Carbonation process in lime pastes with different water/binder ratio

Abstract

Most research on binder carbonation is based on the analysis of depth changes in the carbonation front. Moreover, previous studies have dealt with mortars, where aggregates play a role in the variations in carbonation patterns. In the approach adopted in the present study, carbonation was determined in terms of the variation in weight resulting from CO2 absorption, and a new parameter (independent of the drying process), denominated A, was established. This parameter was assessed in several lime pastes with different W/B (water/binder) ratios and its variations were correlated to paste microstructure. Due to the type of porosity prevailing in lime pastes, diffusion took place according to Fick's law; water was retained not by capillarity but by surface adsorption. Drying did not retard carbonation in lime pastes