无机水泥类脱空修补材料冻融损伤试验研究

Experimental research of freeze-thaw ing damage of mud-jack materials

采用典型无机类压浆材料,并控制其水灰比和含气量分别为0.38、0.44、0.50和1.6%、3.0%、5.0%、7.0%。以试验数据统计分析为基础,总结冻融环境下动弹性模量、抗压、抗折、质量增长率和体积膨胀率的变化趋势。试验结果表明压浆材料的抗压强度、抗折强度、动弹性模量的劣化速率随冻融循环次数的增加呈现出先增大后减小的趋势,而质量变化率和体积膨胀率则不断增加;在冻融循环作用次数相同时,采用高含气量可有效降低抗折强度、动弹性模量的力学损伤,而有效降低抗压强度的损伤则可通过降低水灰比的方法来实现;试件体积膨胀率和质量变化率最大值均在5%以内,这表明压浆材料在冻融循环条件下,具有良好的稳定和密实性。

Choose a kind of typical inorganic grouting material individually,the mixture ratio is 0.38,0.44 and 0.50,the gas content is controlled as 1.6%, 3.0%, 5.0% and 7.0%.Basing on the statistical analysis of a large number of experimental data, summarize dynamic elastic modulus, compressive strength, flexural strength, mass and volume rate changing regularities under freezing and thawing cycle. The test results show that the compressive strength,the flexural strength,dynamic elastic modulus＇ s decay rate with the increase of freeze-thaw cycles showed increased firstly and then decreased,while the rate changing of mass and volume are increasing.In the freeze-thaw cycles at the same content, the higher gas content can reduce flexural strength and elastic modulus＇s damage, while the low water-cement ratio can reduce the compressive strength.The maximum value of the volume expansion rate and the mass change rate of the specimens are within 5% ,which indicates that the grouting material has good stability and compactness under the condition of freezing and thawing cycles.