再生骨料混凝土弯曲疲劳性能研究  

Study on flexural fatigue performance of recycled aggregate concrete

作　　者：游帆 念梦飞[1] 郑建岚 罗素蓉[1] YOU Fan;NIAN Mengfei;ZHENG Jianlan;LUO Surong(College of Civil Engineering,Fuzhou University,Fuzhou 350108,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,福建福州350108 [2]福建江夏学院工程学院,福建福州350108

出　　处：《建筑结构学报》2022年第4期134-141,共8页Journal of Building Structures

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),福建江夏学院科研人才培育项目(JXZ2021012)。

摘　　要：为研究再生骨料混凝土的疲劳性能以及硅灰对其疲劳性能的影响,开展了天然骨料混凝土(NAC)、再生骨料混凝土(RAC)和硅灰再生骨料混凝土(RAC-SF)在3种应力水平下的弯曲疲劳试验,进行了弯曲疲劳寿命的Weibull分布检验,建立了弯曲疲劳寿命概率方程,并利用纳米压痕技术分析了3种混凝土界面过渡区的差异及其对疲劳性能的影响。结果表明:RAC的弯曲疲劳寿命服从两参数Weibull分布,双对数疲劳方程可根据Weibull参数拟合得到;与NAC相比,RAC的多重界面过渡区厚度大、压痕模量低,更易出现裂缝的衍生与开展,使得在相同应力水平下,RAC的弯曲疲劳寿命比NAC低;而硅灰的掺入减小了RAC多重界面过渡区的厚度,提高了多重界面过渡区及新浆体的压痕模量,增强了RAC抑制疲劳损伤的能力,改善了RAC的抗弯曲疲劳性能,延长了使用寿命.To investigate the fatigue performance of recycled aggregate concrete and the effect of silica fume,flexural fatigue tests of natural aggregate concrete(NAC),recycled aggregate concrete(RAC)and silica fume recycled aggregate concrete(RAC-SF)were carried out at three stress levels.The Weibull distribution and the probability equation of flexural fatigue life were established and analysed.Furthermore,the relationship between interface transition zone(ITZ)and its effects on flexural fatigue performance were studied by using nano-indentation.The results show that the flexural fatigue life of RAC follows two-parameters Weibull distribution and the double-logarithmic fatigue equation could be fitted by Weibull parameters.Compared with NAC,RAC has larger thickness and smaller indentation modulus of the multiple ITZs,which facilitates the derivation and development of cracks,accounting for the lower flexural fatigue life of RAC than that of NAC at the same stress level.The addition of silica fume to RAC results in the reduction of thickness of multi ITZs,and the increasing of indentation modulus of multi ITZs and new mortar.Moreover,the resistance to fatigue damage is enhanced and the flexural fatigue performance of RAC is improved,which consequently prolongs the service life of RAC.

关 键 词：再生骨料混凝土 硅灰 弯曲疲劳寿命 WEIBULL分布 纳米压痕 界面过渡区 

分 类 号：TU528[建筑科学—建筑技术科学] TU317.1