基于膨胀珍珠岩固载微生物的裂缝自修复混凝土劈裂抗拉强度试验研究

混凝土构件内部或表面难以避免出现裂缝,裂缝的产生会导致其耐久性降低。基于膨胀珍珠岩固载微生物的裂缝自修复混凝土具有良好的裂缝自修复能力,有效降低混凝土的维护费用。然而,随膨胀珍珠岩掺量的增大,混凝土的力学性能会显著降低。首先考察了膨胀珍珠岩掺量对该混凝土劈裂抗拉强度的降低程度,然后进一步考察了硅灰和聚丙烯纤维对该混凝土劈裂抗拉强度的增强作用。试验结果表明,当膨胀珍珠岩掺量由0增加到90%时,混凝土的劈裂抗拉强度降幅达62.1%;掺入硅灰可以明显提高该混凝土的劈裂抗拉强度,当硅灰掺量由0增加到10.5%时,混凝土的劈裂抗拉强度增幅达25%;掺入聚丙烯纤维也可以显著提高该混凝土的劈裂抗拉强度,当聚丙烯纤维掺量由0 kg/m^3增加到1.8 kg/m^3时,混凝土的劈裂抗拉强度由1.94 MPa增加到2.55 MPa,增幅为31.4%。

Experimental study on splitting tensile strength of crack-healing concrete based on immobilizing bacteria in expanded perlite

It is difficult to avoid cracks inside or on the surface of concrete members.The presence of cracks in concrete can lead to a decrease in the durability.Self-healing concrete based on immobilizing bacteria in expanded perlite can exhibit excellent crack healing capacity and effectively reduce the maintenance cost of cracks.However,the mechanical properties of concrete will decrease significantly as the volume percentage of expanded perlite increases.In this study,the decrease degree of the splitting tensile strength of the concrete caused by incorporated in expanded perlite was firstly investigated.Then,the strengthening effects of the silica fume and polypropylene fiber on the splitting tensile strength of the concrete were investigated.It shows that the splitting tensile strength of concrete decreased by 62.1%if the volume percentage of expanded perlite was increased from 0 to 90%.Moreover,the incorporation of silica fume could significantly enhance the splitting tensile strength of concrete.The splitting tensile strength of concrete increased by 25%if silica fume proportion was increased from 0 to 10.5%.In addition,the incorporation of polypropylene fiber could also significantly enhance the splitting tensile strength of the concrete.The splitting tensile strength of concrete increases by 31.4%(from 1.94 MPa to 2.55 MPa),if the polypropylene fiber content was increased from 0 kg/m3 to 1.8 kg/m3.