Phase-Change Heat Buffering for Uniform Biocementation of Desert Sand

Abstract

The rapid progression of global desertification demands sustainable and effective soil stabilization techniques to mitigate wind erosion and stabilize mobile sand dunes. Microbially induced calcite precipitation has emerged as a promising eco-friendly alternative to traditional chemical binders. However, the extreme diurnal temperature fluctuations characteristic of desert environments pose a severe challenge to this biological process. High daytime temperatures accelerate ureolysis excessively, leading to rapid surface precipitation and the formation of a dense, impermeable crust that prevents deeper penetration of cementation fluids. Conversely, low nighttime temperatures inhibit bacterial metabolic activity, halting the consolidation process. This paper introduces a novel intervention utilizing microencapsulated phase-change materials to provide internal thermal buffering within the sand matrix during the biocementation process. By absorbing latent heat during peak daytime temperatures and releasing it during nighttime cooling, the incorporated phase-change materials maintain the internal soil temperature within the optimal biochemical window for Sporosarcina pasteurii. Through comprehensive experimental column studies simulating desert diurnal cycles, this research evaluates the thermal, biochemical, and geomechanical responses of phase-change buffered desert sand. The results indicate a profound improvement in the spatial uniformity of calcium carbonate precipitation along the depth of the soil columns, accompanied by significant enhancements in unconfined compressive strength and ductility. This study establishes a robust theoretical and empirical foundation for deploying phase-change heat buffering to optimize large-scale biocementation in extreme terrestrial environments.