Analysis of pozzolanic mortars for restoration

Historical centers, clusters of masonry buildings form the major part of the world architectural heritage, which has been mainly built in seismic areas. The last earthquakes have put in evidence its vulnerability and the need of assessment. The performance-based demands of recent seismic codes developed for Cultural Heritage require a deep knowledge of mechanical properties of structural materials, and among them the lime mortars play a key role. The drawing of significant samples of structural mortars from existing buildings is not always a simple task, so that the laboratory reproduction of ancient mortars is the best way to obtain reference values for restoration materials fulfilling code requirements. Based on an historical study of compositions, this paper presents an analysis of strength properties of traditional mortars, composed by lime and pozzolan as an aggregate. The laboratory tests, performed by the authors on different types of pozzolanic lime mortars, are compared to those present in literature and discussed.