摘要
聚乙烯醇(PVA)纤维能抑制混凝土裂缝扩展,但抑制效果局限于基体内部的微裂缝,对纳米级裂缝的抑制效果甚微.本文研究纳米CaCO_(3)对PVA纤维混凝土静动态劈裂抗拉性能的影响,并通过扫描电镜(SEM)试验分析其增强机理.研究结果表明:纳米CaCO_(3)掺量为1.5%时,PVA纤维混凝土的静动态劈裂抗拉性能显著提高.当养护时间为28 d,纳米CaCO_(3)掺量为1.5%、PVA纤维掺量为0.6%时,与未掺加纳米CaCO_(3)的同掺量PVA纤维混凝土相比,静态劈裂抗拉强度提高了8.6%,在2.25~3.08 s^(-1)应变率下的动态劈裂抗拉强度和耗散能分别提高了11.2%和12.4%.SEM图像分析表明,加入纳米CaCO_(3)能够促进水化产物的生成来填补PVA纤维与基体的结合界面以及水泥基体内部的孔隙和微裂缝,增强纤维与基体之间的黏结度和PVA纤维的阻裂作用,从而提高混凝土材料的静动态劈裂抗拉性能.
Polyvinyl alcohol(PVA)fiber can inhibit the crack propagation of concrete,but the inhibition effect is limited to the micro-cracks inside the matrix and has few effects on nano-scale cracks.The impact of nano-CaCO_(3)on the static and dynamic splitting tensile properties of PVA fiber reinforced concrete was studied in this paper,and the strengthening mechanism was analyzed by scanning electron microscope(SEM)test.The results show that the static and dynamic splitting tensile properties of PVA fiber reinforced concrete are significantly improved when the content of nano-CaCO_(3)is 1.5%.When the curing time is 28 d,the content of nano-CaCO_(3)is 1.5%and the content of PVA fiber is 0.6%,compared with the same content of PVA fiber reinforced concrete without nano-CaCO_(3),the static splitting tensile strength is increased by 8.6%,and the dynamic splitting tensile strength and dissipation energy at 2.25~3.08 s^(-1) strain rate are increased by 11.2%and 12.4%,respectively.SEM image analysis shows that the addition of nano-CaCO_(3)can promote the formation of hydration products to fill the bonding interface between PVA fiber and matrix and the pores and micro-cracks inside the cement matrix,enhance the bonding degree between fiber and matrix and the crack resistance of PVA fiber,thus improving the static and dynamic splitting tensile properties of concrete materials.
作者
康玉梅
李月兰
高雪
黄蔚
KANG Yumei;LI Yuelan;GAO Xue;HUANG Wei(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China)
出处
《湖南大学学报(自然科学版)》
北大核心
2025年第5期162-171,共10页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(U1602232)。
关键词
纳米碳酸钙
聚乙烯醇纤维
动态测试
纤维混凝土
微观结构
nano calcium carbonate
polyvinyl alcohol fiber
dynamic testing
fiber reinforced concrete
microstructure
作者简介
通信联系人:康玉梅(1973-),女,辽宁灯塔人,东北大学副教授,工学博士,E-mail:kangyumei@mail.neu.edu.cn。
