Concrete Carbonation in Mexico and Spain: DURACON Project, Four Year Evaluation

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Abstract:

This work is part of the DURACON Ibero-American project, which seeks to characterize concrete durability under environmental conditions, based on reinforced concrete sample exposure in at least two different atmospheres (marine and urban), for each of the 11 countries in the project. Specimens were exposed to the environmental conditions of 13 Mexican sites (8 urban and 5 marine atmospheres). Concrete specimens were 15 x 15 x 30 cm, with 6 rebars each, and three concrete covers (15, 20 and 30 cm). Two concrete mixtures were used with water/cement ratios of 0.45 and 0.65, respectively. Six reinforced and six plain concrete specimens were placed on each exposure site. Environmental data was collected on each exposure site, including rainfall, relative humidity, time of wetness, temperature, wind velocity, and carbon dioxide/chloride concentrations. Corrosion rates and potentials, as well as concrete resistivity were measured in the reinforced samples. Carbonation depths were measured on the plain ones. The present work focused on the measurements of environmental parameters during the first two years of exposure to analyze the potentiality and the probability of carbonation-induced corrosion, and the evaluation of the corrosion initiation period for the reinforcing steel on the 13 Mexican exposure sites.

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