Influence of secondary carbon fiber on the mechanical behaviour and microstructure of alkali-activated granulated blast furnace slag-based composites

Abstract

This study aimed to investigate the mechanical behaviour and microstructure of an environmentally friendly fibre-reinforce alkali-activated composites. The composites were obtained from alkali-activated granulated blast furnace slag reinforced with chopped secondary carbon fibres (SCFs) coming from the aircraft industry carbon fiber reinforced plastics waste. Three types of surfactants and two concentrations of SCFs were investigated. The compressive and bending strengths were measured to evaluate the mechanical behaviour of specimens. Moreover, the polycondensation products, pore structure, and microscopic morphology of the composites were analyzed using X-ray diffraction (XRD), method of standard contact porosimetry (MSCP), and scanning electron microscopy (SEM). It was found that tetraethylammonium bromide and a superplasticizer agent Glenium-51® increase compressive strength for reference granulated blast furnace slag-based alkali-activated matrix approximately by 60 % and lead to lower open porosity from 16 to 5 %. The experimental results showed that the incorporation of 0.7 vol. % SCFs had an optimal influence on mechanical behaviour and microstructure of composite. Based on the test results, it can be clearly said that using of Glenium-51® is improving the compressive strength of slag based alkali-activated composites reinforced SCFs.