A multi-analytical approach was used to study the pictorial layers of a set of 17th century historic glazed tiles (azulejos) of Portuguese manufacture. The pictorial layer was studied by-EDXRF,-Raman, SEM-EDS and OM. Although the established palette comprises few pigments, it was found that the tiles were enhanced by the use of pigment mixtures, which were identified by-Raman and-EDXRF. As expected, the blue colour derives from cobalt oxide, purple from manganese oxide and emerald-green from copper oxide. Regarding the yellow pigment,-Raman results show it is consistent with the composition of a ternary oxide, whereas-EDXRF shows a high intensity of Zn in this colour, indicating a composition close to a Pb-Sb-Zn ternary oxide. Some compounds from the original ores were also indentified: in two very dark blue samples, cobalt and nickel olivines (␣-Co 2 SiO 4 , ␣-Ni 2 SiO 4), and in a dark brown sample, braunite (a manganese silicate).

This work evaluates the influence of the binder:aggregate ratio in respect to mineralogical and mechanical properties of air lime-metakaolin mortars.Mineralogical analysis showed that binder:aggregate ratios modifies the extent of carbonation and pozzolanic reactions with curing. The pozzolanic reaction occurs mostly at lower curing times (28 days), while, at higher curing ages, carbonation reaction is mostly dominant. The exceptions are mortars with 1:1 (air:lime) volumetric ratio with 30% and 50% MK in which the pozzolanic reaction is still dominant.For conservation purposes, the mechanical tests demonstrated that 1:2 and 1:3 mortar volumetric ratios were considered adequate proportions since 1:1 was considered a "strong" ratio, as it can induce tensions and mortar shrinkage that can damage historic masonries. Keywords

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Grilo, J.; Santos Silva, A.; Faria, P.; Gameiro, A.; Veiga, R.; Velosa, A. Mechanical and mineralogical properties of natural hydraulic lime-metakaolin mortars in different curing conditions. Construction and Building Materials, v. 51, p. 287-294, 2014. January 2014 1 Tests were conducted at different curing ages, using compressive and flexural strength tests and thermogravimetric and X-ray diffraction techniques.NHL mortars cured at high humidity levels in natural and artificial environments present interesting results and some could be used in old masonries repair.The incorporation of MK improves the NHL mortars strength, being this increase mostly associated to the pozzolanic reaction. KeywordsHydraulic mortars; NHL3.5; metakaolin; curing conditions; characterization; XRD; TG-DTA;Grilo, J.; Santos Silva, A.; Faria, P.; Gameiro, A.; Veiga, R.; Velosa, A. Mechanical and mineralogical properties of natural hydraulic lime-metakaolin mortars in different curing conditions. Construction and Building Materials, v. 51, p. 287-294, 2014. January 2014 2 IntroductionEarly civilizations, namely the Greeks and Romans, produced limes to employ in mortars for construction. The durability of these mortars is recognized worldwide, even in buildings exposed to water and is mainly attributed to the use of natural earth- The use of hydraulic lime, that also goes back to antiquity with the use of limes with various levels of hydraulicity, has been revived in the past few years, especially when the conservation of historical buildings is pursued. In particular, the natural Grilo, J.; Santos Silva, A.; Faria, P.; Gameiro, A.; Veiga, R.; Velosa, A. Mechanical and mineralogical properties of natural hydraulic lime-metakaolin mortars in different curing conditions. Construction and Building Materials, v. 51, p. 287-294, 2014. January 2014 3 hydraulic limes seem to have the possibility to be an adequate choice due to their improved compatibility with old masonry, by having low shrinkage, resistance to salt and frost damage, in comparison with PC or other hydraulic lime mortars, as well as higher deformability and water vapour permeability [5,9,12].NHL are obtained by calcining mixtures of clayish or siliceous limestones at temperatures below the clinkering point, before being reduced to a powder by adding controlled amounts of water. A fundamental characteristic of these lime mortars is the fact that they have two hardening phases: a hydraulic phase, based on its hydration, resulting in the formation of calcium and calcium-aluminum silicate hydrates, and another developed during the CO 2 contact, and designated as carbonation [11,13,14]. Pozzolans are composed by siliceous and silico-aluminous substances, which when hydrated do not harden with water; however, when they are powdered and in presence of calcium hydroxide they react to form new compounds, such as silicates and calcium aluminate hydrates, with hydraulic properties [1,17,18].Besides the influence of the addition of pozzolanic materials the mortars' curing conditions...

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