纳米改性再生骨料混凝土单轴受压疲劳性能  

FATIGUE BEHAVIOR OF NANO-MODIFIED RECYCLED AGGREGATE CONCRETE UNDER UNIAXIAL COMPRESSION

作　　者：罗素蓉[1] 承少坤 肖建庄[3] 游帆 LUO Su-rong;CHENG Shao-kun;XIAO Jian-zhuang;YOU Fan(College of Civil Engineering,Fuzhou University,Fuzhou 350116,China;Fujian Provincial Institute of Architectural Design and Research Co.,Ltd,Fuzhou 350001,China;College of Civil Engineering,Tongji University,Shanghai 200092,China;College of Engineering,Fujian Jiangxia University,Fuzhou 350108,China)

机构地区：[1]福州大学土木工程学院,福州350116 [2]福建省建筑设计研究院有限公司,福州350001 [3]同济大学土木工程学院,上海200092 [4]福建江夏学院工程学院,福州350108

出　　处：《工程力学》2021年第10期134-144,共11页Engineering Mechanics

基　　金：国家自然科学基金项目(52078139);国家自然科学基金海峡联合基金重点支持项目(U1605242)。

摘　　要：采用纳米二氧化硅对再生骨料混凝土(RAC)进行改性,开展了不同再生骨料取代率及纳米改性后的再生骨料混凝土单轴受压疲劳试验,研究其疲劳寿命、疲劳方程、疲劳变形规律及疲劳剩余强度,并利用纳米压痕试验从细观层面上分析探讨了纳米二氧化硅对再生骨料混凝土多重界面过渡区的影响。结果表明:再生骨料混凝土疲劳寿命均较好地服从两参数威布尔概率分布。50%保证率、0.75应力水平下,再生骨料混凝土的疲劳寿命比普通混凝土降低了25.8%,掺入纳米二氧化硅可显著提高再生骨料混凝土的疲劳寿命。对比应变演化曲线和剩余强度模型,纳米二氧化硅改性后的再生骨料混凝土,剩余强度衰减非线性规律明显。纳米二氧化硅的掺入提高了再生骨料混凝土多重界面过渡区的压痕模量,改善了再生骨料混凝土的疲劳性能。Recycled aggregate concrete(RAC)is modified by nano-silica to study the fatigue behavior due to uniaxial compressive repeated loading.Considering the recycled aggregate replacement rate as the main parameter,the fatigue life,fatigue equation,fatigue deformation law and residual stress of RAC are recorded and analyzed.Microscopically,the influence of nano-silica on multiple interface transition zones of RAC is discussed based on nanoindentation.The results show that the fatigue life of each group well obeys the two-parameter Weibull probability distribution.Under 50%guarantee rate and 0.75 stress level,the fatigue life of RAC with 100%recycled coarse aggregates is 25.8%lower than that of ordinary concrete.The incorporation of nano-silica improves the fatigue life of RAC significantly.Compared with other test group through the strain evolution curve and the residual stress model,the residual strength attenuation nonlinearity is obvious for RAC incorporating nano-silica.Nano-silica improves the indentation modulus of the multiple interface transition zones,which is the reason for the improvement of the fatigue behavior of RAC.

关 键 词：再生骨料混凝土 纳米二氧化硅 单轴受压疲劳 疲劳寿命 纳米压痕 

分 类 号：TU528.0[建筑科学—建筑技术科学]