Bending And Shearing Behavior Of Hybrid Fiber Self-compacting Concrete Beam With BFRP

As the corrosion problem of steel bars becomes more and more serious,people gradually pay attention to light,high-strength and corrosion-resistant Fiber Reinforced Plastic(FRP)reinforcements.The researches on FRP reinforcements of domestic and foreign scholars mostly focus on the non-stirrup beams and hybrid Steel/FRP reinforcement beams.There is little research on the full FRP bars.Furthermore,hybrid fiber self-compacting concrete,as a new type of high-performance building material,can give full play to the advantages of both fiber reinforced concrete and self-compacting concrete on account of its better performance.The self-compacting concrete is used as the matrix,and the fiber volume and ratio are variables combined with the Basalt Fiber Reinforced Plastic(BFRP)reinforcements.In order to meet the demand of building durability in coastal areas,it is of engineering significance and value to study the self-compacting concrete structure of BFRP reinforcement.In the paper,the blending ratio of self-compacting concrete matrix is firstly tested.The basalt fiber and polypropylene fiber are mixed into the best matrix in different proportions.The basic mechanical properties of the hybrid fiber self-compacting concrete are studied.On this basis,five bending tests of BFRP reinforced hybrid fiber self-compacting concrete beams and ten shear tests of BFRP reinforced hybrid fiber self-compacting concrete beams were carried out.In the bending test study of five BFRP reinforced hybrid fiber self-compacting concrete beams,the effects of total fiber volume,hybrid fiber ratio and longitudinal reinforcement ratio on the bending performance of the beam were analyzed.The following aspects were analyzed: The test phenomena and failure modes are expounded,the load and deflection curves are established,the cracking and ultimate load of the beam are compared,the flat section assumption of the beam is verified,and the characteristics of the top concrete strain,longitudinal reinforcement strain and crack development are analyzed.In the shear test study of ten BFRP reinforced hybrid fiber self-compacting concrete beams,the effects of total fiber volume,hybrid fiber ratio and stirrup ratio on beam shear performance were analyzed.Specially,the following between load and deflection of beam,fiber mixing ratio,total fiber volume,the influence on deflection of beams with or without stirrups in the shear-span,the shear section assumption,longitudinal reinforcement and stirrup strain.The theoretical analysis of the normal section bending of the existing FRP reinforcement beam and the shearing mechanism of the oblique section are carried out.The applicable formula is used to analyze the applicability of the bearing capacity formula of the beam.