Determination of optimal burning temperature ranges for production of natural hydraulic limes

There has been an increasing interest in the reproduction of natural hydraulic limes, as they are considered an appropriate material for conservation and restoration of historic buildings. This study assessed the influence of different calcination temperatures (850–1200 °C) on the mineralogical composition and the reactivity of quicklime, as well as the setting time and the mechanical performance of mortar specimens. The limestone was acquired from a single quarry and contained 8.7% SiO2, 45% CaO. The results of XRPD and slaking reactivity of the produced quicklime confirmed a clear dependency on the calcination temperature. The performance properties of mortars made with the produced lime did not demonstrate a clear relation to the calcination temperature. The experiment confirmed that calcination temperatures from 850 to 1200 °C can be used to produce natural hydraulic lime from the selected limestone. The optimal calcination temperature range from 1000 to 1100 °C is recommended.