Study On Corrosion And Technology Protection Of Steel Rebar In Concrete

Corrosion of steel rebar in concrete becomes a main reason for the premature degradation of reinforced concrete, which is by far the most widely used construction material in the modern society. So more and more scholars and engineering technical staff pay close attention to the problem. Obviously, reinforced concrete breakage is steel electrochemistry corrosion,under the concrete's protecting floor, before the offspring of corrosion of rebar bulge crack,the medium of corrosion surrounding is inrushing penetrability through the concrete's protecting floor. Based on the predecessors' research, some problems of the Corrosion of steel rebar in concrete are studied in this paper and the actual work done is as follows:In the previous research, there was a little work on influence of Dura fibre and modified polypropylene fibre on corrosion of rebar in concrete. In this paper, the effects of Dura fibre and modified polypropylene fibre on the mechanical properties, carbonation of reinforced concrete have been studied systematically. Corrosion behavior was investigated by electrochemical methods, and experimental data was discussed by the curve fitting as a powerful tool to data processing and get a function expression which shows the relation between the variables and analyses them. The compression test shou that, because of Dura fibre and modified polypropylene fibre, its compression strength is bigger than steel rebar's potential without fibre in concrete, The compression strength was found to increase with increase in the Dura fibre and modified polypropylene fibre fume content; The other results show that, because of Dura fibre and modified polypropylene fibre ,its potential is bigger than steel rebar's potential without fibre in concrete, The potential was found to decrease with increase in the Dura fibre and modified polypropylene fibre fume content; Dura fibre and modified polypropylene fibre does not reduce the mechanical properties, but the reinforced concrete with Dura fibre and modified polypropylene fibre has resistance to corrosion of rebar, and the best quantity added to is not preponderate over 1Kg/m³ in concrete; The carbonation depth was found to decrease with increase in the Dura fibre and modified polypropylene fibre fume content; the corrosion was found to decrease with increase in the Dura fibre and modified polypropylene fibre fume content by electrochemical methods, the numerical value of half–cell potential of reinforcement is less, because the meeting of Dura fibre which preventing the crack of concrete bringing and the fountain of crack, decreasing the bug of concrete, improving character of concrete and advancing the closing of concrete. This is decreasing the speed of Cl,O₂,H₂O diffusing in concrete which is leading to decrease the speed of electrochemistry corrosion.Corrosion inhibitor for reinforcing steel was considered as one of best methods, but the best inhibitor for reinforcing steel usually need purchase from developed countries, and the best inhibitor in concrete is expensive, it is influence the generalize the use of inhibitor in China. Now, Na₂MoO₄·2H₂O have get good application of inhibitor to concrete. As a result of the good effect of decreasing the speed of electrochemistry corrosion, in this paper, inhibitor consisting of sodium molybdate was discussed through empirical research. The inhibitor contain sodium. The inhibitor is about Na₂MoO₄·2H₂O, C₄H₁₃N₃, C₄H₈N₂S, C₄H₆O₂,. By making series concrete specimens after acceleration corrosion, the best directions for producing chemicals inhibitor is Na₂MoO₄·2H₂O, 0.3g/L; C₄H₁₃N₃, 30mL/L; C₄H₈N₂S, 1.6g/L; C₄H₆O₂, 2g/L. the steel bar corrosion degree was ascertained by electricity chemistry method Simultaneity, comparison study on the concrete specimens appending inhibitor was carried out. By weight corrosion and half cell potential method, polynomial corrosion behavior was investigated. In this paper, the influencing factors of basic properties of reinforcing steel bar were discussed by orthogonal design experiments. The optimized mix ratio of high anti-corrosion admixture component has been determined,and the optimized mix ratio of high anti-corrosion admixture were confirmed by repeat experiment. The result indicated that, the optimal inhibitor had a good effect in concrete, the optimal inhibitor was obtained, validate experiment proved that the optimal inhibitor had optimal reiteration and anti-corrosion, established the truth of experiment. In addition, experiment indicated that anti-corrosion in the steel bar was ill defined when fibre and inhibitor was joined synchronously. When fibre and inhibitor was joined all together, its potential is bigger than steel rebar's potential without fibre and inhibitor in concrete, and get the best combination of fibre and inhibitor.