Effects of Microencapsulated Phase Change Material on the Behavior of Silty Soil Subjected to Freeze–Thaw Cycles

Abstract

Freeze–thaw (F-T) cycles are one of the most important factors affecting the performance of silty soils with high kaolin content in seasonally freezing regions. This study investigates the improvement of a high-plasticity clayey silt soil (MH) with microencapsulated phase change material (mPCM) to prevent changes in mechanical properties when subjected to freeze–thaw cycles. Unconfined compression, one-dimensional compression, and freeze and thaw tests were performed to evaluate the behavior of treated soil under different freeze/thaw cycles and with different mPCM ratios. It has been observed that the mPCM additive decreased the unconfined compression strength (UCS); however, the strength of the soil held constant during the increasing F-T cycles, and the increase in the mPCM additive content increased the strength of the soil. The inclusion of mPCM affected the compression of the soil and increased settlement (∆H), although the settlement remained constant with increasing freeze–thaw cycles. It has been noted that the compression behavior, which is least affected by the unconfined compressive strength and freeze/thaw cycles, is achieved with the addition of 10% mPCM. As a result of the tests, it was determined that the most suitable additive mPCM ratio is 10% for the compression and strength behaviors.

Study on Shear Characteristics of Herbs Plant Root–Soil Composite System in Beiluhe Permafrost Regions under Freeze–Thaw Cycles, Qinghai–Tibet Highway, China

“…Gençdal et al (2023) reported that their study investigated the improvement of a high-plasticity clayey silt soil (MH) with microencapsulated phase change material (mPCM) to prevent changes in mechanical properties when subjected to freeze-thaw cycles. As a result of the tests, it was determined that the most suitable additive mPCM ratio is 10% for the compression and strength behaviors [62]. Adding modified materials to F-T cycles soil samples can prevent the development of tensile cracks in soil during loading.…”

“…Adding modified materials to F-T cycles soil samples can prevent the development of tensile cracks in soil during loading. The presence of modified materials can enhance the friction between soil particles and enhance the physical and mechanical properties of soil [58][59][60][61][62]. When the improved material was plant roots, Liu et al (2018) observed the microstructure characteristics of the soil surface contacted by plant roots by scanning electron microscopy and obtained that the surface morphology of the soil contacted with the roots showed relatively flat and dense characteristics compared with the rootless soil [63].…”