再生混凝土冻融破坏研究进展

Research progress on freeze-thaw damage of recycled concrete

粉碎旧混凝土作为骨料制作再生混凝土是实现建筑垃圾资源化利用的有效途径。由于再生骨料中存在的微裂缝以及附着的旧砂浆所导致的高吸水率及多重界面性,使得再生混凝土的抗冻性能较普通混凝土更差,限制了其在严寒地区的推广应用。介绍了再生骨料混凝土在冻融循环作用下的破坏机理,综述再生骨料的品质和掺量、矿物掺合料的种类和数量、水灰比因素等对再生骨料混凝土抗冻融性能的影响规律,随后探讨相应的改善技术措施,最后结合现有研究提出了再生混凝土抗冻耐久性研究还需解决的一些问题。

Crushing old concrete as aggregate to produce recycled concrete is an effective way to realize the resource utilization of construction waste. Due to the micro cracks in recycled aggregate and the high water absorption and multiple interfaces caused by the attached old mortar, the frost resistance of recycled concrete is worse than that of ordinary concrete, which limits its popularization and application in severe cold regions. This paper introduces the destruction mechanism of recycled aggregate concrete under freeze-thaw cycle, summarizes the influence of the quality and amount of recycled aggregate, the type and amount of mineral admixtures, water cement ratio and other factors on the freeze-thaw resistance of recycled aggregate concrete, and then discusses the corresponding technical measures to improve the freeze-thaw resistance of recycled aggregate concrete. Finally, combined with the existing research, it puts forward some problems that need to be solved in the research of freeze-thaw resistance durability of recycled aggregate concrete.