Linear and Non-Linear Cyclic-Creep of Concrete with defined Moisture Contents

钢筋混凝土桥梁的变形测量表明，实测的实际变形明显大于设计时计算的变形。一个重要的原因是现有的蠕变模型既没有考虑机械应力的循环性质，也没有考虑混凝土内部不同的含水率。因此，卡尔斯鲁厄理工学院、汉诺威莱布尼茨大学和Bergische Universität Wuppertal联合项目的目标是开发一个考虑荷载循环性质和混凝土含水率的长期变形的广义模型。涵盖了线性和非线性蠕变变形的范围。这些广泛的实验是推广现有流变蠕变模型的基础。为了改进模型和更好地理解潜在的机制，不同的变形将被分为以下几个部分：弹性变形，延迟弹性变形以及不可逆蠕变。不可逆变形将进一步分裂为蠕变，无论有无微裂纹等结构变化。目的是提供一个增强的和广义的模型，用于预测混凝土的长期变形，考虑到荷载的循环性质以及混凝土内的湿度条件。

Deformation measurements of reinforced concrete bridges have shown that the measured actual deformations significantly exceed the deformations calculated during design. One important reason is that the existing creep models neither take into account the cyclic nature of mechanical stresses nor the different moisture contents inside the concrete. Therefore, the aim of the joint-project at the Karlsruhe Institute of Technology, the Leibniz University in Hannover and the Bergische Universität Wuppertal is to develop a generalized model for the long-term deformation that takes the cyclic nature of the loading and the moisture content of concrete into account. The ranges of linear and non-linear creep deformations are covered. These extensive experiments are the basis for generalization of existing rheological creep models. For an improvement of the model and for a better understanding of the underlying mechanisms differentdeformations will be split up into the following parts: elastic deformations, delayed-elastic deformations as well as irreversible creep. The irreversible deformations will be further split up into creep with and without changes in structure such as micro-cracking. The aim is to provide an enhanced and generalized model for the prediction of the long-term deformations of concrete that takes into account the cyclic nature of the loading as well as the moistureconditions within the concrete.