高性能混凝土的早期极限拉应变

混凝土的早期抗拉性能是评价和预测混凝土结构早期开裂不可或缺的重要参数,但并未受到国内研究同行的重视。高性能混凝土较普通混凝土更易于发生早期开裂,故对其抗拉性能加以研究意义重大。本文通过自行设计的实验装置对高性能混凝土早龄期极限拉应变进行了试验研究。结果发现,高性能混凝土硬化期间极限拉应变极高,并随龄期迅速递减,达到最小值后又缓慢回升并渐趋稳定。基于试验结果和CEB-FIP MC 90对高性能混凝土的早期极限拉应变进行了初步评价。

Tensiel Strain Capacity of High Performance Concrete at Early Ages

Early-age tensile properties of concrete are indispensable parameters to evaluate and predict early-age cracking,but have never received much attention.Compared to normal strength concrete,high performance concrete(HPC) has much higher risks of early-age cracking,therefore,it is more significant to study tensile properties of HPC at early ages.In this paper,tensile strain capacity(TSC) of hardening HPC are experimentally investigated with self-designed testing rig.The results show that TSC of hardening HPC was very high,which rapidly decreased with age and minimum value is reached somewhat later.Evaluation for early-age TSC based on CEB-FIP Model Code(MC 90) and experimental results is also carried out.