Effect of different lengths and dosages of recycled glass fibres on the fresh and hardened properties of SCC

An experimental and analytical investigation was carried out to examine the feasibility of using recycled glass fibres in self-compacting concrete (SCC). Different fibre volume fractions (0·5, 1, 1·5 and 2%) and different fibre lengths (10, 20 and 30 mm) were used to assess both the fresh and hardened properties of fibre-reinforced SCCs. The fresh properties were assessed in terms of flowability and viscosity, while the hardened properties of 130 specimens were characterised in terms of ultrasonic pulse velocity, compressive strength, flexural strength and impact resistance. The specimens were thus tested experimentally to characterise their mechanical properties and impact resistance. Backscattered electron images and elemental maps were used to identify the crystalline structure of the cementitious matrix, and energy-dispersive X-ray spectroscopy was employed to determine the qualitative or semi-quantitative chemical compositions of the cementitious mix composition. The surface topography and morphology of the embedded glass fibres in the matrix were also evaluated. The results showed that increasing the volume fraction and length of the recycled glass fibres improved both mechanical properties and impact resistance. Moreover, it was found that the mechanical properties and impact resistance could be linearly correlated to the recycled glass fibre volume fraction.