Numerical modelling for predicting corrosion initiation life of reinforced concrete square piles under reverse-seepage pressure

基于反渗防腐技术的混凝土方桩耐久性寿命预测数值模型

Square piles of reinforced concrete(RC)in marine environments are susceptible to chloride-inducedcorrosion.A novel reverse-seepage technique(RST)is applied to square piles to block the intrusion of chlorides.Thisresearch introduces a computational model designed to predict the lifespan of corrosion initiation in reinforced concretesquare piles when applied reverse-seepage pressure.The model considers the impacts of chloride binding and the tripletime-dependence property among the permeability,the corrected surface chloride concentration,and the diffusioncoefficient.The proposed numerical model is solved using the alternating direction implicit(ADI)approach,and itsaccuracy and reliability are evaluated by contrasting the computational outcomes with the analytical solution andexperimental results.Furthermore,the primary factors contributing to the corrosion of reinforced concrete square pilesare analyzed.The results indicate that applying RST can decrease the chloride penetration depth and prolong the lifespanof corrosion initiation in square piles.The water-cement ratio and reverse seepage pressure are the most influentialfactors.A water pressure of 0.4 MPa can double the life of concrete,and the durable life of concrete with a water-cementratio of 0.3 can reach 100 years.

海洋环境中的钢筋混凝土方桩容易受到氯化物的腐蚀。新型反渗防腐技术应用于方桩内部阻止氯化物的侵入。本研究提出一种数值模型来预测基于反渗防腐技术下钢筋混凝土方桩的耐久性寿命,模型考虑了氯离子结合以及渗透率、表面氯离子浓度和扩散系数之间的三重时变特性,利用交替隐式差分进行求解,将求解过程与解析解和实验结果进行对比来验证模型准确性和可靠性。此外,分析了影响混凝土方桩的主要因素。结果表明,反渗防腐技术可以减少氯化物的渗透深度,延长方桩耐久性寿命,水灰比和反向水压是影响最大的因素,0.4 MPa的水压可以让混凝土的耐久性寿命延长一倍,水灰比为0.3的混凝土耐久性寿命可达100年。