蛋壳粉钙源对微生物修复砂浆裂缝效果的影响研究

Experimental study on eggshell powder as calcium source for repairing crack of mortar induced by microbial calcium carbonate precipitation

微生物诱导碳酸钙沉积(MICP)是一种新型的混凝土裂缝修复技术。钙源作为MICP中主要反应物,对MICP修复混凝土裂缝的效果有重要影响。基于固废利用的理念,采用蛋壳粉作为钙源修复砂浆裂缝。对蛋壳粉提取物、醋酸钙、氯化钙和硝酸钙作为MICP钙源修复裂缝后的砂浆进行抗压强度、超声脉冲测试,并对碳酸钙沉淀量进行测定分析,探讨蛋壳粉提取的钙源用于MICP修复砂浆裂缝的可行性。结果表明:蛋壳粉钙源作为修复液组分修复砂浆21 d后,强度修复率为93.81%、相对动弹模为0.824和碳酸钙沉淀量为0.3591 g。相比于传统钙源,将蛋壳粉提取物作为MICP钙源,砂浆裂缝修复后试件的强度和裂缝处碳酸钙沉淀含量更高、结构更致密、完整性更好。

Microbial induced calcium carbonate deposition(MICP)is a new technology for repairing concrete cracks.Calcium source,as the main reactant in MICP,has an important influence on the effect of MICP in repairing concrete cracks.Based on the concept of solid waste utilization,eggshell powder was used as calcium source to repair mortar cracks.The mortar with eggshell powder extract,calcium acetate,calcium chloride and calcium nitrate used as MICP calcium source to repair cracks was tested for compressive strength and ultrasonic pulse,and the precipitation of calcium carbonate was determined and analyzed to explore the feasibility of using eggshell powder extract as calcium source in MICP repair mortar cracks.The results showed that the strength recovery rate reached 93.81%,relative dynamic modulus reached 0.824 and calcium carbonate precipitation reached 0.3591 g after the mortar was repaired for 21 days with eggshell powder calcium source as the component of repair solution.Compared with the traditional calcium source,using eggshell powder extract as MICP calcium source,the strength of the specimen after mortar crack repair and the precipitation content of calcium carbonate at the crack were higher,and the structure was more dense and better integrity.