Experimental Study On The Flexural Behavior Of CF30 Strength Steel Fiber Full-lightweight Concrete T-beams With HRB500 Steel Bars

Lightweight aggregate concrete is characterized by its high strength,light weight and good durability.Using lightweight aggregate concrete for pouring in the construction of long-span bridge structures and ultra-high buildings will greatly reduce the dead weight of the structure,and the corresponding material consumption will also be reduced,this is of great significance to the acceleration of construction speed and the extension of construction life.By combining full-lightweight concrete with steel fiber,adding steel fiber into concrete matrix can significantly improve its mechanical properties.At present,the research on steel-fiber lightweight aggregate concrete is still not perfect.Meanwhile,it is also of great theoretical significance to research the performance of steel-fiber lightweight aggregate concrete after matching and cooperating with high strength reinforcement bar.In this paper,the flexural behavior of 8 HRB500 reinforced steel fiber full-lightweight concrete T-beams is tested.The bending test process and results of test beam are studied,the influences of steel fiber content on the loading process,concrete strain,steel bar strain,bending moment-deflection curve and crack spacing and width are analyzed.The results show that the incorporation of steel fiber can enhance the ultimate bearing capacity of the beam and give full play to the bending and deformation capacity of the longitudinal reinforcement,and the higher the steel fiber content is,the greater the bending deformation of the longitudinal bar will be,and the ductility of the beam will be significantly improved.At the same time,the steel fiber can restrain the development of cracks and improve the deformation and cracking of the components.Based on the experimental data and theoretical research,this paper discusses the formula for calculating the flexural bearing capacity of the reinforced steel fiber full-lightweight concrete T-beams.The applicability of the formula for calculating the ultimate bearing capacity of the reinforced steel fiber full-lightweight aggregate concrete T-beams to the existing code is verified and the formula for calculating the maximum crack width and section stiffness of the reinforced steel fiber full-lightweight concrete T-beams is established,and the results were compared with the experimental data.It lays a theoretical foundation for the popularization and application of steel fiber full-lightweight concrete structural component in engineering.