不同作用下混凝土加速钙溶蚀的数值模拟

Numerical simulation of accelerated calcium dissolution of concrete under different effects

服役于酸性环境中的混凝土钙溶蚀将会加速,影响结构的耐久性,危害结构安全。为准确模拟酸性环境中固相钙的溶解和钙离子的迁移,本文考虑了H^(+)的影响,提出了变化加速扩散系数的概念,并依据酸性腐蚀溶液中H+浓度和孔隙液中钙离子浓度,建立了变化加速扩散系数。同时改变边界条件,以模拟不同作用对于钙溶蚀的影响。依据建立的钙溶蚀模型,模拟了混凝土在pH=4的酸性条件中和不同作用下的加速钙溶蚀。模拟的耗酸量与实测耗酸量相吻合,腐蚀1000h后,模拟误差基本小于20%。计算得到的孔隙液中钙离子分布与实际情况相一致。

Concrete calcium leaching in acidic environments will be accelerated,affecting the durability of structures and jeopardizing their safety.To accurately simulate the dissolution of solid-phase calcium and the migration of calcium ions in acidic environments,this paper considers the influencing factor of H^(+)and proposes the concept of a variable accelerating diffusion coefficient.Based on the concentrations of H+in the acidic corrosion solution and calcium ions in the pore solution,a variable accelerating diffusion coefficient is established.Additionally,changes in boundary conditions are applied to simulate the effects of different actions on calcium leaching.Using the established calcium leaching model,accelerated calcium leaching of concrete under pH 4 acidic conditions and various actions is simulated.The simulated acid consumption is in good agreement with the measured acid consumption,with the simulation error generally below 20%after 1000 hours of corrosion.The distribution of calcium ions in the pore solution calculated through the simulation is consistent with the actual situation.