Mechanical Properties of Basalt Fiber Reinforced Fly Ash-Based Geopolymer Composites

Abstract

This article analyses the influence of a short basalt fibre admixture on the mechanical properties of geopolymers, especially compressive strength. This preliminary research is the first step towards the development of a composite for fire resistant applications in civil engineering. This study investigates the behaviour of a fly ash based geopolymer containing basalt fibres. Fly ash from the coal power plant ‘Skawina’ (located in: Skawina, Lesser Poland, Poland) was used as the raw material. The chemical composition of this fly ash is typical for class F. Three series of fly ash based geopolymers were cast. In the first, short basalt fibres were added as 1% by weight of fly ash, in the second short basalt fibres were added as 2% by weight of fly ash and the third functioned as a control series without any fibres. Each series of samples were tested on compressive strength after 28, 14 and 7 days, and specimen density was determined. Additionally, microstructural analysis was carried out after 28 days. The results show that the addition of basalt fibres can improve the mechanical properties of geopolymer composites.
 Keywords: geopolymer, basalt fibre, composites, fire resistance

The impact of the curing process on the efflorescence and mechanical properties of basalt fibre reinforced fly ash-based geopolymer composites

“…This behaviour was the same for all curing methods. The change of the behaviour is coherent with the research reported in the literature [29][30][31][32].…”

“…Preliminary observations confirm the regular distribution and coherency of fibres and the geopolymer matrix [29]. The SEM investigations enabled familiarisation with the overall structure of the composites and the role of fibres.…”

“…The research also allows indirect observation of changes in the behaviours of samples. The plain basic samples were broken in brittle way, whereas for the samples with fibres, the mechanism of breaking was more ductile [29]. This behaviour was the same for all curing methods.…”

“…The compressive strength changes should also depend upon the fibre content. The literature shows that the results for reinforced samples are usually better [29][30][31][32]. However, lower values for compressive strength for the samples with fibres have been previously reported in the literature [29,33].…”

“…4a, the fibres that are actively involved in strength transmission are visible. The cracking is limited by the presence of fibres [29]. Moreover, some fibres probably partly dissolved during geopolymerisation.…”