Influence of lime type and curing conditions on lime and lime-metakaolin mortars

Durability of Building Materials and Components (Vasco Peixoto de de Freitas, J.M.P.Q. Delgado, eds.), Building Pathology and Rehabilitation, vol. 3, VIII, 105-126. ISBN: 978-3-642-37474-6 (Print) 978-3-642-37475-3 (Online). Springer-Verlag Berlin Heidelberg. DOI: 10.1007/978-3-642-37475-3_5

Air-lime mortars with or without pozzolanic components were largely used in the past. Due to natural or accidental degradation it is often necessary the application of repair mortars, durable and compatible with the masonries of histor-ic buildings. Within this context and associating the improvement of mortars char-acteristics to the necessity of sustainable construction practices, mortars formulat-ed with limes and the addition of pozzolans have been studied. Each type of mortar presents its specificities. In pure lime mortars the setting oc-curs by carbonation and in lime-metakaolin mortars it occurs both by carbonation and hydration. A crucial question in order to optimize the characteristics of the mortars (and its applicability) is related with the curing conditions, which potenti-ate differently the reaction and consumption of the calcium hydroxide. This article describes an experimental campaign with different pure air lime mor-tars and lime-metakaolin mortars, cured under different conditions of relative hu-midity and CO2 content. Properties of the mortars, mainly in terms of mechanical behaviour and open porosity, capillary water absorption, drying capacity and re-sistance to chlorides contamination, are obtained, compared and discussed. The benefits in some properties revealed by the different mortars are correlated with the laboratorial curing conditions and with in situ application possibilities.