高强混凝土收缩尺寸效应及预测模式修正方法

Size Effects and Modified Method of Predietion Model on High Strength Conerete Shrinkage

为了将实验室标准条件下测量的数据更好地用于实际桥梁建设和维护中,本文研究了环境相对湿度和试件尺寸对混凝土收缩的影响。研究结果表明,试件的尺寸不仅影响干燥收缩的进程,对干燥收缩终值也有很大的影响,尺寸越小,混凝土干燥收缩越大,混凝土的尺寸效应随着湿度降低而增加。结合CEB-FIP1978,根据试验结果修正了CEB-FIP1990收缩模式,修正后的模型计算结果与试验值的比较表明,按照本文的处理方法可以提高模型预测精度,为将实验室预测结果较好地推广到实际结构收缩的预测中提供了一种修正方法。

In order to apply the data from laboratory to the structure shrinkage prediction in field, the effects of environment relativ6 humidity and specimen size on concrete shrinkage are studied. The results show that the specimen size not only affects the progress of shrinkage but also the final shrinkage strain. Drying shrinkage increases with smaller specimen size. The size effect is more prominently when the environment relative humidity is lower. Combining with CEBFIP1978, the CEB-FIP1990 model is improved based on the experiment result, and the calculation value is compared with experiment value. The prediction accuracy is improved remarkably by the improved model, which provides a modified method for the laboratory prediction into practical structure shrinkage prediction.