Low-temperature limitations and seasonal applicability of MICP for aeolian sand stabilization on the Qinghai-Tibet Plateau

Aeolian sand poses a significant hazard to engineering infrastructure in cold regions. While Microbial Induced Calcium Carbonate Precipitation (MICP) offers a promising approach for sand stabilization, its efficacy under the low-temperature conditions prevalent on the Qinghai-Tibet Plateau has remained unexplored. This study systematically investigates the MICP process across a temperature gradient from -5℃ to 30℃ using solution tests, bacterial activity assays, penetration strength tests, carbonate content measurements, and microstructural analyses. Results indicate that while bacterial activity declined substantially at lower temperatures—exceeding an 83% reduction at -5℃ relative to the optimum at 20℃–25℃—the calcium carbonate yield in solution paradoxically increased with decreasing temperature. In contrast, the critical engineering properties of treated sand, specifically surface penetration resistance and associated carbonate content, improved markedly with higher curing temperatures. Specimens cured at 20℃–30℃ exhibited 64%–278% greater penetration strength and 49%–86% higher carbonate content than those cured at 5℃–15℃. Microstructural observations further revealed that higher temperatures promoted densely packed, cohesive carbonate precipitates, whereas low temperatures yielded loose, poorly attached crystals. Although the low temperatures characteristic of the Plateau's cold season diminish MICP treatment efficacy, the finding that soil temperatures reach 15℃–20℃ during summer confirms the technique's practical viability for sand control on the Plateau during this period.