Characterization of Earth, Lime, and Gypsum Mortars in the Constructions of the 16th, 17th, and 18th Centuries

The historical mortars of three ecclesiastical assets of the Colonial Quito were analyzed, which by 1978 was declared as heritage by UNESCO. The emblematic works of Jesuits, Dominicans, and Franciscans, built between the 16th to 18th centuries have multiple constructive stages and interventions of which there is no technical record because of the historical and present space of worship, living and religious museum of Quito. The objective of the lining mortars characterization is to provide the clear information of the composition of the analyzed samples for better understand the constructive chronology of the churches and to determine which earth, lime, gypsum, etc. mortar was used frequently according to the epoch and religious order. A total of 48 samples of lining mortars of the interior and exterior of the temples were examined, with the protocols and norms on non-destructive essays suggested by the research team. The analysis comprising stereomicroscopy studies that were complemented with mineral characterization and quantitative analysis by X-ray diffraction, as well as polarized light optical microscopy and scanning electron microscopy with microanalysis of the samples, among others. The results in the laboratory allowed us to demonstrate the existence of earth mortars, lime and gypsum bastards, and gypsum mortars with carbonate aggregate, those elements have volcanic and metamorphic volcanic mineralogical composition, this allowed us to date into the constructive stages registered in the church. The results in the laboratory allowed us to demonstrate the existence of earth mortars, lime and gypsum bastards, and gypsum mortars with carbonate aggregate, those elements have volcanic and metamorphic volcanic mineralogical composition, this allowed us to date into the constructive stages registered in the church