Etna volcanic ash as new sustainable supplementary cementitious material

The use of supplementary cementitious materials (SCMs) is one of the fundamental pillars the transition towards sustainable binders, and the seek for new alternative SCMs is becoming more and more important to front, on one hand, the increased request, and the expected future shortage of some existing SCMs, such as blast furnace and steel slag, on the other. In this work the use of volcanic ash as a pozzolanic constituent in the manufacture of a type IV mixed cement has been explored. Thousands of tons of ash are erupted for each Strombolian event from the volcano Etna (Italy) . The periodicity and magnitude of the events is variable but very often impressive. In the year 2021 alone, 51 significant paroxysmal events occurred. The enormous quantities of material removed from urbanized areas constitute a valuable resource that can be reused instead of being disposed of as waste. The experimental results of the tests carried out for the physical, mechanical and chemical characterization of the new mixed cement showed that the volcanic material meets the requirements dictated by the standard EN 196-5 to assess pozzolanic properties, and can be effectively used in the production of commercial pozzolanic cements as a partial, or even total replacement for the natural pozzolans. These findings are fundamental to encourage the start-up of a production chain aimed at recycling the waste eruptive material of volcanoes that insist on urbanized areas. Moreover, a review of the regulative framework concerning test methods assessing the pozzolanicity of volcanic material is given.