混凝土碳化是导致钢筋混凝土(RC)结构性能退化的主要原因之一,这种性能退化降低了RC结构的耐久性、适用性和安全性。因此,混凝土碳化深度的预测模型研究可为RC结构的耐久性评价和使用寿命预测提供参考,具有重要意义。首先,论文依据国内外公开发表的公开参考文献,收集整理了273组国内混凝土自然碳化深度实测数据,并绘制了碳化深度直方图,经Kolmogorov-Smirnov拟合优度检验,发现碳化深度实测数据服从Gamma概率分布；随后,基于中国国家标准GB-T51355-2019模型和国际标准CEB-FIP-2010模型,结合RC结构混凝土碳化的自然环境,梳理分析了影响混凝土碳化过程的主要因素,发现混凝土时效抗压强度、环境相对湿度、温度、养护机制、CO2浓度和有无挡雨情形等为主要影响因素；其次,基于RC结构混凝土自然碳化过程是一个随机、单调和递增过程,使用Gamma随机过程模型对其进行表征,并在此基础上,以上述主要影响因素作为预解释变量,构建了一个新的混凝土自然碳化深度预测Gamma广义线性回归模型。最后,采用本文模型预测RC结构混凝土自然碳化深度,与实测数据、国家标准模型、国际标准模型预测结果进行对比分析。结果表明,本文模型具有较好的预测精度,优于现有国家和国际标准模型,可以作为一个有潜在应用价值的代理模型进行应用。

Concrete carbonization is one of the major reasons for the degradation of reinforced concrete (RC) structures, which reduces their durability, serviceability and safety. Therefore, the reasonable prediction model of concrete carbonation depth can provide a reference for durability evaluation and service life prediction of RC structures and be of great significance. Firstly, 273 sets of measurements of China natural carbonation depth of concrete from publications in China and foreign journals were collected and depicted with the histogram. According to the Kolmogorov-Smirnov goodness of fit test, it was found that the measurements of carbonization depth follows Gamma probability distribution. Subsequently, in terms of the Chinese national standard GB-T51355-2019 model and the international standard CEB-FIP-2010 fib-model along with the natural environment of RC structure concrete carbonization, the main factors affecting the process of concrete carbonization were analyzed, concluding that concrete aging compressive strength, relative humidity, temperature, curing mechanism, CO₂ concentration, shelter and rain are the main influencing factors. Secondly, due to the fact that the natural carbonization process of RC concrete is a random, monotonic and increasing one, the Gamma stochastic process model was thus used to characterize it. Using the model and the above main influencing factors as explanatory variables, a new Gamma generalized linear regression model for the natural carbonization depth prediction of concrete was established. Finally, the natural carbonation depth of real RC structure concrete was calculated by the proposed model, and compared with the measured data as well as the predictions by the Chinese standard model and the international fib-model. It was shown that the proposed model has better accuracy in predicting carbonation depth of RC structural concrete than the existing national and international standard models do, and can be used as a potential surrogate model.

TU37

国家自然科学(52278180) 和(51878275)