پوشش ملاتهای گچ باستان از صومعه های متعدد و کاخ های اسلامی و سبک گوتیک در پالما د مایورکا (اسپانیا). خصوصیات تحلیلی

Analysis of historic mortars including Islamic, Gothic and later ones taken from palaces, convents and mansions in Palma de Mallorca has been carried out. Scanning electron microscopy (SEM) coupled to energy dispersive X-ray spectrometer (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques were used to characterise the morphology and analytical composition of the samples analysed. Generally, covering plaster mortars presented a low percentage of small size aggregate. The reported results show that mixed and lime mortars have been used, thus, the establishment of a relationship between the type of mortar employed and its age is not feasible. In the painted mortars, polychromy has also been studied. The most common pigments to be found are natural earths.

Most of the covering plaster mortars analysed belong to the lime mortar group. Among the mixed gypsum–lime mortars, the proportions of calcite–gypsum found are in good agreement with those stated in the ancient treatises. Comparison of analytical composition of 11th century with 15th century lime mortars shows no differences. It was found that rich-gypsum mortars were much harder and compact than those of calcite. Generally speaking, microcrystalline appearance may be related to the physical and mechanical properties of the mortar. The analytical composition and morphology displayed by the mortar according to the SEM observations may be related to the working methodology used in the building trade. It must be pointed out the high-quality manufacture of the covering plasters analysed. The choice of raw materials in the manufacture of mortars contributes to a large extent to relevant properties such as hardness and cohesion of the final product.