三轴受压状态下再生混凝土强度与变形性能试验研究

为了研究三轴受力状态下再生混凝土强度随再生粗骨料取代率的变化规律,通过RMT-150C对三种强度等级(C20、C30、C40)五种再生粗骨料取代率(0、30%、50%、70%、100%)的混凝土φ50 mm×100 mm圆柱体进行三轴抗压强度压缩试验,分析了不同再生粗骨料取代率对再生混凝土三轴强度、峰值应变以及应力-应变全曲线的影响.试验结果表明:再生混凝土试件与普通混凝土试件的破坏形态相似,但再生粗骨料与普通粗骨料最后的破坏形态差异较大;C20混凝土随再生粗骨料取代率的增大,其峰值应力先增大后减小,且取代率为50%时再生混凝土峰值应力最大,约高于普通混凝土的10%;C30混凝土的平均峰值应力随再生粗骨料取代率的增加,其变化规律不明显,但再生混凝土的平均峰值应力均低于普通混凝土的;C40混凝土平均峰值应力随再生粗骨料取代率的增加而降低,当取代率为100%时,再生混凝土平均峰值应力约低于普通混凝土的15%.在三轴应力状态下,再生混凝土受压应力-应变全曲线的形状与普通混凝土的相似.

Recycled Concrete Strength and Deformation Performance Tests in Triaxial Compressive State

In order to investigate the variation of recycled concrete strength in the triaxial stress state with the different replacement ratios of recycled coarse aggregate, the experiments of Ф 50 mm × 100 mm solid cylinders were conducted by RMT-150C, and the cylinders were made into three different strengths （C20, C30, C40）and five different replacement ratios （0, 30%, 50%, 70%, 100%） of recycled coarse aggregate. The effects of different recycled coarse aggregate replacement ratios on the triaxial strength, peak strain and stress-strain curve of recycled concrete were analyzed. Test results show that the failure mode of recycled concrete are similar to that of the ordinary concrete, whereas the final failure mode of recycled coarse aggregate is quite different from that of the natural aggregate. With the increase of recycled coarse aggregate replace- ment ratios, the peak stress of C20 concrete firstly increases and then decreases ; when the recycled coarse aggregate re- placement ratio is 50%, the peak stress of C20 recycled concrete is about 10% higher than natural concrete; the regularity of peak stress of C30 concrete is not obvious with the increase of the recycled coarse aggregate replacement ratios, but the peak stress of recycled concrete was lower than natural concrete peak stress; the average peak stress of C40 concrete is reduced when the ratio of recycled coarse aggregate replacement is increased; when the ratio of recycled coarse aggregate replace- ment is 100%, the peak stress of recycled concrete is about 15% lower than natural concrete peak stress. In the triaxial stress state, the recycled concrete stress-strain curve shape is similar to natural concrete stress-strain curve shape.