考虑疲劳损伤影响的聚丙烯纤维再生骨料混凝土抗冻耐久性研究

The concrete pavement will not only bear the fatigue damage resulting from frequent traffic load, but also suffer freeze-thaw damage caused by freeze-thaw environment. Fatigue load and coupling of freeze-thaw cycle will intensify the destruction of concrete pavement. From the practical needs of the cement concrete pavement recycling, both of the working conditions and environmental characteristics of pavement engineering are taken into consideration. Microscopic testing of advanced materials technologies are used to study the microstructure of polypropylene fiber reinforced recycled aggregate concrete, and reveal the reinforced or modified mechanism of polypropylene fiber. Through the theoretical analysis and experimental methods, freeze-thaw damage mechanism of polypropylene fiber reinforced recycled aggregate concrete are studied, both of the durability damage mechanism and performance degradation law of polypropylene fiber reinforced recycled aggregate concrete under the coupling action of fatigue load and freeze-thaw cycle are revealed,.Finally, the freeze-thaw damage model of polypropylene fiber reinforced recycled aggregate concrete influencing by fatigue damage is established. This subject will enrich and develop the theoretical study of polypropylene fiber reinforced recycled aggregate concrete. In addition, it can promote the applications of polypropylene fiber reinforced recycled aggregate concrete in repairing road surface, the airport pavement..

混凝土路面不仅要承受频繁交通荷载带来的疲劳破坏，还会遭受冻融环境带来的冻融破坏，疲劳荷载与冻融循环的耦合作用将加剧路面混凝土的耐久性破坏。从水泥混凝土路面再生利用的实际需要出发，考虑路面工程的使用条件及所处环境特点，采用先进的材料微观试验技术，研究聚丙烯纤维再生骨料混凝土细微观结构，揭示聚丙烯纤维对再生骨料混凝土的增强改性机理，通过模拟试验与理论分析相结合的方法，研究聚丙烯纤维再生骨料混凝土的冻融破坏机理，揭示疲劳荷载与冻融耦合作用下聚丙烯纤维再生骨料混凝土的耐久性损伤机理与性能退化规律，建立疲劳损伤影响下的聚丙烯纤维再生骨料混凝土冻融损伤模型。研究成果对丰富和发展纤维再生混凝土理论研究，推动聚丙烯纤维再生混凝土在公路路面、机场跑道等修复中的应用具有重要意义。

随着我国城市规模的不断扩大，大批既有建筑面临拆迁，由此产生的建筑垃圾体量巨大，对废弃建筑垃圾进行回收利用不仅是时代所需，并且对于保护环境、节约资源、发展生态建筑具有重要意义。本项目立足工程实际，深入开展多种纤维混凝土的力学性能及耐久性能试验研究，通过拟合分析，掌握了纤维混凝土力学及耐久性指标间的相关关系；通过试验研究分析了混合再生骨料的材料性能、混合再生骨料混凝土的力学性能、聚丙烯纤维再生骨料混凝土的力学性能，采用先进的XCT断层扫描试验，研究分析了聚丙烯纤维再生骨料混凝土受压破坏过程中的裂缝发展规律，建立了裂缝体积率与荷载值的函数关系；通过快速冻融试验，深入研究了聚丙烯纤维再生骨料混凝土的冻融破坏规律和机理。研究成果对推动聚丙烯纤维再生混凝土在建筑工程、道路工程的进一步应用，丰富和发展纤维增强再生混凝土的理论研究具有重要意义。