Experimental Researches On The Corrosion Resistance Performance Of Magnesium Phosphate Concrete Based Textile Reinforced Concrete Axial Compressed Column

The durability of concrete structures in corrosion environment has received increasing attention in recent years.Commonly used measures to improve the corrosion resistance of concrete structures,including increasing the thickness of concrete protective layer,using high-performance concrete,coated with resin coating or inorganic silane coating on the surface of concrete,and taking advantage of cathodic protection etc.However,these measures have their limitations,Thus this paper proposed the use of potassium magnesium phosphate cement based texttile reinforced concrete(TRC)materials for strengthening of concrete structures in corrosion environment.Taking advantage of high compactness and high strength at early age of potassium magnesium phosphate cement the structure of the periphery to form an effective confine and decreasing the corrosion rate of the structure,thereby enhancing the durability of the structure.The main contents of this paper include:1.Experimental study of TRC sheet mechanical performance in corrosion environmentThe influence of corrosion period and base material on bearing capacity,deformation and crack width of TRC plate was studied by testing the bending performance of TRC sheet in corrosion environment.The results show that the bending performance of the MKPC based TRC plate is 3 times higher than that of the TRC plate of the Portland cement TRC plate.After different corrosion duration,the bending performance of TRC plate of the both base materials decreased.The decrease of the cementitious cement sheet is 16.9% ~ 39.6%,while the decrease of the magnesium phosphate cement sheet is about 8% ~ 17.1%,and the mechanical properties of the magnesium phosphate cement sheet were better than that of the Portland cement sheet.2.Experimental study of the bond behavior of MKPC based TRC confined concrete columns in corrosion environment.The bonding performance of TRC confined reinforced concrete columns in corrosion environment is studied,considering the influence of corrosion rate and corrosion environment.The bonding performance between steel bars and concrete columns in different conditions were tested.The mechanism of the bonding performance in the corrosion environment was analyzed,and the reinforcement performance was evaluated.The results show that the bonding strength of the reinforced specimen at the corrosion rate of 0%,2.5% and 5% is increased by 79%,92% and 176%,respectively,compared with the unreinforced columns.The bond strength is higher than that of the test specimen which does not continue to corrode.The increase rate is 21.9%,8.4% and 6.9% respectively.3.Experimental study on axial compression behavior of TRC confined concrete columns under corrosive environmentBased on the above experiments,the axial compression performance of reinforced concrete columns with potassium phosphate magnesium concrete in corrosion environment was studied and compared with the silicate cement based TRC reinforcement columns.The axial compression performance of concrete columns in different corrosion rate,reinforcement of based material and number of reinforced layers was tested by experiment.The results show that the ultimate bearing capacity of single-layer TRC reinforced columns with corrosion rate of 0%,2.5% and 5% is 15.36%,15.5% and 13.71%,respectively,compared with those without reinforcement.The load carrying capacity of concrete column reinforced by single layer TRC was reduced by 5.22%,4.56% and 6.31% respectively,and the double-layer TRC reinforcement column was reduced by 4.36%,5.06% and 4.88%,respectively,after 26.89% and 26.56% and 26.86% respectively.4.Derivation of calculation formula of ultimate compression capacity of Magnesium potassium phosphate cement-based TRC reinforced columnBased on this,the reduction coefficient of the corrosion rate to the strength is introduced,and the ultimate bearing capacity of the TRC reinforced concrete column is fitted.The calculation formula of the ultimate compression capacity of the TRC reinforced concrete column is deduced.The calculated theoretical values of the formula match the experimental results well.5.Mechanical properties and corrosion resistance enhancement mechanism of magnesium phosphate cement-based TRC confined columnIn this paper,the enhancement mechanism of potassium manganese phosphate cement based TRC was studied.The results show that the TRC reinforcement layer can effectively limit the lateral deformation of the concrete column,and it can work with the core concrete to improve the overall stiffness of the structure during compression process.In addition,in the process of chlorite erosion,the infiltration of water molecules and potassium phosphate magnesium cement continue to hydration reaction,the formation of magnesium phosphate hydrate constantly filling the gap of cement matrix,making the crystal structure becomes more compact,it can effectively inhibit the chlorine Ion infiltration of core concrete,it can effectively block the chloride ions on the erosion of steel.