乳酸钙掺量对基于微生物矿化沉积的混凝土裂缝自修复效果的影响

The Effect of Calcium Lactate Proportion for Self-healing Capacity of Cracks on Concrete Based on Microbial Mineralization

基于微生物矿化沉积的裂缝自修复技术能够有效地实现混凝土裂缝的自诊断和自修复;然而,如果混凝土中微生物矿化沉积过程中所必需的营养物质掺量不足,则可能限制其裂缝自修复效果的充分发挥。以科式芽孢杆菌为自修复剂,以膨胀珍珠岩为修复剂载体,研制出一种新型裂缝自修复混凝土。主要考察乳酸钙掺量对基于科式芽孢杆菌矿化沉积的混凝土裂缝自修复效果的影响。试验结果表明,经过修复养护28 d后,研制的自修复混凝土表现出优越的裂缝自修复能力,最大修复裂缝宽度达到0.67 mm,为普通混凝土最大裂缝修复宽度的2.23倍;并且乳酸钙掺量对混凝土裂缝自修复效果影响较大,随着乳酸钙掺量的增加,混凝土的裂缝自修复能力显现出先上升后趋于平稳的趋势,当乳酸钙掺量为胶凝材料质量分数的1.75%时,混凝土的裂缝最大修复宽度达到最大。

The self-healing technique based on microbial mineralization can effectively realize the self-diagnosis and self-healing of concrete cracks. However,if the nutrient which is necessary in the process of microbial mineralization is insufficient,it will hamper the self-healing capacity of cracks on microbial self-healing concrete.Bacillus cohnii and expanded perlite are used as self-healing agent and agent carrier respectively,and a new type of self-healing concrete is proposed. The effect of calcium lactate proportion on crack-healing capacity of microbial self-healing concrete based on microbial mineralization was investigated. It shows that self-healing concrete exhibited better crack-healing capacity compared with normal concrete after cured for 28 days,and the maximum healing width of the self-healing concrete is 0. 67 mm,which is 2. 23 times of the one of normal concrete. In addition,the effect of calcium lactate proportion on crack-healing capacity of self-healing concrete is great,and with the increase of calcium lactate proportion,the crack-healing capacity of self-healing concrete firstly increased and then became stable. The self-healing concrete exhibited maximum repair width when the calcium lactate proportion reached to 1. 75 wt. % of cementitious materials.