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

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 resistanc

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

Efflorescence is one of the limitations of the widespread use of geopolymers. This problem is caused by excess unreacted sodium oxide remaining inside materials. Unreacted sodium oxide creates white efflorescence on the surface of the produced material in the form of sodium carbonate heptahydrate Na2CO3∙ 7H2O. It decreases not only the aesthetic value of the final products, but also the mechanical properties of the material. The aim of this article is to analyse the influence of the curing method on the appearance of efflorescence on geopolymer composites reinforced by short basalt, especially on mechanical properties. Class F fly ash from the ‘Skawina’ coal-fired power plant (located in Skawina, Lesser Poland, Poland) was used as raw material for the geopolymerization process. The article compares two methods of curing: typical laboratory conditions (in the air) and samples submerged in water. Three series of fly ash-based geopolymer were cast: basalt fibres were added as 1% and 2% by weight of fly ash and one control series without any fibres. The investigation was performed using visual analysis, including microstructure investigation, and the testing of mechanical properties (compressive strength at ambient temperature) after 28 days

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

Efflorescence is one of the limitations of the widespread use of geopolymers. This problem is caused by excess unreacted sodium oxide remaining inside materials. Unreacted sodium oxide creates white efflorescence on the surface of the produced material in the form of sodium carbonate heptahydrate Na2CO3∙ 7H2O. It decreases not only the aesthetic value of the final products, but also the mechanical properties of the material. The aim of this article is to analyse the influence of the curing method on the appearance of efflorescence on geopolymer composites reinforced by short basalt, especially on mechanical properties. Class F fly ash from the ‘Skawina’ coal-fired power plant (located in Skawina, Lesser Poland, Poland) was used as raw material for the geopolymerization process. The article compares two methods of curing: typical laboratory conditions (in the air) and samples submerged in water. Three series of fly ash-based geopolymer were cast: basalt fibres were added as 1% and 2% by weight of fly ash and one control series without any fibres. The investigation was performed using visual analysis, including microstructure investigation, and the testing of mechanical properties (compressive strength at ambient temperature) after 28 days