Background:

The durability of reinforced concrete structures can be affected by corrosion of reinforcing steel due to carbonation. Under the assumption that the concrete will have a behavior equivalent in situ, an index of durability can be obtained when the concrete is exposed to accelerated carbonation tests. The aim of the present work was establish a reliable prediction from correlations between tests of carbonation of concrete exposed to accelerated and natural environments.

Methods:

Prismatic concrete specimens 50x50x250 mm elaborated with two types of cement OPC and PCC (respectively, ordinary Portland cement and Portland cement composite) and three different water/cement ratios (0.6, 0.7 and 0.8) were tested. A set of specimens were exposed to accelerated carbonation in an environment of 3, 4, 5 or 6% CO2 and 50 - 60% RH at 30 °C. Another set were exposed in two urban areas in the metropolitan area of Monterrey. The carbonation progress was monitored regularly in every environment of exposure and then was compared with predictions obtained from the results of the accelerated environment.

Results:

All specimens analyzed in this research showed a greater depth of carbonation, compared with predictions suggested in the scientific literature, so the application of the equation based on the square root of time should be reviewed, the phenomenon of carbonation is a more complex process than could be described by this method.

Conclusions:

The results showed a good correlation to the prediction based on a linear trend carbonation progress from accelerated tests.

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