再生砂浆粉纤维增强水泥基复合材料拉伸及开裂性能研究  

Study on tensile and crack properties of fiber-reinforced cementitious composites with recycled mortar powder

作　　者：吴瑞雪[1] 赵铁军[1] 郭得阳 WU Ruixue;ZHAO Tiejun;GUO Deyang(School of Civil Engineering,Qingdao University of Technology,Qingdao 266033,Shandong,China)

机构地区：[1]青岛理工大学土木工程学院,山东青岛266033

出　　处：《建筑科学与工程学报》2023年第4期24-32,共9页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51778309)。

摘　　要：将建筑垃圾研磨筛分成再生粉(再生砂浆粉、再生混凝土粉等)并替代胶凝材料制备水泥砂浆基体,是建筑垃圾再利用的有效途径。通过扫描电子显微镜对再生砂浆粉(RMP)的微观结构进行观测并利用X射线荧光对RMP的矿物组成进行了测定,将RMP替代水泥(替代率分别为12.5%、25%、50%)制备纤维增强水泥基复合材料(FRCC),研究其单轴拉伸应力应变行为及不同应变状态下裂缝宽度及分布情况。结果表明:相较于水泥,RMP的SiO 2含量较多,而CaO含量相对较少,一定程度上降低了胶凝材料的水化反应和基体强度;RMP粒径分布比水泥更广,较小粒径的颗粒可有效填充基体缝隙,因此当RMP替代率较大时,其对基体强度的影响较小;3种再生砂浆粉纤维增强水泥基复合材料(RMP-FRCC)试件均表现出了优异的应变硬化特性和多缝开裂控制能力,极限应变均达到了8%以上,裂缝分布均匀,极限应变状态下的平均裂缝宽度均在100μm以下;25%的RMP替代水泥可显著增加FRCC的应变硬化特性,但较大的替代率(50%)则会降低其力学性能及应变指标。It is an effective way to reuse construction waste by grinding and screening construction waste into recycled powder(recycled mortar powder,recycled concrete powder,etc.)and replacing cementitious materials to prepare cement mortar matrix.The microstructure of recycled mortar powder(RMP)was observed by scanning electron microscope and the mineral composition of RMP was determined by X-ray fluorescence.RMP was used to replace cement(the replacement rates were 12.5%,25%and 50%,respectively)to prepare fiber-reinforced cementitious composites(FRCC).The uniaxial tensile stress-strain property and crack width and distribution under different strains were studied.The results show that compared with cement,RMP has a higher SiO 2 content and a lower CaO content,which reduces the hydration reaction and matrix strength of cementitious materials to a certain extent.The particle size distribution of RMP is wider than that of cement,and the particles with smaller particle size can effectively fill the matrix gap.Therefore,when the substitution rate of RMP is large,it has little effect on the strength of the matrix.The three kinds of fiber-reinforced cementitious composites with recycled mortar powder(RMP-FRCC)show excellent strain hardening characteristics and multi-crack cracking ability.The ultimate strain reaches more than 8%,the crack distribution is uniform,and the average crack width under the limit strain state is below 100μm.The replacement of 25%RMP with cement can significantly increase the strain hardening characteristics of FRCC,but the larger replacement rate(50%)will reduce the mechanical properties and strain indexes.

关 键 词：再生砂浆粉 建筑垃圾 纤维增强水泥基复合材料 拉伸性能 裂缝分布 

分 类 号：TU525.9[建筑科学—建筑技术科学]