基于分形理论的废弃纤维再生混凝土梁受弯性能研究  

Study on flexural performance of recycled concrete beams with waste fiber based on fractal theory

作　　者：周静海[1] 吴晓鑫 于杭琳 赵琦 张广祺 ZHOU Jinghai;WU Xiaoxin;YU Hanglin;ZHAO Qi;ZHANG Guangqi(School of Civil Engineering,Shenyang Jianzhu University,Shenyang 110168,Liaoning,China)

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168

出　　处：《建筑科学与工程学报》2023年第4期52-59,共8页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51678374);辽宁省教育厅青年基金项目(lnqn202003);辽宁省高等学校创新团队项目(LT201911);中央高校基本科研业务费专项资金项目(300102341511)。

摘　　要：为了定量分析不同再生骨料取代率、不同废弃纤维掺量的废弃纤维再生混凝土梁的受弯开裂及裂缝发展特征,基于分形理论研究了不同再生骨料取代率、废弃纤维体积掺量钢筋混凝土梁构件的弯曲开裂演化过程;运用盒计数法理论对废弃纤维再生混凝土梁表面裂缝分布特征进行了分析,进而研究了再生骨料取代率、废弃纤维掺量对试件受弯性能的影响规律。结果表明:废弃纤维再生混凝土梁表面裂缝分布的分形维数在0.9~1.25之间,荷载和跨中挠度的增大对分形维数的变化有较大影响;随着废弃纤维掺量的增大,分形维数呈先减小后增大的趋势,在极限状态下,随着再生骨料掺量增大,分形维数变大;分形维数可以描述裂缝的发展过程,FRC-0.12-50的分形维数最接近NC-0-0;分形维数越小,梁的受弯性能越好,梁表面裂缝分形维数可作为衡量梁受弯性能的指标;采用分形维数分析试件的受弯性能可作为梁受弯性能研究及评定的一种有效技术手段。In order to quantitatively analyze the flexural cracking and crack development characteristics of recycled concrete beams with waste fiber under different recycled aggregate replacement rates and waste fiber content,the evolution process of flexural cracking of reinforced concrete beams with different recycled aggregate replacement rates and waste fiber volume content was studied based on fractal theory.The box counting method was used to analyze the distribution characteristics of cracks on the surface of recycled concrete beams with waste fiber,and then the effects of the replacement rate of recycled aggregate and the amount of waste fiber on the flexural performance of the specimens were studied.The results show that the fractal dimension of crack distribution on the surface of recycled concrete beams with waste fiber is between 0.9 and 1.25,and the increase of load and midspan deflection has a significant impact on the change of fractal dimension.With the increase of waste fiber content,the fractal dimension tends to decrease first and then increase.In the ultimate state,the fractal dimension increases with the increase of recycled aggregate content.Fractal dimension can describe the development process of cracks,and the fractal dimension of FRC-0.12-50 is closest to NC-0-0.The smaller the fractal dimension,the better the flexural performance of the beam.The fractal dimension of the crack on the beam surface can be used as an indicator to measure the flexural performance of the beam.Using fractal dimension to analyze the flexural performance of specimens can be an effective technical means for studying and evaluating the flexural performance of beams.

关 键 词：废弃纤维再生混凝土 简支梁 受弯性能 分形维数 

分 类 号：TU528[建筑科学—建筑技术科学]