Experimental Study And Theoretical Analysis Of Short Cylinder Reinforced With GRC Mesh And Polypropylene Concrete

The short plain concrete columns strengthened with GRC mesh cloth and polypropylene concrete can make full use of the characteristics of glass fiber cloth such as strong tensile strength,corrosion resistance,penetration resistance,wear resistance,crack resistance and impact resistance.For some members whose bearing capacity and ductility need to be greatly strengthened,the single reinforcement method has different limitations.Therefore,this paper proposes a composite reinforcement method to make up for the shortcomings of single material reinforcement to meet the requirements of engineering application.Based on this,the axial compression behavior of short plain concrete columns strengthened with GRC mesh and polypropylene concrete composite is studied.The results are as follows:1.The axial compression behavior of 24 plain concrete columns was studied in this paper.The parameters include the GRC mesh packing position and mode and the content of polypropylene fiber in the reinforced concrete.The failure modes,load-strain curves and load-deformation curves are obtained.The failure mechanism,deformation characteristics and strain changes are studied.The effects of the wrapping position of GRC mesh cloth,the wrapping mode of GRC mesh cloth and the content of polypropylene fiber in the reinforced concrete on the compressive failure mechanism and bearing capacity of the columns are analyzed.The results show that the failure modes of the specimens include oblique shear failure and central crushing.Most of the specimens have concrete peeling off the strengthened layer and GRC grids are fractured vertically.The load-bearing capacity of the full-packed specimens with GRC mesh cloth is higher than that of the partially wrapped specimens;the load-bearing capacity of the specimens wrapped with GRC mesh cloth on the concrete surface of the strengthened layer is higher than that of the specimens wrapped on the existing column due to the interfacial bonding problem;with the increase of the volume fraction of polypropylene fiber in the concrete of the strengthened layer,the load-bearing Carrying capacity has been enhanced,but the increase is relatively small.GRC grid cloth and polypropylene fiber can greatly improve the ductility of components and delay the expansion of cracks.2.Based on the failure mechanism of the specimens,a reasonable assumption and strength model are introduced to calculate the normal cross-section compressive bearingcapacity of specimens confined by zonal fiber bundles under full-envelope condition.The calculated values are compared with the experimental values.The test value is less than the calculated value and has a certain safety reserve.It can be used as a reference for engineering design.