CFRP加固钢筋再生混凝土梁的弯曲性能研究

Flexural behavior of RC beams made with recycled aggregate concrete and strengthened by CFRP sheets

为研究再生混凝土梁的弯曲性能,进行了钢筋再生混凝土梁及其经CFRP加固后的受弯性能试验研究,分析了再生粗骨料取代率和CFRP加固层数对再生混凝土梁受力性能的影响,比较了钢筋再生混凝土梁加固前后的挠度和裂缝扩展情况。试验结果表明:再生混凝土梁的变形能力和受弯承载力较普通混凝土梁没有明显降低,但其刚度和延性均有所降低,可通过CFRP加固提高其刚度和极限荷载,但不能改善其变形能力;CFRP加固层数对钢筋再生混凝土梁的开裂荷载、屈服荷载和极限荷载影响较大,其中极限荷载受加固层数影响最大。通过理论计算和有限元分析,建立了钢筋再生混凝土梁及其经CFRP加固后的受弯承载力计算式,理论计算结果与钢筋再生混凝土梁的试验结果符合较好。研究成果可为再生混凝土梁的工程应用提供参考依据。

To investigate the flexural behavior of reinforced recycled aggregate concrete (RAC) beams,experimental studies were conducted and test parameters included replacement ratio of recycled coarse aggregate (RCA) and layers of carbon fiber reinforced polymer (CFRP) sheets. The deflection and crack development of reinforced recycled aggregate concrete beam before and after strengthening was compared. The results show that there is no obvious difference in ultimate load and deformability of the beams with or without RCA replacement,but the stiffness and ductility of the beam degrade with the RCA replacement. However,except for deformability,the stiffness and load carrying capacity can both be improved by CFRP reinforcement. The results also show that the crack load,yield load and the ultimate load all increase with the increasing layers of CFRP reinforcing arrangement,and among the effect of CFRP strengthening,the ultimate load is most pronounced. In addition,the theoritical calculation and finite element analysis to estimate the ultimate load for the CFRP strengthened beams are presented and the results agree well with the experimental ones,which can be used as a valuable reference for the application of recycled concrete beams in civil engineering.