考虑骨料表面强化的再生混凝土内氯离子传输细观数值模拟

采用纳米强化再生骨料表面的措施来改善再生骨料性能,建立多相再生混凝土细观数值模型,进行氯离子在再生混凝土内部传输的模拟和试验验证,并预测了氯盐环境下再生骨料表面强化混凝土耐久性寿命。结果表明:数值模拟得到的氯离子在再生混凝土内的分布与试验结果吻合较好;同一深度处,越靠近骨料表面,氯离子浓度越大,其中未强化再生骨料表面的氯离子浓度要大于强化再生骨料表面的氯离子浓度;增加保护层厚度可以有效提高纳米强化再生混凝土在氯盐环境下的耐久性寿命;随纳米包裹层氯离子扩散系数的减小,再生混凝土的耐久性寿命有所增加。

Mesoscopic Numerical Simulation of Chloride Ion Transportation in Recycled Aggregate Concrete with Surface Strengthened Aggregate

The performance of recycled aggregate(RA)was improved by pre-soaking the RA in nano-SiO;solution to enhance its weak surface.A mesoscopic model of multi-phase for recycled aggregate concrete(RAC)was established to simulate the chloride ion transportation in concrete.Experiments of RAC immersing in chloride ion solution were carried out to verify the simulation results,and service life of RAC exposed in chloride ion environment was predicted.The results indicate that the mesoscopic numerical simulation results are in good agreement with the experimental results.At the same depth,the closer to the aggregate surface,the greater the chloride ion concentration,and the concentration of chloride ion on the surface of un-strengthened RA is higher than that on the surface of strengthened RA.Increasing the thickness of protective layer effectively improves the durability life of the nano-strengthening RAC in chloride environment.The durability life of RAC increases a little with the decrease of chloride ion diffusion coefficient of nano-coating layer.