ACCELERTED TESTING OF DETERIORATED CONCRETE STRUCTURES DUE TO CARBONATION

T. Chandrasekaraiah, H. Anantharam, Krishnamurthy M, K. V. Manjunath, M.N. Hegde

Abstract: Normally in reinforced concrete structures, the reinforcing steel is well protected against corrosion by concrete. The reinforcing steel remains passive under high alkalinity. However, the highly desirable durability requirement is not always achieved in practice due to various environmental factors. Corrosion of reinforcement in concrete is a common cause of deterioration in many RC structures. Two main cause of corrosion of reinforcement in concrete are: Carbonation and presence of Chloride ions. Carbonation is the result of the chemical reaction between carbon dioxide gases in the atmosphere and alkaline hydroxides in the concrete. The rate of carbonation depends on the thickness of the concrete cover and also on its quality in terms of the mixing ratios that achieve the highest quality. The relative humidity and temperature mainly affects the carbonation of concrete. Permeability, nature and intensity of cracks, and cover thickness will influence the initiation and sustenance of reinforcement corrosion. The expansion of the corroding steel causes surface cracking and subsequent spalling of the cover concrete.

Keywords: This paper presents the experimental results of the work carried out on carbonation of concrete M30 and M40 grades with different CO2 concentration and exposure period.

DOI: https://doi.org/10.15623/ijret.2014.0318004