An end of waste alternative for volcanic ash: a resource in the manufacture of ceramic tiles

The paper deals with an experimental study aimed at assessing the possible re-use of volcanic ash as temper in the manufacture of ceramic tiles. Needing to find end of waste alternatives for this material arises from the awareness that the fall-out of large quantities of ash in active volcanic areas causes many inconveniences to communities living and working in close proximity to the volcano. Volcanic ashes recently erupted by Mount Etna volcano have been here chosen as case study for these purposes. Ceramic test-tiles were manufactured by mixing volcanic ash with a calcareous clayey raw material, by using specific proportions of clay/temper. In order to assess the quality of the products, the tiles underwent several physical–mechanical tests including: a) water absorption; b) bending resistance; c) impact resistance; d) resistance to deep abrasion; e) thermal shock resistance; f) frost resistance; and g) accelerated aging test by salt crystallization. The obtained results have been then compared with those of a reference product manufactured by using another volcanic material known as azolo (i.e., ground basalt) for a long time on the market. Our data demonstrate how basaltic ash recovering through this methodological approach is highly promising in the sector of building materials.