苎麻纤维对再生混凝土力学强度的影响  

Effect of Ramie Fiber on Mechanical Strength of Recycled Aggregate Concrete

作　　者：阎杰 邢国斌 冯龙辉 梁重阳 谢军 翁维素 白启敬 YAN Jie;XING Guobin;FENG Longhui;LIANG Chongyang;XIE Jun;WENG Weisu;BAI Qijing(School of Civil Engineering,Hebei University of Architecture,Zhangjiakou 075000,China;Hebei Key Laboratory of Diagnosis,Reconstruction and Anti-Disaster of Civil Engineering,Zhangjiakou 075000,China)

机构地区：[1]河北建筑工程学院土木工程学院,张家口075000 [2]河北省土木工程诊断、改造与抗灾重点实验室,张家口075000

出　　处：《硅酸盐通报》2025年第2期455-462,共8页Bulletin of the Chinese Ceramic Society

基　　金：2023年度张家口市科技局指导项目(2322145D);2024年河北省建设科技研究指导性计划项目(2024-2187,2024-2188);河北省科技厅科技支撑计划项目(20373802D)。

摘　　要：为改善再生混凝土(RAC)的力学性能,在混凝土中掺入苎麻纤维(RF),研究了再生粗骨料(RCA)、RF对混凝土抗压强度、抗折强度和抗劈裂强度的影响,通过氮吸附法、扫描电子显微镜分析进一步探究掺入RF对混凝土性能的影响规律和改善机理。再生骨料混凝土力学性能随RF掺量增加呈先升高后降低趋势。RCA取代率为30%(质量分数)时,掺入0.5%(体积分数)RF较未掺RF的混凝土抗折强度提高11.5%。由微观分析可知,RF较高的吸水率可以使纤维表面的水泥浆体产生水化反应,生成的水化硅酸钙凝胶填充孔隙进而增加混凝土抗压强度。但在搅拌混凝土时RF易产生团聚现象,形成薄弱区,增加内部缺陷,抑制抗压强度提高,RF的掺入对混凝土抗压强度的提高较小。RF表面粗糙且有竖向条纹,可增加混凝土裂缝两侧的黏结强度,在混凝土裂缝两侧起桥接作用,限制混凝土受拉荷载作用下裂缝的开展,使混凝土抗折强度和抗劈裂强度有较大提高。In order to improve the mechanical properties of recycled aggregate concrete(RAC),ramie fiber(RF)was added into the concrete.The effects of recycled coarse aggregate(RCA)and RF on compressive strength,flexural strength and splitting strength of concrete were studied.The effects of RF on concrete properties and the improvement mechanism were further explored through nitrogen adsorption method and scanning electron microscope analysis.The mechanical properties of recycled aggregate concrete firstly increase and then decrease with the increase of RF content.When the replacement rate of RCA is 30%(mass fraction),the bending strength and splitting strength of the concrete with 0.5%(volume fraction)RF is 11.5%higher than that without RF.It can be seen from the microscopic analysis that the high water absorption rate of RF can make the cement paste on the fiber surface produce hydration reaction,and the generated hydrated calcium silicate gel fills the pores and thus increases the compressive strength of concrete.However,RF is prone to agglomerate when mixing concrete,forming weak areas,increasing internal defects,and inhibiting the improvement of compressive strength.The addition of RF has a relatively small effect on the improvement of compressive strength of concrete.RF surface is rough and has vertical stripes,which increases the bond strength of both sides of concrete cracks,acts as a bridge on both sides of concrete cracks,limits the development of concrete cracks under tensile load,and can greatly improve the flexural and splitting strength of concrete.

关 键 词：再生混凝土 苎麻纤维 再生粗骨料 抗压强度 抗折强度 抗劈裂强度 微观分析 

分 类 号：TU528[建筑科学—建筑技术科学]