纤维编织网增强地聚物砂浆加固钢筋混凝土梁受剪性能研究

SHEAR BEHAVIOR OF RC BEAMS STRENGTHENED WITH TEXTILE REINFORCED GEOPOLYMER MORTAR

为研究纤维编织网增强地聚物砂浆(TRGM)加固钢筋混凝土构件的可行性,首先通过双剪试验探讨了地聚物砂浆与碳纤维编织网在常温下和高温后的粘结性能,随后开展了地聚物砂浆粘贴不同层数(1层、2层、3层)碳纤维编织网抗剪加固钢筋混凝土梁的静载试验,并与未加固梁、环氧树脂粘贴碳纤维编织网抗剪加固混凝土梁进行了试验比较。试验结果表明,地聚物砂浆与碳纤维编织网的常温粘结强度达2.02 MPa,在温度不高于300℃时强度退化不显著;在未采取任何锚固措施的情况下,采用地聚物砂浆粘贴单层碳纤维编织网加固梁的抗剪承载力相比于未加固梁提高47.1%,提高幅度约为采用环氧树脂粘贴加固的一半;两层TRGM加固梁中的纤维作用发挥得最充分。最后,提出了TRGM抗剪加固梁斜截面承载力的简化计算模型,模型计算结果与试验结果吻合较好。

To investigate the feasibility of using textile reinforced geopolymer mortar(TRGM)to strengthen concrete members,the bond strength of geopolymer mortar with carbon fiber textile was tested at ambient temperature and after exposure to elevated temperatures,through double shear tests.Then static load tests were conducted on RC beams shear strengthened with different layers of TRGM(1layer,2layers and3layers).Also,one unstrengthened beam,and one shear strengthened beam with textile using epoxy resin as adhesive,were tested for comparison.Test results show that the bond strength of geopolymer mortar with carbon fiber textile at ambient temperature reached 2.02MPa,and that no significant strength degradation occurred at a temperature not higher than 300℃.Compared to the unstrengthened beam,the shear bearing capacity of the RC beam strengthened by a single layer of TRGM,without special anchorage measures,is increased by47.1%.This increasing extent is about one half of that of the beam strengthened with textile using epoxy resin as adhesive.The highest strengthening effectiveness is achieved in the beam strengthened by two layers of TRGM,in which the tensile strength of fibers was fully utilized.Finally,a simplified model for calculating shear bearing capacity of TRGM strengthened RC beams is proposed,and the calculated results using this model agree well with the test results.