Experimental Study On The Chloride Erosion Simulation And Flexural Properties Of RC Beam Strengthened With TRC

Textile reinforced concrete(TRC)has a wide application prospect because of its good crack limiting,corrosion resistance and coordination with concrete structures.And it is especially suitable for the repair and reinforcement of concrete structures in marine environment.At present,there are more researches on the bending performance of TRC-strengthened beam in conventional environment,but less researches on the durability of the beam in chloride corrosion environment,especially in the field of chloride ion transmission,which has not been reported publicly.In order to further verify the feasibility and applicability of TRC in the reinforcement of marine concrete structures,the bending durability of TRC-strengthened beam in chlorine salt dry-wet cycle environment is studied in this paper,which includes the chloride ion transmission performance and the bending mechanical properties,considering the influence of chloride salt concentration,dry-wet cycle times,sustaining load,reinforcement layers and chopped fiber content.Finally,based on the experimental results,the diffusion equation of chloride ions in the TRC reinforced layer under the new boundary conditions is proposed,and the formula for calculating the flexural ultimate bearing capacity of TRC-strengthened beam under the action of chloride salt dry-wet cycle is modified.The specific conclusions are as follows:1)With the increase of chloride concentration,the chloride ion content and diffusion coefficient of TRC increase;With the increase of dry-wet cycle time,the chloride ion content of TRC increases,and the diffusion coefficient decreases.When dry-wet cycle time reaches 330,the microstructure of TRC would be damaged obviously;Load can promote the chloride ion penetration of TRC,making chloride ion content and diffusion coefficient larger,and causing great damage to the microstructure of TRC;Compared with the reinforced beam,the chloride ion content and diffusion coefficient of the unreinforced beam are obviously larger,but the increase of the reinforcement layer has little effect on the chloride content and diffusion coefficient;The addition of a certain amount of chopped fiber is beneficial to improve the chloride penetration resistance of TRC.2)With the increase of chloride concentration,the crack development and deflection change of the reinforced beam are accelerated,and the bearing capacity decreases;When the dry-wet cycle time is less,the influence on the overallmechanical properties of reinforced beam fluctuates.When the dry-wet cycle time reaches 330,the mechanical properties of reinforced beam decrease obviously;When sustained load is small,the performance of the reinforced beam decreases greatly in the aspects of crack,deflection and bearing capacity.When sustained load is large,the mechanical properties of the reinforced beam are improved,and the bearing capacity decreasing amplitude is smaller compared with the beam without sustaining load;Compared with the reinforced beam,the crack and deflection of the unreinforced beams develop faster,and the bearing capacity decreases greatly,especially the cracking load;With the increase of the chopped fiber content,the mechanical properties of reinforced beams are improved.When the chopped fiber content reaches1%,the increase is more obvious.3)Based on the second diffusion law of Fick,the diffusion equation of chloride ion in TRC reinforcement layer under the new boundary conditions is proposed,and the rationality of the diffusion equation is verified by the experimental data.4)Based on the analysis of TRC chloride diffusion coefficient,the calculation formula of bending ultimate bearing capacity of TRC-strengthened beam under the action of chlorine salt dry-wet cycle is modified,and the rationality of the calculation formula is verified by the experimental data.There are 52 pictures,18 tables and 90 references in this paper.