Accelerating carbonation in lime-based mortar in high CO2 environments

Abstract

To accelerate the carbonation of lime, mortar samples were cured in chambers with high CO2 concentration. Two types of lime mortar were prepared, which are similar to Roman mortar types: lime and standard sand (M1) and extra ceramic dust and fragments (M2). After demolding, half of the samples were placed in the climate chamber where conditions were constant (20 °C, 60%, 1600 ppm) for six months, and the rest were left in laboratory conditions (25 °C, 34%, 703 ppm). The carbonation of the samples was evaluated at 28, 90, 120 and 180 days as well as microstructural, physical, hydric and mechanical properties. CO2 curing had pronounced effects on both types of mortar. M2 mortar samples showed advanced calcite precipitation and early improvement in various properties. At later stages, cracks caused drops in those properties.