Research On The Interface Bonding Property Between Basalt Fiber Concrete And Old Concrete

This article relies on the technology project of the Guangdong Provincial Department of Transportation,which deals with the repair technology of reinforced concrete bridge structures under uninterrupted traffic.Through basic mechanical tests,shear tests,core pull-out tests,and three-point bending tests,the study of basalt fiber in concrete The influence of the optimum dosage and different factors on the interface bond strength and fracture properties of new and old concrete,and the effect of vibration on the interface properties of new and old concrete.The main work of this article is as follows:Concrete compressive,flexural and splitting tensile tests were conducted to study the influence of different basalt fiber content and different fiber input methods on the basic mechanical properties of concrete.Concrete shear test and core pull-out test were conducted to study the effects of different interface treatment technologies and different maximum particle size of aggregate on the interfacial bond strength between basalt fiber concrete and the old concrete.The three-point bending test of concrete was conducted to study the fracture properties of basalt fiber reinforced concrete and old concrete with different aggregate maximum grain sizes and different repair layer thicknesses.The concrete shear test,core pull-out test and three-point bending test were carried out under slight vibration to study the effect of different vibration time periods on the bond properties of new and old concrete at different bonding surfaces of basalt fiber concrete and old concrete.An analysis of the mechanism of the influence of the bonding properties between the new and old concrete at different vibration time periods.The following conclusions can be drawn:The strength of concrete increases first and then decreases with the increase of basalt fiber content.When the basalt fiber content is 2 kg/m3 and the fiber input method is scattering method,the compressive strength and flexural strength of basalt fiber reinforced concrete are comparable.Splitting tensile strength reaches maximum value;The shear strength and core pullout strength of basalt fiber reinforced concrete and old concrete are getting smaller and smaller with the increase of the maximum aggregate particle size,and the strength reaches the maximum when the interface agent is brushed at the interface.The fracture performance of basalt fiber reinforced concrete and old concrete increases with the decrease of repair layer thickness,but increases with the increase of aggregate maximum grain size.The vibration of the basalt fiber reinforced concrete and the old concrete at the initial stage of 90 minutes after the final coagulation will weaken the bond performance of the interface between the basalt fiber reinforced concrete and the old concrete.Among them,the greatest reduction in the interfacial bondability during the vibration period is from the initial setting to final setting and forming to final setting.In the vibration of 90 minutes,the vibration from the forming to the initial setting will increase when the old and new concrete bonding surfaces are front or side surfaces,and decrease when the bonding surface is the bottom surface.