Experimental Study On Shear Performance Of Alkali-resistant Glass Fiber Concrete Beam

With the maturity of steel fiber concrete in theoretical research and practical engineering application technology,alkali-resistant glass fiber reinforced concrete has received widespread attention from scholars at home and abroad for its excellent mechanical properties and environmental protection.However,there is still a lack of standards for the application of alkali-resistant glass fiber reinforced concrete,and the research on alkali-resistant glass fiber reinforced concrete at home and abroad mainly focuses on the basic mechanical properties,durability,high-temperature performance,flexural performance and so on,the research on structural shear performance is relatively small.Therefore,the experimental study on the shear resistance of alkali-resistant glass fiber reinforced concrete beams provides a basis for the establishment of relevant standards and has important reference value for practical engineering applications.This paper firstly carried out the trial test of the alkali-resistant glass fiber content.The fiber content was 0%,1% and 2%,respectively.By comprehensively comparing the compressive strength and splitting tensile strength of concrete standard cube test pieces with different fiber content,the reasonable range of alkali-resistant glass fiber is determined as the fiber content in the alkali-resistant glass fiber reinforced concrete beam test.Then,in this paper,seven alkali-resistant glass fiber reinforced concrete beams and five ordinary concrete beams were tested on shear strength of inclined section under concentrated symmetrical load by static load test method,and the influence of alkali-resistant glass fiber incorporation on shear strength of simply supported concrete beams was analyzed.The variable parameters controlled by the test beam are alkali-resistant glass fiber volume fraction(0%,0.5%,1.0%,1.5%),shear span ratio(?=1,?=2,?=3),and hoop ratio(0.19%,0.25%,0.38%).During the test,the oblique cracking load,the crack development width and regularity,the mid-span deflection change,the stirrup strain,and the ultimate failure load are measured.Through comparative analysis of the experimental phenomena,the characteristics of the inclined section of alkali-resistant glass fiber reinforced concrete beam and shear mechanism were studied.By comparing and analyzing the experimental data of alkali-resistant glass fiber reinforced concrete and ordinary concrete,the influence law of different fiber volume ratio,shear span ratio and reinforcement ratio on shear performance of concretebeams is obtained.Based on the existing research,an empirical formula for the cracking load calculation formula and shear ultimate bearing capacity of alkali-resistant glass fiber reinforced concrete beams is given.Test shows that the shear failure process of alkali-resistant glass fiber reinforced concrete beam is basically the same as that of ordinary concrete beam.The introduction of alkali resistant glass fiber can effectively increase the inclined cracking load of concrete beam,which has obvious inhibiting effect on the development of concrete beam crack,but the lifting of ultimate load is limited.The increase of fiber incorporation on the cracking load of inclined section does not increase with the increase of fiber volume rate,and the effect of proper fiber content is better.In this test,the effect is best when the fiber volume rate is 1%.The shear-strengthening effect of alkali-resistant glass fiber on the concrete beam is greatly affected by the shear span ratio,and the increase of the cracking load of the oblique section increases with the increase of the shear span ratio.