Research Unit in Structural and Foundation Engineering, Department of Civil Engineering, Faculty of Engineering, Thammasat School of Engineering, Thammasat University, Pathum Thani, 12120, Thailand.
Department of Chemical Engineering, Faculty of Engineering, Thammasat School of Engineering, Thammasat University, Pathum Thani, 12120, Thailand.
Sci Rep. 2024 Oct 29;14(1):25947. doi: 10.1038/s41598-024-77339-0.
This research aimed to examine the effects of an acidic environment on the mechanical properties and durability of bio-mortar (BM) encapsulated with Bacillus subtilis bacteria, in comparison to normal mortar (NM). The results at 28 days indicated that both 3% and 6% HCl significantly increased the compressive strength of the BM by 25% and 50%, respectively, compared with that of the NM. However, when 11% HCl was introduced, the compressive strength of the BM decreased to 50% lower than that of the NM. Furthermore, the water absorption rate of the BM was 33% lower than that of the NM. The mass loss for both 3% and 6% HCl was comparable, whereas at 11% HCl, BM experienced a mass loss that was 68% greater than that of NM. These findings suggest that with 3% and 6% HCl, the microbially induced calcium carbonate precipitation (MICP) process effectively generated CaCO, which filled the pores and enhanced the structural integrity of the BM, leading to improved compressive strength and durability. Conversely, at 11% HCl, the MICP benefits in BM were diminished due to adverse environmental conditions that negatively affected the bacterial cells, highlighting the limitations of the HCl concentration for optimizing MICP efficiency in mortar.
本研究旨在考察酸性环境对枯草芽孢杆菌（Bacillus subtilis）包裹的生物砂浆（BM）的机械性能和耐久性的影响，并与普通砂浆（NM）进行比较。28 天时的结果表明，与 NM 相比，3%和 6%的 HCl 分别显著提高了 BM 的抗压强度 25%和 50%。然而，当引入 11%HCl 时，BM 的抗压强度降低至比 NM 低 50%。此外，BM 的吸水率比 NM 低 33%。3%和 6%HCl 的质量损失相当，而在 11%HCl 时，BM 的质量损失比 NM 高 68%。这些发现表明，在 3%和 6%HCl 条件下，微生物诱导碳酸钙沉淀（MICP）过程有效地生成了 CaCO3，这些 CaCO3 填充了孔隙并增强了 BM 的结构完整性，从而提高了抗压强度和耐久性。相反，在 11%HCl 时，由于环境条件对细菌细胞产生不利影响，BM 中的 MICP 益处减少，突出了 HCl 浓度在优化砂浆中 MICP 效率方面的局限性。
