Research on the Effectiveness of Temperature Control with MPCM Grouting for Cracks in the Earthen Ruins of Gaochang Ancient City

Facing the challenges of temperature gradient-induced soil cracking and delamination in earthen ruins like Gaochang Ancient City, this study develops a novel phase change microcapsule (MPCM) grouting material designed for dual functionality: structural reinforcement and thermal regulation. We systematically evaluated its performance in both aspects. Experimental results demonstrated excellent thermal cycling stability. For instance, the maximum mass loss was only 0.65% after 200 cycles, indicating its reliability for long-term service. Evaluation showed that the material effectively provides structural strength compatible with the original soil. With 15% MPCM content, the compressive strength reached 1.39 MPa. Simultaneously, it effectively mitigates temperature fluctuations, significantly regulating temperature gradients. The MPCM-15 sample, for example, reduced the heating rate by 9.7 °C/h and peak temperature by 6.0 °C compared to the control group. Field application further validated its effectiveness in both restoring structural integrity by filling cracks and significantly reducing temperature gradient effects within the site. This dual-function MPCM grouting offers a promising new technical approach for the sustainable preservation of earthen cultural heritage.