10-year natural carbonation data of concretes with limestone, fly ash, volcanic ash, and slag and exposed to tropical climate in India

The adoption of supplementary cementitious materials (SCMs) as a partial replacement of Ordinary Portland Cement (OPC) is increasing in anticipation of reducing the carbon footprint of cement and concrete industry. The resistance of concretes with SCMs against natural carbonation (a reactive-diffusion mechanism) is still a topic of research. Most literature adopt accelerated carbonation tests (under constant humidity and temperature conditions) to estimate the natural carbonation depth (d_CO2) in concrete. This does not always represent the actual scenario in the field structures. Moreover, accelerated carbonation conditions could result in significantly different pore structure than that are formed in the case of natural carbonation; hence, not always reliable to model the service life. Hence, there is a need for data on long-term natural d_CO2 to help design reinforced concrete for a target service life. The data presented in this paper contains long-term natural d_CO2 data of 45 different concretes prepared using various SCMs like volcanic ash (from Greece), fly ash, slag, and limestone (from France). The concrete specimens were prepared in France, shipped to India by air (in moist burlap and plastic cover), and then kept in sheltered and unsheltered exposure conditions on the terrace of a building in Chennai, India, experiencing tropical climate (warm and humid conditions). The data includes mixture proportions (type of binder, water-to-binder ratio, binder content, % SCMs, fine and coarse aggregate (river sand and gravel) content, and air content). In addition, curing time and compressive strength of concrete mixes are provided in Set A. Sets B and C consist of the natural d_CO2 of concrete measured at various time instances between 1 and 11 years of natural exposure. Arguably, this is the first of its kind natural d_CO2 database from a tropical climate zone. The natural d_CO2 values were measured using a phenolphthalein indicator prepared according to RILEM CPC 18. This data can be used by researchers and practitioners to calibrate the existing carbonation models or to develop new models to estimate natural d_CO2 for concretes exposed to tropical climates. Such models can help design concretes to achieve the target corrosion-free service life for reinforced concrete systems.