Research On Mechanical Properties Of GFRP Reinforced Glass Fiber High Performance Concrete Bidirectional Slab

Glass Fiber Reinforced Polymer bars have corrosion resistance,high strength,thermal expansion coefficient close to concrete material,insulation and other properties.Using Glass Fiber Reinforced Polymer bars,which abbreviated GFRP bars to replace part of traditional steel reinforcement in concrete slab can effectively improve the structural durability.It is suitable for Marine engineering,underground engineering,power transmission engineering and other special engineering structures.At present,there are few researches on the mechanical properties of HPC slabs equipped with GFRP bars at home and abroad,and no mature methods for calculating the bearing capacity and deformation have been formed.In this paper,the punching bearing capacity and deformation of GFRP reinforced HPC two-way slabs are studied by both experimental and theoretical analyses.The main contents of this paper are as follows:Based on the material and structural properties,the GFRP reinforced HPC bidirectional slab tests are designed and carried out.The influence of the reinforcement type（both GFRP bars and steel bars）and the glass fiber content on the mechanical properties of HPC are analyzed.The failure modes of HPC bidirectional slabs with GFRP bars and HPC bidirectional slabs with steel bars are observed.The load-deflection curves,strains at each measuring point of the reinforcement bars and the concrete slabs are analyzed,respectively.The punching bearing capacity and deformation capacity of these novel slabs are also analyzed.With the increase of glass fiber content,the ultimate bearing capacity of concrete slab increases by 27.98%when the glass fiber content increases from 0%to 0.15%.When the fiber content exceeds 0.15%,the ultimate bearing capacity of concrete slab decreases.The best content of glass fiber is 0.15%.It is obvious there are similarities between GFRP reinforced HPC bidirectional slabs and reinforced HPC bidirectional slabs in the process of stress.Based on the theory of steel reinforced concrete slabs,the applicability of calculation assumption and calculation method of anti-punching shear capacity of GFRP reinforced HPC bidirectional slabs is discussed and demonstrated.The equivalent reinforcement ratioρ_eq is used to calculate the punching bearing capacity of GFRP reinforced HPC bidirectional slabs,and the results are compared with those calculated in national codes.HD camera is used here to record the crack development process of HPC bidirectional slabs with load,and crack width is gained based on image processing method.Based on the test results,the deflection checking of GFRP reinforced HPC two-way slabs are carried out.Two thresholding methods are used to calculate the crack width of HPC bidirectional slabs,and the deflection calculation of GFRP reinforced HPC bidirectional slabs is completed.The analysis shows that the crack widths obtained by the two thresholding methods have a small difference,and the ratio of them is around 1.