This paper presents a general procedure based on fracture mechanics models in order to analyze the level of cracking and structural safety in reinforced concrete elements at early ages, depending on the stripping time. Our procedure involves the development of a thermo-mechanical numerical model based on the finite element method that accounts for the change in the mechanical properties of concrete with time. Moreover, fracture mechanisms are analyzed by means of a material damage model, which is characterized via specific experimental results obtained for standard specimens and notched beams under three-point bending testing. The loading conditions are both thermal and mechanical, and are obtained from the hydration process for a given concrete dosage. The presented methodology allows for the determination of the optimal stripping time, whereas it helps assessing the analysis of the cracking and the stress states of the elements under consideration. A practical application, namely the analysis of a retaining wall, is used to validate our methodology, showing its suitability in engineering practice.

中文翻译：

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一种基于有限元的混凝土结构早期行为热力学分析方法

本文提出了一种基于断裂力学模型的一般程序，以分析早期钢筋混凝土构件的开裂水平和结构安全性，这取决于剥离时间。我们的程序涉及基于有限元方法的热机械数值模型的开发，该模型解释了混凝土机械性能随时间的变化。此外，通过材料损伤模型分析断裂机制，该模型通过标准试样和缺口梁在三点弯曲试验下获得的特定实验结果进行表征。加载条件是热的和机械的，并且是从给定混凝土剂量的水化过程中获得的。所提出的方法允许确定最佳剥离时间，而它有助于评估所考虑元素的开裂和应力状态的分析。一个实际应用，即挡土墙的分析，用于验证我们的方法，显示其在工程实践中的适用性。