再生混凝土三轴受压力学性能试验研究

为了研究再生混凝土在三轴应力状态下的力学性能,以再生骨料取代率和围压值为变化参数,设计了36个圆柱体试件,采用位移控制的加载方式进行常规三轴试验。通过试验观察了试件的破坏形态,获取试件受力破坏全过程应力-应变曲线以及峰值应力、峰值应变等特征参数,分析了再生骨料取代率和围压值对再生混凝土三轴受压力学性能的影响,提出了侧向围压值与初始弹性模量、竖向峰值应力、峰值应变之间的关系公式。研究结果表明：取代率对三轴受力再生混凝土的峰值应力和峰值应变影响不大,与天然混凝土相比,其变化分别在5%和2%的范围内波动,而取代率对再生混凝土的初始弹性模量有较大的影响,与天然混凝土相比,三轴受力再生混凝土的弹性模量提高了20%左右;侧向围压值对三轴受力再生混凝土的各项性能指标影响显著,增大围压值能有效提高再生混凝土的弹性模量、承载能力和变形性能。研究结果为再生混凝土的进一步科学研究和推广应用提供参考。

EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES OF RECYCLED CONCRETE IN TRI-AXIAL COMPRESSION

In order to study the mechanical behaviors of recycled coarse aggregate concrete under tri-axial compression, 36 cylinder specimens were designed for conventional tri-axial tests, and two parameters were considered in the tests, namely the replacement ratio of recycled coarse aggregate and lateral confinement. The failure patterns of the specimens were observed, and the stress-strain curve and characteristic parameters (such as peak stress and peak strain) were obtained by the test. Based on the test data, the influence of the replacement ratio and lateral confinement on tri-axial compression mechanical performance was analyzed, and some formulae for initial elastic modulus, vertical peak stress and peak strain in different confinement value were put forward. The experimental study shows that the replacement ratio of recycled aggregate concrete has little influence on the peak stress and peak strain in tri-axial compression, but has great influence on initial elastic modulus. Compared with natural concrete, peak stress variation range is about 5%, peak strain variation range is about 2%, and the elastic modulus increased about 20%. Lateral confinement value significantly impacts the technical specifications of the recycled concrete under tri-axial compression, and increasing lateral confinement value can effectively improve the elastic modulus, bearing capacity, and deformation performance of recycled concrete.