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设计制作了5根不同粗骨料替换率的无粘结预应力再生粗骨料混凝土试验梁,并采用两点加载对其进行正截面受弯性能试验,研究了无粘结预应力再生粗骨料混凝土的梁破坏形态、承载力、裂缝宽度及跨中挠度等力学性能。基于试验数据建立了与《混凝土结构设计规范》(GB 50010—2010)相协调的无粘结预应力再生粗骨料混凝土梁预应力钢筋应力增量计算公式,提出了无粘结预应力再生粗骨料混凝土梁的最大裂缝宽度及刚度的设计建议。结果表明:再生粗骨料替换率对无粘结预应力再生粗骨料混凝土梁的破坏形态、裂缝宽度、跨中挠度影响不大;达到承载力极限状态时无粘结预应力再生粗骨料混凝土梁的无粘结预应力钢筋应力增量比无粘结预应力混凝土梁的无粘结预应力钢筋应力增量大,但再生粗骨料替换率对应力增量的影响不显著。
Five non-bonded prestressed recycled coarse aggregate concrete test beams with different replacement rates of coarse aggregate were designed and fabricated. The two-point loading was used to test the flexural behavior of the specimens. The effects of unbonded prestressed regenerated coarse bone Concrete beam failure morphology, bearing capacity, crack width and mid-span deflection and other mechanical properties. Based on the experimental data, the formula of stress increment of unbonded prestressed recycled coarse aggregate concrete beam in coordination with “Code for Design of Concrete Structure” (GB 50010-2010) was established, and the unbonded prestressed regenerated coarse Design Proposals for Maximum Crack Width and Stiffness of Aggregate Concrete Beams. The results show that the replacement rate of recycled coarse aggregate has little effect on the failure mode, crack width and mid-span deflection of unbonded prestressed recycled coarse aggregate concrete beams. When the load-bearing capacity reaches the ultimate state, the unbound pre-stressed coarse aggregate The stress increment of unbonded prestressed steel bar of concrete beam is larger than that of unbonded prestressed steel bar of unbonded prestressed concrete beam, but the effect of replacement rate of recycled coarse aggregate on stress increment is insignificant.