Carbonation depth estimation in reinforced concrete structures using revised empirical model and oxygen permeability index

Corrosion of rebar is one of the major deteriorating mechanisms that affect the durability of reinforced concrete (RC) structures. The increase in CO2 concentration in the atmosphere leads to early carbonation and deterioration due to corrosion in RC structures. In the present study, an attempt has been made to modify the existing carbonation depth prediction empirical model. The modified empirical model is verified from the carbonation data collected from selected RC structures of CSIR-SERC campus, Chennai and carbonation data available from the reported literature on in-situ RC structures. Attempt also made to study the carbonation depth in the laboratory specimens using oxygen permeability index (OPI) test. The carbonation depth measured from RC structures and laboratory specimens are compared with estimated carbonation depth obtained from OPI test data. The modified empirical model shows good correlation with measured carbonation depth from the identified RC structures and the reported RC structures from the literature. The carbonation depth estimated from OPI values for both in-situ and laboratory specimens show lesser percentage of error compared to measured carbonation depth. From the present investigation it can be said that the OPI test is the suitable test method for both new and existing RC structures and laboratory RC specimens.

Automated summary

Corrosion of rebar is a significant deteriorating mechanism affecting the durability of reinforced concrete structures. This study aims to modify the carbonation depth prediction empirical model and verify it using carbonation data from selected RC structures and literature. The effectiveness of the oxygen permeability index (OPI) test in estimating carbonation depth in laboratory specimens and in-situ structures is also explored. The modified empirical model shows good correlation with measured carbonation depth, and the OPI test proves to be a suitable method for assessing carbonation depth in both new and existing RC structures.