全干燥状态下的水泥砂浆相比,饱和度为50%的水泥砂浆峰值应变、抗拉强度以及韧性分别降低了22%、42%、50%;完全饱和状态下水泥砂浆的峰值应变增大了30%,抗拉强度和韧性分别降低了27%和24%。通过比较两种不同配合比下(水灰比为0. 55和0. 45)水泥砂浆的抗拉性能,发现水灰比不同时,含水量对水泥砂浆抗拉性能的影响相似,验证了试验结果的准确性。

Comparative Experimental on Effect of Water Content on Tensile Properties of Cement Mortar with Two Compounding Ratios

To research the influences of water content on the tensile properties of cement mortar,60 cement mortar specimens with three water contents(saturation levels of 0%,50%,and 100%)of two combination were tested using the"8"test method to carry uniaxial tensile test.The experimental results show that the stress strain curves of cement mortar under different moisture contents are all unimodal curves,and there is no yield stage.All of them show brittle material characteristics;the stress of cement mortar gradually increases with the increase of strain,and the specimens reache the peak stress.With the increase of water content,the tensile strength,peak strain and toughness of the cement mortar all show the characteristics of decreasing first and then increasing.Compared with the cement mortar under completely dry condition,the cement mortar has a saturation of 50%.The peak strain,tensile strength,and toughness are reduced by 22%,42%,and 50%,respectively;the peak strain of the cement mortar at full saturation increases by 30%,and the tensile strength and toughness decreases by 27%and 24%,respectively.By comparing the tensile properties of cement mortar with two different water-cement ratios(0.45 and 0.55),it is found that the water content has a similar effect on the tensile properties of cement mortar when the water-cement ratio is different,which verify the accuracy of the test results.