The influence of fibre pre-treatment on the mechanical properties of the geopolymer composites

This article aims to analyse the long-term influence of the pre- treatment method on mechanical properties such as the compressive strength of geopolymer composites reinforced with short natural fibres (length of around 5 mm). This paper presents the behaviour of sodium activator-synthesised fly ash geopolymer containing natural fibres at ambient temperatures. Fly ash from the Skawina coal power plant (located in: Skawina, Lesser Poland, Poland) was used as a raw material. The chemical composition of the fly ash was typical for class F. The article evaluated the methods of pre-treatment of the fibres on the mechanical properties of the geopolymer composites. It compares the plain specimens and composites with fibres pre-treated in water and alkali solutions as well as with fibres without any pre-treatment. The fibres were added at the amount of 1% by weight. The investigation was made by visual analysis and the testing of mechanical properties (compressive and flexural strength at ambient temperature) after 6 months. The achieved results do not confirm the positive influence of the fibre pre-treatment on the mechanical properties of the composites.