不同粗骨料粒级对混凝土长期性能的影响

The influence of different coarse aggregate particle sizes on the long-term performance of concrete

摘要

依托引江济淮工程，研究不同粗骨料粒级对混凝土长期力学性能、耐久性能及微观结构的影响。研究结果表明：当水胶比为0.42时，5.0~31.5 mm和5.0~40.0 mm粒级粗骨料混凝土的长期性能均较好。与5.0~40.0 mm粒级粗骨料混凝土相比，5.0~31.5 mm粒级粗骨料混凝土的抗压强度和劈裂抗拉强度更大，并且其120 d和180 d的抗压强度增长率分别为12.7%和22.4%,120 d和180 d的劈裂抗拉强度增长率分别为2.7%和4.5%。此外，5.0~31.5 mm粒级粗骨料混凝土的抗渗性能和抗冻性能更佳；5.0~31.5 mm粒级粗骨料混凝土的孔隙率更低，并且其有害孔和多害孔分布较少；5.0~31.5 mm粒级粗骨料粒级混凝土的整体结构更密实，水化产物更为致密。因此，5.0~31.5 mm粒级粗骨料混凝土的性能满足且优于5.0~40.0 mm粒级粗骨料水工混凝土的性能要求，可在水利水电工程建设中充分利用当地粗骨料资源。

Abstract

The influence of different coarse aggregate particle sizes on long-term mechanical properties, durability and microstructure of concrete is studied based on Yangtze-to-uaihe Water Diversion Project. The results show that the long-term performance of coarse aggregate concrete with 5~31.5 mm and 5~40 mm particle sizes is excellent when the water-binder ratio is 0.42. Compared with coarse aggregate concrete with 5-40 mm particle size, the compressive strength and splitting tensile strength of coarse aggregate concrete with 5~31.5 mm particle size are greater, and growth rates of compressive strength at 120 d and 180 d are 12.7% and 22.4%, respectively. The growth rates of splitting tensile strength at 120 d and 180 d are 2.7% and 4.5%, respectively. Moreover, impermeability and frost resistance of coarse aggregate concrete with 5~31.5 mm particle size are better than that with 5~40 mm particle size. The porosity of coarse aggregate concrete with 5~31.5 mm particle size is lower than that with 5-40 mm particle size. And the distribution of harmful pores and multiple harmful pores of coarse aggregate concrete with 5~31.5 mm particle size is less. The overall structure and hydration products of coarse aggregate concrete with 5~31.5 mm particle size are denser. Therefore, the performance of coarse aggregate concrete with 5~31.5 mm particle size is better than coarse aggregate hydraulic concrete with 5~40 mm particle size, which can make full use of local coarse aggregate resources in the construction of water conservancy and hydropower projects.

关键词

粗骨料粒级 / 混凝土 / 力学性能 / 耐久性能 / 微观结构

Key words

coarse aggregate particle size / concrete / mechanical properties / durability / microstructure

基金资助

安徽省引江济淮集团有限公司科研项目“5 ~ 31. 5 mm 粒级粗骨料在引江济淮工程水工混凝土中的应用研究”(YJJH-ZT-ZX-20210408381)