Experimental Study On Performance Of Corroded R.C. Components

The corrosion of reinforcing steel bar in the concrete structure is the research topic that the engineering field pays much attention to. As for the development of society and economy, it is very important to find out the relationship between the cracking distribution and corrosion degree. As a subtopic of the project "parameter identification and system simulation assessment of R.C. structures with damage due to corrosion and cracking", supported by National Natural Science Foundation of China(No.50079002), experimental test of corroded R.C. components in some environment was conducted in this paper.There are different kind of experiment were carried out, such as the experiment with outdoor mixed brine, the rapid corrosion with electrochemistry and the experiment under marine environment. The relationship of the cracking distribution and corrosion degree was summarized by observing the change of corrosive cracking distribution in different environment. Mechanical experiments was carried out on the 8 corroded R.C. slabs that had served 7 years in the marine environment. The effect of corrosion on the mechanical performance of slabs was researched. The result of slabs that had served 7 and 5 years was compared. The change with time of corrosion degree and mechanical performance was researched.Main conclusions are summarized as follows:1.The corrosion cracking with thin concrete cover is vertical, while the corrosion cracking with thin concrete cover is both vertical and inclined.2.The vertical cracking mostly extends from outside to inside, while the inclined cracking extends both from outside to inside and from inside to outside. With the same concrete cover, the vertical cracking appears earlier.3.In the experiment of outside mixed brine, the corrosion degree in the top is higher than that in the middle of steel bars. In the experiment of electrochemistry corrosion, the corrosion degree decreased gradually from the top to bottom along the cracking. The corrosion degree of steel bars is uniform if there is no crack.4.In the 3 different experiment of corrosion, the relationship between corrosion degree and cracking distribution is stable. When the corrosion degree range is between 5% and 20%, the crack width changes linearly with it.5.After the reinforcing bar was corroded, the flexural carrying capacity was degenerated non-linearly with the degree of corrosion. The greater the corrosion degree, the lager loss the flexural bearing capacity. The deformation at the middle of the span of the slab increases linearly with the degree of corrosion. The calculated method to carrying capacity in actual code is not valid for the corroded slabs, but it could be recised.