玄武岩纤维筋全再生混凝土无腹筋梁受剪性能试验研究

通过4根玄武岩纤维筋与4根钢筋再生混凝土无腹筋梁的受剪试验,研究采用100%粗骨料取代率的再生混凝土梁的裂缝开展、破坏等情况;分析不同纵筋类型下,剪跨比、纵向配筋率和混凝土抗压强度对梁开裂荷载、极限承载力和跨中挠度变化的影响。比较中国规范(GB 50608—2010)、美国规范(ACI 440.1R-06)、加拿大规范(CSA.S 806-12)中规定的计算方法对玄武岩纤维筋再生混凝土梁受剪承载力的适用性。研究结果表明:钢筋再生混凝土梁的受力性能类似于传统的钢筋混凝土梁,而玄武岩纤维筋再生混凝土梁在荷载作用下,裂缝扩展较快且宽度更大;中国规范(GB 50608—2010)对试验梁抗剪承载力的计算值过于保守,美国规范(ACI 440.1R-06)最为接近,加拿大规范(CSA.S 806-12)次之。

EXPERIMENTAL STUDY OF THE SHEAR PERFORMANCE OF BFRP-REINFORCED RAC BEAMS WITHOUT STIRRUPS

According to the shear tests of 4 basalt fiber reinforced polymer (BFRP) reinforced recycled aggregate concrete (RAC) beams without stirrups and 4 recycled concrete beams without stirrups,the failure modes and cracking patterns for recycled concrete beams of which recycled coarse aggregate replacement ratio for 100％ were observed.The influence of shear span ratio,reinforcement ratio,and concrete compressive strength on the cracking load,ultimate bearing capacity and deflection of the beams with different types of longitudinal reinforcement were also analyzed.The test results were compared with shear design equations of the GB 50608-2010,the ACI-440.1R-06 and the CSA.S 806-12 guidelines.The results indicate that the behavior of recycled concrete beam is similar to that of ordinary concrete beam,yet the crack propagation and crack width are faster and wider for recycled concrete beams reinforced with BFRP bars.And,shear design equations of the ACI-440.1R-06 and the CSA.S 806-12 codes provided quite close predictions.However,the predictions of GB 50608-2010 were over-conservative.