(中铁十八局集团第二工程有限公司， 唐山 063000)

［摘要］针对不同因素对再生混凝土性能的影响问题，设计正交试验测试不同水胶比、再生粗细骨料掺和比例、粉煤灰掺和比例的再生混凝土的工作性能和力学性能。确定再生混凝土的最优配比，测试该再生混凝土的耐久性，并将其与工作性能、力学性能相近的C40普通混凝土进行对比，通过SEM观测其内部结构，通过压汞法分析其孔隙结构。结果表明：再生混凝土强度影响大小顺序为再生粗骨料掺和比例>水胶比>再生细骨料掺和比例>粉煤灰掺和比例；再生混凝土坍落度影响大小顺序为再生粗骨料掺和比例>粉煤灰掺和比例>水胶比>再生细骨料掺和比例；由于再生粗骨料存在微裂缝，再生混凝土耐久性稍弱于普通混凝土；加大混凝土保护层厚度，增加矿物掺合料掺和比例可以改善再生混凝土耐久性；观察SEM图像可以看到，再生骨料-水泥石界面粘结性质较好，但再生骨料表面有一些微裂缝，分析压汞法结果发现，再生混凝土中100～1 000nm范围内的孔隙数量较多，不利于再生混凝土的耐久性。

［关键词］再生混凝土；正交试验；耐久性；孔结构；压汞法

中图分类号：TU528-79文献标识码：A文章编号：1002-848X(2021)09-0074-05

Analysis of influencing factors on performance of recycled concrete and research on its durability

PENG Yongjun

(China Railway Eighteenth Bureau Group Second Engineering  Co., Ltd., Tangshan 063000, China)

Abstract:In view of the influence of different factors on the performance of recycled concrete, orthogonal tests were designed to test the working and mechanical properties of recycled concrete with different water-binder ratios, mixing ratios of recycled coarse and fine aggregate and fly ash. The optimum mixing ratio of recycled concrete was determined, and the durability of the recycled concrete was tested. The durability of the recycled concrete was compared with that of C40 ordinary concrete with similar working and mechanical properties, and its internal structure was observed by SEM and the pore structure was analyzed by mercury injection method. The results show that: the influence order of recycled concrete strength is recycled coarse aggregate mixing ratio>water-binder ratio>recycled fine aggregate mixing ratio>fly ash mixing ratio; Recycled concrete slump influence order is recycled coarse aggregate mixing ratio>fly ash mixing ratio>water-binder ratio>recycled fine aggregate mixing ratio; The durability of recycled concrete is weaker than that of ordinary concrete.Increasing the thickness of the concrete protective layer and the minerals mixing ratio can improve the durability of recycled concrete; By observing SEM images, the interfacial adhesion between recycled aggregate and cement paste is good but there are some micro cracks on the surface of recycled aggregate. By analyzing the results of mercury injection method, it is found that there are many fine pores in recycled concrete 100～1 000nm, which directly affects the durability of concrete.

Keywords:recycled concrete; orthogonal test; durability; pore structure; mercury injection

作者简介：彭勇军，学士，高级工程师，Email：809897249@qq.com。