混凝土硫酸盐侵蚀离散元模拟初探

Preliminary study on sulfate attack in concrete by the Discrete Element Method

将普通混凝土视为水泥胶结骨料的聚集体,受硫酸盐侵蚀的过程简化为粒间胶结物的减少,将此侵蚀因素引入已有的无厚度有抗转动的颗粒胶结接触模型中并利用DEM模拟混凝土受硫酸盐的侵蚀,并与室内试验作对比分析,结果表明:该模型能够反映混凝土受硫酸盐侵蚀的作用:单轴抗压强度随反应时间的增加而减小,抗压抗蚀系数也随时间减小;试样破坏形态在初期为可见的碎块状,而在长时间的侵蚀后,破坏后的碎块较小,从表面看不到试样中的大裂隙;试样的胶结破坏以拉剪扭破坏为主。

The sulfate attack in concrete can be treated as a process of bonding material loss with the reduction of bond's width. The factor of sulfate is implanted into the existing non-height cement bonding mod-el to simulate and analyze the sulfate effect on the concrete by the discrete element method(DEM). Com-parison is made with indoor sulfate experiments. The results show that the mechanical properties and mainfeatures can be reflected by this model. The uniaxial compressive strength and the coefficient of anti-erosion(K) continually reduce with erosion time. What's more,the failure mode is chunky at the early stageof erosion. While it behaves crushed after a long-term erosion. Tensile shear and torsion failure is the major failure of bond.