Huang Yanni, Liu Fengyin, Zhang Xiangtong
School of Civil Engineering and Architecture, Xi'an University of Technology, Xi'an 710048, China.
State Key Laboratory of Water Engineering Ecology and Environment in Arid Area, Xi'an University of Technology, Xi'an 710048, China.
Materials (Basel). 2025 May 27;18(11):2514. doi: 10.3390/ma18112514.
The formation and spatial uniformity of calcium carbonate (CaCO) are critical for evaluating the effectiveness of microbial-induced calcium carbonate precipitation (MICP) in geotechnical applications. In recent years, the single-phase injection method has emerged as a promising alternative to traditional two-phase processes by addressing the issue of uneven CaCO distribution. This study proposes a dual inhibition strategy that delays the mineralization reaction by synergistically lowering pH and temperature, thereby promoting uniform precipitation and enhanced compressive strength in cemented sand columns. A series of experiments, including bacterial growth, aqueous reaction, sand column reinforcement, and microstructural characterization, were conducted. Results show that the minimum pH required for flocculation increases from ~4.5 at 40 °C to ~6.0 at 10 °C. Under dual inhibition, the lag period effectively improved the spatial uniformity of CaCO and enabled complete calcium utilization within 24 h. After four treatment cycles, the CaCO content at 10 °C increased by 53%, and the unconfined compressive strength reached 2.5 MPa, a 50% improvement over the 40 °C condition. XRD analysis confirmed that calcite was the dominant phase (85-90%), accompanied by minor vaterite. These findings demonstrate the adaptability and efficiency of the dual inhibition method across temperature ranges, providing a cost-effective solution for broader engineering applications.
碳酸钙（CaCO）的形成及其空间均匀性对于评估微生物诱导碳酸钙沉淀（MICP）在岩土工程应用中的效果至关重要。近年来，单相注入法通过解决CaCO分布不均的问题，成为传统两相工艺的一种有前景的替代方法。本研究提出了一种双重抑制策略，通过协同降低pH值和温度来延迟矿化反应，从而促进胶结砂柱中的均匀沉淀并提高抗压强度。进行了一系列实验，包括细菌生长、水相反应、砂柱加固和微观结构表征。结果表明，絮凝所需的最低pH值从40℃时的约4.5增加到10℃时的约6.0。在双重抑制下，延迟期有效改善了CaCO的空间均匀性，并在24小时内实现了钙的完全利用。经过四个处理周期后，10℃时的CaCO含量增加了53%，无侧限抗压强度达到2.5MPa，比40℃条件下提高了50%。XRD分析证实方解石是主要相（85-90%），伴有少量球霰石。这些发现证明了双重抑制方法在不同温度范围内的适应性和效率，为更广泛的工程应用提供了一种经济高效的解决方案。
