Chloride Resistance And Anti-corrosion Of Reinforcement Of Concrete With Min-Eral Admixtures

Corrosion of reinforcement taking place in concrete member is a significant source to cause the durability loss and failure of concrete structures when served in chloride environment.Mineral admixtures due to its great environ-ment-friendly superiority and pozzolanic activity has so far been widely applied to engineering structures such as harbor docks and cross-sea bridges.In this pa-per,targeting concrete with mineral admixtures introduced,several experiments including electromigration test for diffusion coefficient of chloride ions in con-crete and accelerating corrosion test by soaking completely and electrifying had been launched,followed by analyzing chloride resistance and anti-corrosion ca-pacity of mineral admixtures concrete specimens,and a corresponding multi-ple-factor model had also been built thereafter for that.The main work and rela-tive concluding remarks are as follow:1.By means of applying orthogonal experimental design,a batch of con-crete specimens were produced by introducing varying water-to-binder ratios and different mineral admixtures combination,and were taken for subsequent test of electromigration for diffusion coefficient of chloride ions in concrete specimens and test of accelerating corrosion by soaking completely and electri-fying respectively.The results revealed that water-to-binder ratio and quantity of fly ash as well as mineral fume could significantly affect the chloride resistance and anti-corrosion capacity of reinforced concrete specimens with mineral ad-mixtures introduced.In this regard,the combination of mineral admixtures with a 50%total amount and a ratio of 1 over 4 between amount of fly ash and min-eral powder showed the best chloride resistance.With regard to anti-corrosion capacity of specimens,a combination of mineral admixtures with a 40%total amount and a ratio of 1 over 1 performed best eventually.2.In accordance with the tested magnitude of electric current in accelerat-ing corrosion experiment for reinforcement,a cumulative electricity had been calculated to analyze the correlation between cumulative electricity and corro-sion rate of reinforcement.The results indicated that for each combination of mineral admixture concrete specimens,a great linear correlation was witnessed between cumulative electricity and corrosion rate,which kindly satisfied Fara-day rule well.Based on this rule,a further analysis had also been done to under-stand the correlation between theoretical corrosion rate of reinforcement,calcu-lated from cumulative electricity,and that actual value,obtained from practical test.The result showed a relative high matching degree between theoretical cor-rosion rate and actual tested value for each combination of concrete specimens,accordingly demonstrated the reasonability of this experiment progress and cor-responding analyzing remarks.3.Based on multiple linear regression analysis and data collected from or-thogonal experiment,a multiple-factor model as well as a second-order polyno-mial model had been built for corrosion rate of reinforcement in mineral admix-ture concrete,and a further significance test and a predicting analysis for ex-perimental data were also performed in purpose of verifying the reasonability of predicting model built in this thesis.The results indicated that as compared to linear model,second-order polynomial model is superior to that when predicting corrosion rate of reinforcement in concrete member with mineral admixture in-troduced.4.For reinforced concrete with mineral admixtures introduced,its chloride coefficient fairly correlated to the corresponding corroded rate,and the rein-forced concrete possessing stronger chloride resistance generally performed better when subjected to corrosion as well,which indicated that lowering chlo-ride coefficient of reinforced concrete with mineral admixtures introduced is an effective measure to improve its anti-corrosion capacity.