Assessment of the Compressive Strength of Lime Mortars with Admixtures, Subjected to Two Curing Environments

Abstract

This article presents the assessment of the compressive strength of three types of lime mortar, one without admixture and the remaining two added with metakaolin and brick dust. The chemical composition of the lime and the pozzolans was evaluated using the X-ray fluorescence (XRF) technique. The mortars were subjected to two curing conditions: humidity and temperature-controlled chamber, and accelerated carbonation chamber, then they were tested at ages of 7, 28, 60 and 90 days. The results showed that the samples cured in the carbonation chamber presented higher compressive strength values than the ones cured in the humidity and temperature-controlled chamber, due to the fact that lime mortars increase their strength with the carbonation of the calcium hydroxide that exists in the lime. Likewise, when adding metakaolin to the lime mortars cured in the humidity and temperature-controlled chamber, the values of compressive strength were close to those of the mortars with lime only, that were cured in the carbonation chamber. From the results of the research, it is notable that the use of pozzolans in lime mortars improves the short-term compressive strength, which is attractive for the rehabilitation of heritage buildings since in short periods of time it manages to match the strengths that lime mortars acquire over time.