基于再生骨料多孔界面良好载具性的自修复混凝土长期裂缝修复效能与抗裂机理研究

The project is based on the strategy of recycling and intelligent development of building materials in China, and transforms the research ideas of strengthening the weak interface of recycled aggregates in the past. Instead, it is more reasonable to make intelligent building such as self-healing concrete materials by making use of loose aggregate porous interfaces that are easy to host microorganisms. This method not only solves the problem of unbalanced carrier property and mechanical property when selecting the self-healing concrete carrier, but also reduces the production cost of the two and expands the application range. The project closely revolves around the key element of the interface of recycled aggregates which affects the carrier properties of microbes, the mechanical properties of materials and the internal and external temperature and humidity responses. And then studies the cracking mechanism of self-repairing concrete components under long-term load-environmental erosion-temperature and humidity coupling. It uses interface quantitative parameters corresponding to various interface combinations to comprehensively reflect the microbiological carrier properties, interface micro-thickness, modulus, mechanical time-variation properties in weak areas, and establish artificial simulation environments and materials corresponding to interface forms. According to the temperature and humidity response spectrum of the environment, a long-term temperature and humidity environment test simulation method is proposed to systematically solve the long-term multi-factor coupling effect of this kind of building components crack repair efficiency and crack resistance mechanism. The research results have important scientific significance and engineering application value for simultaneously promoting the sustainable and intelligent development of building materials in China.

项目立足我国建筑材料循环再生与智能化发展战略，改变以往强化再生骨料界面薄弱区的研究思路，而是“扬长避短”利用再生骨料界面疏松多孔易于寄居微生物的良好载具性，制备自修复混凝土这类智能化建材。不仅解决了自修复混凝土载体选择时载具性与力学性不平衡的问题，更是降低了二者生产成本、拓展了应用范围。项目紧紧围绕再生骨料界面这一影响微生物载具性、材料力学性能、内外温湿度响应的关键因素，开展长期荷载-环境侵蚀-温湿度耦合作用下自修复混凝土构件开裂机理研究，采用与多种界面组合形式相对应的界面定量参数，综合反应微生物载具性、界面微观长厚度、模量、薄弱区力学时变性能，建立与界面形式对应的人工模拟环境与材料内环境温湿度响应谱，并依此提出长期温湿度环境试验模拟方法，系统解决长期多因素耦合作用下该类建材构件裂缝修复效能与抗裂机理问题。研究成果对同时推动我国建筑材料可持续化与智能化发展具有重要的科学意义和工程应用价值。

项目立足我国建筑材料循环再生与智能化发展战略，“扬长避短”利用再生骨料界面的良好载具性，制备自修复混凝土智能化建材。不仅解决自修复混凝土载体选择时载具性与力学性不平衡的问题，更降低了二者生产成本、拓展应用范围。通过开展微生物自修复再生混凝土制备方法及最优配合比试验研究，系统研究不同界面微生物活性、修复时间、载体粒径、菌液浓度等因素的修复效能，结果表明裂缝宽度为0.2mm时再生骨料粒径小于5mm、菌液浓度40%及载体占比30%的自修复混凝土修复效能最佳；通过开展微生物自修复再生混凝土微观产物及界面粘结强度试验研究，系统分析了修复产物的形貌、成分、生成量、矿化沉积机理与界面的粘附性能，建立了不同界面的粘结机理及粘附力模型；通过开展微生物自修复再生混凝土力学性能试验研究，系统分析了应力-应变曲线模型与力学性能恢复表征，建立了微生物自修复再生混凝土损伤模型，提出了力学性能恢复机理；通过开展微生物自修复再生混凝土干湿循环下抗氯盐侵蚀试验研究，系统研究了干湿循环下氯离子扩散机理及扩散六相数值模型，建立了氯盐侵蚀模型；通过开展长期荷载-环境温湿度-氯离子侵蚀耦合下微生物自修复再生混凝土耐久性与孔隙结构试验研究，系统研究了多因素耦合下微生物自修复再生混凝土内部温度响应、相对湿度响应、氯离子浓度分布的规律与机理，及孔隙结构变化；基于五相复合材料的随机骨料再生混凝土模型，以钢筋锈蚀诱导期为耐久性极限状态，提出了微生物自修复再生混凝土在长期荷载-环境温湿度-氯离子侵蚀耦合下耐久性寿命预测数值模型。以上研究解决了长期多因素耦合作用下该类建材构件裂缝修复效能与抗裂机理问题，研究成果对同时推动我国建筑材料可持续化与智能化发展具有重要的科学意义和工程应用价值。