A study of the ancient mortars in the north tower of Pamplona's San Cernin church

Different ancient mortar samples of Pamplona's San Cernin church have been analyzed to characterize their binder and aggregate fractions. A complete characterization has been carried out including chemical (rapid approximate analysis, soluble salts and trace elements, using traditional chemical procedures, ionic chromatography and spectrophotometry techniques), mineralogical–petrographic, (structural characterization and X-ray diffraction) and thermal studies (simultaneous differential thermal and thermogravimetric analysis). These studies have established that a type of lime mortar with silica aggregate was employed in the building of the tower. Three different classes of this type of mortar and their approximate original composition have been determined. Recommendations about the employment of new materials in a possible restoration are given