Review on the use of volcanic ashes for engineering applications

Volcanic ashes are pyroclastic materials commonly found in many regions of the world. Many deposits of volcanic ashes are unexploited, despite their potential interest for several engineering applications. The mineralogy and chemical composition of volcanic ashes depend on the type of magma from which they originate. The two common pyroclastic materials of interest for engineering applications are scoria and pumice. These pyroclastic materials are rich natural aluminosilicate geo-resources and their valorization can be of environmental and economic benefit. The current review summarizes the main interesting research outcomes on volcanic ashes in the fields of cements and concretes, geopolymers, ceramics, low grade refractory materials, lunar soil simulants and adsorbents. Factors affecting their suitability for specific applications are screened and possible areas of interest for future research suggested.