水玻璃强化再生混凝土单轴受压本构关系

The uniaxial compression constitutive relation of recycled concrete reinforced with sodium silicate

再生混凝土本构关系的研究是进行再生混凝土结构抗震设计的关键.采用水玻璃浸泡强化再生粗骨料(RCA),制备不同再生粗骨料取代率的再生混凝土,进行立方体抗压强度及单轴受压试验,与天然骨料混凝土(NAC)对比,探讨了水玻璃强化方法和再生粗骨料取代率对混凝土力学性能的影响.结果表明:水玻璃强化方法降低了再生粗骨料的吸水率和压碎指标;强化后的再生粗骨料混凝土应力应变曲线具有更高的弹性模量和峰值应力,但仍低于天然骨料混凝土;水玻璃强化再生粗骨料混凝土的峰值应变呈现先增加后减少趋势;再生混凝土的泊松比保持稳定,应力应变曲线与天然混凝土相似.通过回归分析,提出不同取代率下水玻璃强化再生粗骨料混凝土受压本构方程,方程与试验结果吻合较好.

The research on constitutive relation of recycled concrete is the basis to investigate seismic design of recycled concrete structure.In this study,sodium silicate was used to enhance the quality of recycled coarse aggregate(RCA).Recycled concrete samples with different replacement rates of RCA were prepared.Cubic compressive strength and uniaxial compression tests were carried out to investigate the influence of the chemical treatment method and the replacement rate of RCA on their mechanical properties compared with natural aggregate concrete(NAC).The results show that sodium silicate treatment method reduces the water absorption and crushing index of RCA.The stress-strain curve of treated-RCA concrete presents higher elastic modulus and peak stress than that of RAC but is still lower than that of NAC.The peak strain of recycled coarse aggregate concrete strengthened by sodium silicate first increases and then decreases.Poisson's ratio of recycled concrete remains stable and the stress-strain curve is similar to that of natural concrete.Through regression analysis,the constitutive equation of recycled coarse aggregate concrete reinforced with sodium silicate with different replacement rate is proposed.The stress-strain equation for RCA concrete is in good agreement with the experimental results.