论文部分内容阅读
介绍了钢筋混凝土结构在氯离子渗透、碳化和冻融侵蚀作用下的耐久性和服役寿命预测模型。过去几年有关组织或国际学术委员会提出了大量的混凝土结构耐久性设计模型。为了在混凝土结构耐久性设计过程中,能够安全地使用此类模型,需要通过分析和比较长期暴露在不同气候条件下的混凝土劣化现场数据,对预测模型的可用性进行验证。在本文中,对混凝土抗氯离子渗透、碳化和冻融侵蚀的各种模型进行了简要阐述。通过暴露时间超过20年的露天场数据,以及约使用了30年的公路桥的现场数据,对包括简单ERFC模型、DuraCrete模型和ClinConc模型在内的3种氯离子渗透模型进行了评估。同时,使用暴露11年的露天场所的现场数据和7~13年的现有建筑的有限数据对一种预测混凝土碳化深度的物理化学模型进行了评价。针对冻融侵蚀的模型,讨论了临界饱和度测量和实际的饱和度测量中的一些问题。根据对结果的比较,可以发现在大多数情况下,简单ERFC模型在大多数情况下对氯离子渗透的预测值高于实际值,而DuraCrete模型的预测值偏低。另外,ClinConc模型对短期(1年)和长期(21年)暴露条件下的预测更合理,预测效果更好。与在挪威获得的暴露级别为XC3现场数据比较,发现Papadakis碳化模型可以较好地预测碳化深度;但是,与暴露级别为XC4级的现场数据比较发现,该模型低估了碳化深度。
The durability and service life prediction models of reinforced concrete structures under chloride ion infiltration, carbonization and freeze-thaw erosion are introduced. In the past few years, relevant organizations or international academic committees have proposed a large number of concrete structure durability design models. In order to be able to use such models safely in the design of durability of concrete structures, the availability of prediction models needs to be verified by analyzing and comparing concrete degradation field data exposed to long-term exposure to different climatic conditions. In this paper, a brief account of various models of concrete resistance to chloride ion penetration, carbonation and freeze-thaw erosion is presented. Three models of chloride ion permeation, including the simple ERFC model, the DuraCrete model, and the ClinConc model, were evaluated by using open field data that has been exposed for more than 20 years, as well as field data on road bridges that have been used for about 30 years. At the same time, a physico-chemical model for predicting the carbonation depth of concrete was evaluated using on-site data from open-air sites exposed for 11 years and limited data from existing buildings aged from 7 to 13 years. For the model of freeze-thaw erosion, some problems in the measurement of critical saturation and actual saturation are discussed. Based on the comparison of the results, it can be found that in most cases, the predictions of chloride ion infiltration in simple ERFC model are higher than the actual value in most cases, while the predictions of DuraCrete model are low. In addition, the prediction of the ClinConc model is more reasonable and predictable under short-term (1 year) and long-term (21 years) exposure conditions. Comparisons with the XC3 field data obtained in Norway revealed that the Papadakis carbonation model is a good predictor of carbonation depth; however, the model underestimates depth of carbonation compared with field data at exposure level XC4.