Lime mortar with natural pozzolana: historical issues and mechanical behavior

The paper deals with the investigation of the mechanical behavior of lime mortar enriched with natural pozzolana, widely used in historical masonry. The study aims to investigate the mechanical behavior of natural pozzolana lime mortars, reproduced in laboratory by using different mix designs, as reported in historical Italian architectural treatises, and natural pozzolana coming from Viterbo (Italy). To this purpose, the works of many among the most important authors from the Ist century b.C. up to 1864 have been analyzed, in order to collect historical mix designs of pozzolana lime mortars. A set of different mortars was prepared and tested with respect to the new European Standards (EN 459, 2002). Flexural and compression tests were performed following EN 1015-11 (2007). Mechanical tests were performed after 28 days and 60 days of curing. Penetration tests, not included in European Standards but very suitable for practical applications, was also performed.