再生粗骨料混凝土梁抗剪性能

Experimental Study on Shear Behavior of Recycled Coarse Aggregate Concrete Beams

目的研究再生粗骨料混凝土梁斜截面的受力变形能力与普通混凝土梁的差异.方法采用人工破碎的方式把废弃混凝土破碎后,参照普通混凝土配合比设计方法,对5组截面尺寸及配筋率相同,再生粗骨料取代率分别为0、10%、20%、30%、40%的混凝土梁进行抗剪试验.结果再生混凝土梁与普通混凝土梁的变形和斜裂缝开展情况基本相似,同样具有弹性、开裂、屈服和极限4个阶段,但抗剪极限承载能力存在差异,4种掺入量下再生混凝土梁的抗剪承载力比普通混凝土梁分别下降了1.3%、2.7%、4.8%、8.7%.结论随着再生粗骨料取代率的增加,再生混凝土梁的抗剪承载力下降,将实测数据进行回归计算,偏于安全的取α=0.16,结合现行规范,提出了再生混凝土梁的抗剪承载力建议公式.

This paper mainly discusses the shear behavior of simply-supported beam using recycled coarse aggregate concrete, and the characters of both shear capacity and diagonal cracking are analyzed. After selecting the artificial method to make the recycled coarse aggregate, the approaches of the research indude making recycled coarse aggregate concrete based on the design approach of blend ratio for common concrete, testing the shear performance of 5 groups of concrete beam with the same section size, percentage of reinforcement and axial compressive strength, and different replacement ratio of recycled coarse aggregate is 0%, 10% ,20% ,30% ,40% respectively. The deflection and diagonal crack width of the recycled concrete beam are similar to those of the common concrete beam, with 4 phases of elasticity, cracking, yielding and ultimate during the stress course of recycled concrete beam component right section stress, but the shear capacity of recycled concrete beam reduces. Under the 4 kinds of recycled coarse aggregate, the shear capacity of recycled concrete beam drops by 1.3% ,2.7% ,4.8% ,8.7%. The test result shows that the shear capacity of recycled concrete beam reduces with the increase of recycled coarse aggregate. With the return computation of the measured date in favor of α =0.16 ,a formula related to the shear capacity of recycled concrete beam is proposed and recommended.