RELATIONSHIP BETWEEN RESULTS OF ACCELERATED AND NATURAL CARBONATION IN VARIOUS CONCRETES

摘要

This paper presents part of the results of an experimental study performed at the Civil Engineering Technological Center of FURNAS Centrais Eletricas (Goiania), which was the object of a master's degree dissertation conducted in the Master's Program in Civil Engineering of the Federal University of Goias. The paper presents a comparison of results of accelerated and natural carbonation in various concretes, which were produced using six binary mixes of Portland cement CPII F with each of the following addition contents: 10% of silica fume, 10% of metakaolin, 10% of rice husk ash, 25% of fly ash, 65% blast furnace slag and reference (without addition); with two curing procedures (wet and air curing) and three water/binder ratios (0.40, 0.55, 0.70). These concretes underwent an accelerated carbonation process (in climatic test chamber with a CO_2 content of around 5%) in parallel with natural carbonation monitoring. As the main result it was noted that the coefficients of accelerated carbonation were five times higher than the coefficients of natural carbonation, featuring good correlations between those two types of attack. Furthermore, the results obtained experimentally were confronted with carbonation estimation models (mathematical models), in which it was observed that the direct relationship presented by those models cannot be generalized.