再生混凝土的单轴压缩动态力学性能

Dynamic Mechanical Properties of Recycled Concrete under Uniaxial Compression

关键词:  再生混凝土  应变率效应  单轴压缩  应力-应变关系  细观损伤机制

Key words:  recycled concrete  strain rate effect  uniaxial compression  stress-strain relation  meso-damage mechanism

摘要:

利用再生粗骨料取代天然粗骨料制备再生混凝土，开展了单轴受压动态力学性能试验，研究了应变速率、再生骨料取代率对再生混凝土应力-应变曲线特征、弹性模量、抗压强度和峰值应变的影响.利用统计损伤模型分析了再生混凝土的细观损伤演化规律.结果表明：不同应变速率下再生混凝土的单轴压缩应力-应变全曲线具有相似性，随着应变速率的提高，其抗压强度、弹性模量呈增大趋势，峰值应变则逐渐减小；当取代率为100%时，再生混凝土表现出更显著的应变速率敏感特性；随着应变速率的提高，表征细观损伤非均质演化过程的特征参数呈现出明显规律性的变化，与微结构应变率效应机理、宏观非线性本构行为之间表现出良好的一致性.

Abstract:

The natural coarse aggregate was replaced with recycled coarse aggregate to prepare recycled concrete. The dynamic mechanical properties of the recycled concrete under uniaxial compression were tested. The effects of strain rate and replacement rate of recycled aggregate on the stress-strain curve characteristics， elastic modulus， compressive strength and peak strain were studied. The mesoscopic damage evolution of recycled concrete was analyzed by the statistical damage model. The results show that the whole stress-strain curves of recycled concrete under uniaxial compression have similar characteristics under different strain rates. With the increase of strain rate， the compressive strength and elastic modulus tend to increase， while the peak strain decreases gradually. When the substitution rate is 100%， the recycled concrete shows more obvious strain rate sensitivity. With the increase of strain rate， the characteristic parameters that characterize the heterogeneous evolution process of mesoscopic damage change with obvious regularity， which is in good agreement with the strain rate effect mechanism of microstructure and the macroscopic nonlinear constitutive behavior.