再生粗骨料混凝土梁抗弯性能研究

目的研究再生混凝土梁正截面受力变形性能和破坏特征与普通混凝土梁的差别.方法参照普通混凝土配合比设计方法配制再生粗骨料混凝土,对4组截面尺寸及配筋率相同,再生粗骨料取代率分别为0、5%、10%、15%的混凝土梁进行抗弯试验.结果再生混凝土梁正截面受力过程中,同样具有弹性、开裂、屈服和极限4个阶段;再生混凝土梁与普通混凝土梁的受弯破坏机理基本相同.在相同条件下,再生混凝土梁的开裂弯矩略小于普通混凝土梁,极限抗弯承载力接近于普通混凝土梁.结论采用现行《混凝土结构设计规范》公式计算再生粗骨料掺入量为5%~15%再生混凝土梁的极限弯矩、开裂弯矩、最大裂缝宽度依然是可行的,但挠度公式需进行调整,乘以1.20倍的系数.

Bend Performances of Recycled Coarse Aggregate Concrete Beam

The goal of the paper is to research the difference between the component right section stress distortion performance and destruction characteristic of the recycled concrete beam and that of the common concrete beam.The approaches of the research included making recycled coarse aggregate concrete based upon the design approach of blend ratio for common concrete;testing the flexural performance of 4 groups of concrete beam with the same section size,same percentage of reinforcement and axial compressive strength,and different replacement ratio of recycled coarse aggregate of 0%,5%,10%,15% respectively.The result of the research shows that like common concrete beam,there are still 4 phases of elasticity,cracking,yield and ultimate during the stress course of recycled concrete beam's component right section stress;the characteristics of stress distortion and destruction of the recycled concrete beam are basically the same as those of the common concrete beam.Under the same conditions,the cracking moment of recycled concrete beam is smaller than that of common concrete beam,the ultimate flexural carrying capability of recycled concrete beam is almost the same as that of common concrete beam.The conclusion of the paper is that it is still feasible to calculate the ultimate bending moment,cracking moment,the biggest crack width of recycled concrete beam with 5%-15% recycled coarse aggregate according to the formula in the Concrete Structure Design Criterion,but the deflection formula needs to be adjusted,multiplied by 1.2 coefficients.