Study On Mechanical Properties Of Bond And Anchorage Of Glass-PVA Fiber Reinforced Concrete And Steel Bars

At present,concrete is still the most widely used building material,but its durability is a serious problem in the field of concrete engineering,resulting in more and more obvious engineering building damage.With the continuous improvement of fiber modified concrete technology,existing research and practical projects have proved that the durability of metal fiber,synthetic fiber and other admixtures mixed with cement matrix can be significantly enhanced.To improve the service life of concrete,this measure has become one of the effective means to improve the performance of concrete.As a new type of composite material,Glass-PVA hybrid fiber reinforced concrete can obviously prevent the development of initial internal micro-cracks caused by development speed of macroscopic cracks and improve their strength.Toughness,impact resistance and crack resistance.At the same time,PVA fiber can be used as a carrier so that Glass fiber can be evenly dispersed in the concrete matrix.As a new composite material,it is still in the stage of deep exploration,and its future development and application can’t be overlooked.However,there are few reports on the constitutive relationship of G-PHFRC.Meanwhile,there is a lock of quantitative research on mechanical properties parameters of hybrid fiber concrete and bond properties of steel bars.The work of this paper is divided into the following parts:(1)Relying on the orthogonal test method,three variables,namely,the proportion of Glass fiber,the proportion of PVA fiber and the strength grade of concrete,were controlled,and three horizontal parameters were selected for each factor.The influence of the three factors on the mechanical properties of the concrete matrix was recorded and analyzed through the experimental study of the compressive,flexural and splitting properties of the fiber reinforced concrete.The test results show that the compressive strength of concrete with fiber decreases,but its flexural and splitting tensile strength increases obviously.Compared with the failure state of standard concrete,the blocking effect of adding fiber improves the integrity of concrete components and enhances the toughness of concrete.(2)The constitutive model of bond slip at home and abroad is summarized,and the bond slip test database of steel and concrete is established to facilitate the analysis of its calculation method and influencing factors.(3)Loading tests were carried out on 20 single-end center-pulled specimens,and the load-slip curves measured were recorded to analyze the influence of parameter changes on the bond-slip properties and failure modes of the components.Based on the corresponding characteristic values extracted from the test curve and combined with theoretical analysis,the statistical formula of the bond slip constitutive relation between G-PVA fiber concrete and steel bar was deduced.The calculated bond stress fitted well with the experimental bond stress within the allowable error range,which confirmed the reliability of the test.