内掺微生物水工混凝土的早期强度和微观特征

混凝土裂缝的微生物自修复是近年来国内外研究的热点之一。为研究内掺矿化微生物对水工混凝土早期抗压强度和微观孔隙特征的影响，以科氏芽孢杆菌为矿化微生物，乳酸钙为营养物质，进行不同内掺微生物浓度的水工混凝土抗压试验，分析内掺微生物浓度对水工混凝土抗压强度的影响规律，通过氮吸附和扫描电镜分析测试，从微观角度研究内掺微生物对水工混凝土微孔结构及微观形貌的影响。试验结果表明：内掺微生物对水工混凝土抗压强度有明显改善，随着内掺微生物浓度的增大，混凝土抗压强度增幅呈先大后小的趋势，当微生物浓度为9.8×107 cells/cm3时，混凝土的抗压强度增幅最大，28 d抗压强度增加13.1%；微观测试发现，内掺微生物能有效提高水工混凝土胶凝材料浆体的均匀致密程度，改善了混凝土的内部结构，进而使内掺矿化微生物的水工混凝土抗压强度显著提高。

Study on early strength and micro-pore characteristics of hydraulic concrete with mineralized microorganisms

Microbial-based self-repair of concrete cracking is a research hotspot in China and abroad in recent years. This study uses Bacillus Coriolis as the mineralizing microorganism and lactic acid calcium as a nutrient to study the effect of mineralizing microorganisms on the early compressive performance and microscopic pore characteristics of hydraulic concrete. We conduct compressive tests on the concrete with different microbial concentrations, and observe the variation trends in compressive strength. Nitrogen adsorption and scanning electron microscopy are adopted to study microscopically the effects of microbes on pore water, microporous structure, and micro morphology of industrial concrete. The test results show that the compressive strength can be significantly improved by mixing microorganisms; with the increase in microorganism concentration, it shows a trend of increasing first sharply and then mildly. It has a peak at the microorganism concentration of 9.8×107cells/cm3 after an increase in the 28 d strength by 13.1%. Our microscopic observations reveal the microbes can effectively elevate the density and its uniformity of hydraulic concrete cement paste and improve the internal structure, thus significantly raising the compressive strength of the concrete mixed with mineralized microorganisms.