External Sulfate Attack to Reinforced Concrete Under Drying-Wetting Cycles and Loading Condition: Numerical Simulation and Experimental Validation by Ultrasonic Array Method
External Sulfate Attack to Reinforced Concrete Under Drying-Wetting Cycles and Loading Condition: Numerical Simulation and Experimental Validation by Ultrasonic Array Method
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DOI：
10.1016/j.conbuildmat.2017.02.064
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发表时间：
2017-05
影响因子：
7.4
通讯作者：
Jinrui Zhang;Ming Sun;D. Hou;Zongjin Li
中科院分区：
文献类型：
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作者：
Jinrui Zhang;Ming Sun;D. Hou;Zongjin Li
本文建立了一个新的数学模型，该模型考虑了孔隙溶液蒸发的滞后效应和水分扩散系数与孔隙溶液饱和度之间的非线性关系，用于描述干湿循环下硫酸盐对钢筋混凝土的侵蚀。通过钢筋混凝土梁的四点弯曲试验，研究了硫酸盐侵蚀和外荷载条件的耦合效应，并与模型预测值进行了比较。在试验中，采用超声波阵列法检测混凝土在硫酸盐侵蚀和荷载作用下损伤引起的弹性模量场的变化。外荷载在混凝土基体内部产生拉应变，加速了硫酸盐侵蚀下混凝土的劣化过程。硫酸盐侵蚀下混凝土模量随荷载的变化呈现两个明显阶段：（1）钙矾石结晶增强阶段和（2）过度膨胀弱化阶段。实验结果验证了本文提出的硫酸盐侵蚀与荷载耦合作用下的扩散模型的合理性和有效性。
In this paper, an innovative mathematic model dealing with the hysteresis effect of evaporation of pore solution and the nonlinear relationship between diffusivity of moisture and saturation degree of pores solution is established to describe the sulfate attack to reinforced concrete with drying-wetting cycles. The coupling effects of sulfate attack and external loading condition are investigated using a four-point-bending experiment on a reinforced concrete beam and compared with the model predictions. In the experiments, ultrasonic array method is employed to detect the change of the field of modulus of elasticity due to the damage in concrete under sulfate attack coupled with loading condition. The external loading, resulting in tensile strain inside concrete matrix, accelerates the degradation process of concrete subjected to sulfate attack. The modulus variation of concrete under sulfate attack with loading exhibits two apparent stages: (1) the enhancing stage of ettringite crystallization and (2) weakening stage due to overexpansion. The experimental results verified the rationality and validity of the diffusion model proposed in this study, considering the coupling effects of external sulfate attack and loading condition.