The use of Egyptian volcanic glass powder as a potential source for improving the properties of alkali-activated fly ash cement

In this article, for the first time, the potential use of Egyptian volcanic glass powder (VGP) has emerged as an intriguing option. The intriguing potential advantages of incorporating VGP into alkali-activated fly ash (AAFA) cement were explored. The volcanic glass (VG) was brought from the Egyptian eastern desert quarry in the form of lumps and fragments. To utilize it effectively, the VG was crushed and ground before being mixed with fly ash (FA). Various proportions of VGP ranging from 10% to 70% were blended with FA as a partial substitution. Both plain FA and those blended with VGP were then activated using an alkaline activator, resulting in the creation of alkali-activated cement. An investigation was conducted to assess the effect of various ratios of VGP on the flowability, compressive strength up to 90 days, resistance of drying/wetting cycles, crystalline phases, hydration products, and microstructures of AAFA cement. The results confirmed a positive effect of AAFA properties with including VGP. The obtained blended cement can be used in several potential applications such as in roadways, bridges and tunnels, facades and cladding, indoor and outdoor floorings, as well as aerospace and defense industries due to its high durability to resist the degradation caused by wetting/drying cycles. [Display omitted] •VGP showed a noncrystalline phase and contained a high ratio of silica and alumina.•VGP increased the flowability and compressive strength of AAFA cement.•VGP can mitigate the strength degradation in the matrix caused by repeated cycles.•Including VGP in the AAFA cement produced a more compact microstructure.