Experimental Study on Carbonation of Concrete with Different Dimensional co2 Ingress

Concrete alkalinity protects the reinforcement bars from corrosion but the carbonation phenomenon significantly contributes to the destruction of their passive coating, thus favouring the corrosion onset. Carbonation of concrete decreases the pH value of the concrete which can initiate the corrosion of reinforcements. Reinforcement corrosion is mainly responsible for reinforced concrete degradation. The parameters like dimensional carbon dioxide ingress, duration of carbon dioxide ingress, grade of concrete and volumetric concentration of CO2 are consider for this thesis work. After 28 days curing, specimen were placed in the chamber having supply of carbon dioxide gas. The specimens after exposed in carbon dioxide chamber for two different duration is 145 hours and 290 hours. Then the specimens were cut at 1cm, 2cm and 3 cm respectively from the concrete surface. Those concrete specimens were crushed, powdered, sieved by 90m sieve and the powder which passed through the 90m sieve was collected as sample powder. Carbonation depth has been analysed using phenolphthalein indicator and Fourier Transform Infrared Technique (FT-IR). The measurement of carbonation depth using Infrared spectroscopy was done by referring the characteristic peak of the C-O bonds from the sample powder. The measurement of carbonation depth using the phenolphthalein solution was carried out by spraying the indicator on the split surface of the concrete specimens