陶粒负载微生物的混凝土开裂自修复研究

摘要

采用多孔陶粒作为微生物载体,在评价修复剂与混凝土基体的相容性以及优选陶粒掺量的基础上,分别从力学性能和耐久性角度对混凝土开裂的微生物自修复进行了研究.结果表明:自修复剂中的牛肉膏和蛋白胨对混凝土有负面影响,而尿素和硝酸钙的影响不大.陶粒体积分数为37.8%时可作为最佳掺量.将微生物芽孢及有机营养组分负载于陶粒中并掺入混凝土,经开裂破坏的试件在28 d养护自修复后,其抗压强度恢复率接近63%,吸水率显著低于基准组,可观察到裂缝被微生物矿化形成的方解石型碳酸钙沉淀填充,裂缝最大修复宽度约为0.51 mm.%Porous ceramsite was used as microbial carrier.Based on the evaluation of compatibility between healing agents and concrete, and an optimal selection of ceramsite content, the self-healing of concrete cracks by bacteria was studied in view of mechanical performance and durability.Results indicate that beef extract and peptone in self-healing agents have a negative effect on concrete, while the effect of urea and calcium nitrate is insignificant.The optimum volume ratio of ceramsite is determined as 37.8%.The ceramsite immobilized with bacteria and organic nutrients is added to concrete.After 28 days curing for self-healing, the recovery ratio of compressive strength of the cracked concrete reaches about 63%, and its water absorption is significantly lower than that of the controlled sample.It can be observed that cracks are filled with calcite type calcium carbonate produced by microbial mineralization, and the maximum crack width can be healed is about 0.51 mm.