盐腐蚀后混凝土的动态本构模型

摘要

为探究混凝土受盐腐蚀后的动态力学响应,配置了粉煤灰质量分数为15％的普通硅酸盐水泥混凝土,将其置于质量分数均为15％的NaCl和Na2SO4溶液中浸泡腐蚀60d后,利用φ100 mm分离式霍普金森压杆实验装置,测试其受腐蚀后的动态力学性能,并结合宏观唯象损伤统计理论和Weibull分布思想,建立了混凝土受盐腐蚀后的动态统计损伤本构模型.结果表明:受盐腐蚀后,混凝土试件的动态抗压强度均有不同程度的下降,且NaCl溶液腐蚀试件的降幅大于Na2SO4溶液腐蚀试件;模型曲线与实验曲线的拟合度较高,能够较准确地描述混凝土在冲击荷载作用下的动态力学响应规律.%To explore the dynamic mechanical behaviors of the concrete corroded by salt solution,we fabricated concrete specimens of ordinary Portland cement with fly ash of 15％ mass fraction and,having them immersed for 60 d in NaCl and Na2SO4 solutions with a 15％ mass fraction,studied their dynamic mechanical properties using a φ100 mm split Hopkinson pressure bar apparatus.Then,based on the macro phase-only statistical damage theory and the Weibull distribution theory,we built a dynamic statistical damage constitutive model for the specimen's mechanical behaviors.The results indicate that the dynamic compressive strength of the corroded specimens experiences a significant decrease,and the declines of the specimens corroded by NaC1 are bigger than those corroded by Na2SO4.Based on the closely fitted curves of the model and the experiment,this established model can accurately estimate the dynamic mechanical behaviors of concrete under impact loading.