“Bianco di Asiago” limestone pavement – Degradation and alteration study

Pavement tiles made of a micritic limestone were set on a residence building and shortly after its application signs of degradation were detected (efflorescences) on the tile surface. The limestone contains irregular patterns due to rock cutting across stylolites. These decorative features represent ideal roads for fluid circulation through the rock where reactions between minerals and fluids (essentially water from the mortar) occurred. Rock analyses obtained from microscopic petrography, SEM, EDS and XRD emphasize the high calcite content of the rock and the variable composition and porosity of the stylolitic zones. Results show the importance to acknowledge the rock structure before setting these natural products as construction materials. In the present work, the need for surface treatments was found important to avoid water arising by capillarity from the pavement substrate, and hence contribute to avoid the rock weakness.