Fundamental studies on the mechanisms of repair principle W-Cl and to ensure durability

保证钢筋混凝土结构的耐久性是一项技术要求很高的任务。保持真实的房地产投资组合的流动性和安全性对社会具有重要意义。含氯环境对钢筋混凝土的影响起着重要的作用，因为这些损伤的修复会造成相当大的经济损失。由于氯化物进入钢筋混凝土，钢筋可能失去其钝化性，导致点蚀。钢筋横截面的显著损失会导致承载能力和可用性受损。在传统的修复方法中，通常必须移除含氯化物的混凝土，然后重新成型。与传统的修复方法相比，如果W-Cl修复概念能够准确地应用，则氯离子污染结构的修复将更具成本效益。修复原则W-Cl包含在混凝土表面上涂覆涂层（例如，G.停车平台或地下停车场的底板），这防止了氯化物和水的进一步渗透，但它允许相反地干燥该结构。通过混凝土的干燥，腐蚀过程显着减速，使进一步的损害可以转移到一个非临界区域，甚至可以完全停止。边界条件的低风险的实际应用，其中腐蚀活动可以降低到一个临界速率下，还没有研究。为保证其在实践中的安全应用，必须进行基础研究。一点是根据环境湿度和氯化物含量确定混凝土的吸附等温线。进一步的要点是测试在表面保护涂层下发生的混凝土的干燥行为和部分水饱和混凝土中相应的氯离子再分布。此外，腐蚀速率必须确定取决于混凝土的含水量，以确定一个非临界含水量的腐蚀速率，这取决于氯化物container.The挑战，本研究项目包括在插入已知的和稳定的浓度的氯化物到混凝土的必要性和困难，能够正确地把握部分饱和混凝土中的氯化物重排。这些研究都伴随着电化学测定钢筋的腐蚀活性在含氯部分水饱和混凝土。所得到的结果被用作输入参数，随后的数值模拟的时间依赖性的腐蚀活动的实际相关的维护和维修工作的原则上的W-Cl。

It is a technically demanding task to ensure the durability of reinforced concrete structures. It is of high significance for the society to maintain the mobility and to secure the real estate portfolio. Effects of chloride-containing environments on reinforced concrete play an important role because the repair of these damages causes a considerable economic damage. Due to chloride ingress into reinforced concrete the reinforcement bars can lose their passivity leading to a pitting corrosion. Significant loss of cross section of the rebar can lead to impairment of the load bearing capacity and usability.Chloride-containing concrete usually has to be removed and subsequently re-profiled in conventional repair methods. The repair of chloride-contaminated structures would be much more cost-efficient compared to conventional repair methods if the repair concept W-Cl could be applied unerringly. The repair principle W-Cl contains the application of a coating on concrete surfaces (e. g. a parking deck or a base slab of an underground parking), which prevents the further penetration of chloride and water, but it permits the drying of the structure contrariwise. By the drying of the concrete the corrosion processes are significantly decelerated, so that the further damage can be shifted to an uncritical area or can even completely stopped.The boundary conditions for a low-risk practice application, where the corrosion activity can be reduced under a critical rate, are not studied yet. To ensure the safe application in practice, basic research must be carried out. One point is the determination of the sorption isotherms of the concrete depending on the ambient humidity and the chloride content. Further points are tests about the drying behavior of the concrete taking place under surface protection coatings and the corresponding redistribution of chloride in partially water-saturated concrete. Furthermore corrosion rates have to be determined depending on the moisture content of concrete in order to define an uncritical moisture content for the corrosion rate which depends on the chloride content.The challenge of this research project consists in the necessity to insert chlorides in known and steady concentration into the concrete and the difficulty to be able to grasp correctly the chloride rearrangement in part-saturated concretes. These studies are accompanied by electrochemical determination of the corrosion activity of reinforcing steel in chloride-containing partially water-saturated concrete. The obtained results are used as input parameters for the subsequent numerical simulation of the time dependent corrosion activity for practice-related maintenance and repair work on the principle of W-Cl.