摘要
纤维自密实混凝土能显著提高材料的抗拉、抗弯和抗裂等性能,但纤维种类及掺量对材料性能的影响规律和增强机理研究尚不成熟。本文研究了不同配比下碳纤维对自密实混凝土的填充性能、力学性能和微观结构的影响。结果表明:(1)忽略微弱纤维含量(0.5%)的影响,随着碳纤维含量从0.5%增加到2%,碳纤维自密实混凝土的坍落度和流动性有所下降,且在相同纤维掺量下,水泥含量较高的自密实混凝土其坍落度和流动性下降速率更快;(2)自密实混凝土的力学性能指标随着碳纤维比例的增加均表现出先增大后减小的趋势,水泥含量越高时,混凝土强度先上升后下降的转折点对应的碳纤维含量越低;(3)从微观结构分析得出,当碳纤维掺量为0.5%~1.5%时混凝土力学性能总体上呈上升的趋势,得益于纤维在混凝土中的均匀分布;纤维含量过高会形成团聚现象,水泥含量过高会阻碍纤维进入孔隙,均不利于材料性能的提升;(4)从填充性能和力学特性综合考虑,建议纤维的最优掺量为1%。
Self-compacting fiber concrete can significantly improve the properties of materials such as tensile, flexural and crack resistance.However, studies on the influence law and strengthening mechanism of fiber types and content on the properties of materials are still immature.The effects of different carbon fiber ratios on the filling properties, mechanical properties and microstructure of self-compacting concrete were studied.The results showed that:(1) The slump and fluidity of CFRP(Carbon Fiber Reinforced Plastics) decreased with the increase of CFRP content from 0.5% to 2%,ignoring the influence of weak fiber content(0.5%),and the slump and fluidity of CFRP self-compacting concrete decreased faster with higher cement content at the same fiber content;(2) the mechanical properties of self-compacting concrete increase first and then decrease with the increase of carbon fiber ratio.The higher the cement content is, the lower the carbon fiber content corresponds to the turning point of concrete strength rising first and then decreasing;(3) according to the microstructure analysis, when the content of carbon fiber is 0.5%~1.5%,the mechanical properties of concrete generally show a rising trend, which is due to the uniform distribution of fiber in concrete.High fiber content will form agglomeration phenomenon, and high cement content will hinder fiber to enter the pore, which is not conducive to the improvement of material properties;(4) from the comprehensive consideration of filling performance and mechanical properties, it is suggested that the optimal fiber content is 1%.
作者
黎鸣
侯圣均
贾帅动
扶凤姣
李立君
LI Ming;HOU Shengjun;JIA Shuaidong;FU Fengjiao;LI Lijun(China Electric Construction Road and Bridge Group Co.,Ltd.,Beijing 100048,China;Sichuan Tieke New Building Materials Co.,Ltd.,Chengdu 610000,China)
出处
《粉煤灰综合利用》
CAS
2022年第1期102-106,139,共6页
Fly Ash Comprehensive Utilization
关键词
碳纤维
自密实混凝土
材料性能
微观结构
强化机理
carbon fiber
self-compacting concrete
material properties
microstructure
strengthening mechanism
