气泡混合土抗冻融循环性能试验研究

为解决冻土地区普通路基由于保温性能差导致的路基病害问题，采用保温隔热性能好的气泡混合土作为路基填料，可起到保护冻土、减少病害的作用。为探讨气泡混合土的抗冻性能，选取了不同容重的气泡混合土试件进行冻融循环试验研究，研究气泡混合土质量及强度损失规律，从而获知气泡混合土的容重对其抗冻性能的影响；进而，向气泡混合土试件中掺入玻璃纤维，探讨其对气泡混合土抗冻性能的增强作用。结果表明：气泡混合土的抗冻性能随着容重的增大而提高，表现为容重越大，所能经受的冻融循环次数越多，抗压强度和质量损失率越低；容重为800kg/m3的气泡混合土试件经过15次冻融循环后抗压强度迅速降低，经过100次冻融循环后，试件的质量损失达到9.2%；而容重为1 200kg/m3的气泡混合土试件在经过50次冻融循环后，抗压强度才开始明显降低，经过100次冻融循环后，试件的质量损失只有4.5%。玻璃纤维能显著提高气泡混合土的抗冻性能，其抗压强度损失率和质量损失率明显较未掺纤维的普通气泡混合土要小，且抗压强度和质量损失的速率明显降低；不同容重的气泡混合土试件掺入纤维后，经过50次冻融循环后，试件的抗压强度损失减少50%以上，质量损失减少40%以上。

Experimental Study on Freeze-Thaw Resistance of Foamed Cement Banking

In order to solve the problem of subgrade diseases caused by poor thermal insulation performance of ordinary subgrade in frozen soil area, foamed cement banking with good thermal insulation performance was used as subgrade filler, which could protect frozen soil and reduce disease. In this paper, foamed cement banking specimens with different densities were selected for freeze-thaw cycle test, and the rules of quality and strength loss were studied, in order to learn the impact of density of foamed cement banking on its frost resistance. And then the glass fiber was added into foamed cement banking specimens to test its enhancement effect on frost resistance of foamed cement banking. The results show that the frost resistance of foamed cement banking increases with the increase of its density, which manifests that the higher the density is, the more freeze-thaw cycles can be endured, and the lower the compressive strength and mass loss rate are. After 15 freeze-thaw cycles, the compressive strength of the foamed cement banking specimen with the density of 800kg/m3 decreased rapidly, and after 100 freeze-thaw cycles, the mass loss of the test pieces reached 9.2% while the foamed cement banking specimen with the density of 1 200kg/m3 began to decrease significantly after more than 50 freeze-thaw cycles, and after 100 freeze-thaw cycles, the mass loss of the specimen was only 4.5%. Glass fiber can significantly improve the frost resistance of foamed cement banking. The rates of compressive strength and mass loss of foamed cement banking with glass fiber are significantly less than that of ordinary foamed cement banking without fiber, and the speeds of compressive strength and mass loss are obviously reduced. With mixing the fiber in the foamed cement banking specimen with different density, after 50 freeze-thaw cycles, the compressive strength loss of the specimen was reduced by more than 50%, and the mass loss was reduced by more than 40%.