Precipitation of calcium carbonate crystals caused by the metabolic activities of certain microorganisms is a relatively new method which can improve the properties of concrete and repair concrete cracks. The present study investigated the effects of Sporosarcina pasteurii bacteria on healing cracks, compressive strength, tensile strength, ultrasonic pulse velocity, electrical resistivity and microstructure of concrete containing various percentages of limestone powder and natural zeolite. Experimental results show that the microbial calcite precipitations enhanced compressive strength, tensile strength, ultrasonic pulse velocity and electrical resistivity of all specimens at all ages. The maximum values of these parameters are related to the bacterial specimen containing 10% zeolite without limestone powder. The SEM images of the specimens show that the amount of calcite crystals in the bacterial treated specimen containing limestone powder is more than the specimen without that. In addition, crack healing of the specimen containing limestone powder was also slightly better than the specimen without that. The results of Fourier-Transform Infrared spectroscopy show that the precipitation formed at crack surfaces of specimens is CaCO₃.

由某些微生物的代谢活动引起的碳酸钙晶体的沉淀是一种相对较新的方法，可以改善混凝土的性能并修复混凝土裂缝。本研究调查了Sporosarcina pasteurii的影响细菌对愈合裂缝，抗压强度，抗张强度，超声脉冲速度，电阻率和包含不同百分比的石灰石粉和天然沸石的混凝土微观结构的影响。实验结果表明，微生物方解石的析出可以提高所有年龄段样品的抗压强度，拉伸强度，超声脉冲速度和电阻率。这些参数的最大值与含有10％沸石而无石灰石粉末的细菌标本有关。样品的SEM图像显示，经过细菌处理的含石灰石粉末的样品中方解石晶体的数量要多于不含石灰石粉末的样品。另外，含石灰石粉末的试样的裂纹愈合也略好于不含石灰石粉末的试样。₃。