冻融作用下粉煤灰–相变材料对砂土的力学性能影响

Study on Freeze-Thaw Properties of Modified Sand Using Fly Ash Shaped Phase Change Materials

摘要: 相变材料(PCM)具有储存潜热的特性，在相变的过程吸收释放大量潜热，有助于改善土体温度场，缓解土体的冻胀损害。以宁夏地区西干渠渠基土为研究对象，研究冻融循环作用下相变材料和粉煤灰复合相变材料对土体物理、力学性质的影响，对冻融循环后不同掺入量的渠基改良土进行质量损失试验、体积变化试验、SEM扫描电镜试验、无侧限抗压强度试验。结果表明粉煤灰复合PCM的加入较纯PCM土减少了质量损失和体积冻胀，同时提升了土体强度。

Abstract: Phase change materials (PCM) have the characteristics of storing latent heat, absorbing and releasing a large amount of latent heat in the process of phase change, which is helpful to improve the temperature field of soil and alleviate frost heave damage of soil. Taking the foundation soil of the Xiganqu canal in Ningxia area as the research object, the effects of phase change materials and fly ash shaped phase change materials on the physical and mechanical properties of soil under freeze-thaw cycle were studied, and mass loss test, volume change test, SEM scanning electron microscopy test and DSC differential heat scanning test were carried out on the improved soil of canal foundation with different dosages after freeze-thaw cycle. The results showed that the addition of cinder shaping PCM reduced the mass loss and volume frost heaving compared with pure PCM soil, and the enthalpy value increased.