Steel fibre reinforcing effects on engineering properties of cement-less concretes with AAS

This study experimentally investigated mechanical and impact performances of an alkali-activated slag (AAS) concrete reinforced with hooked-end steel fibres. The compressive, flexural and impact behaviour of AAS concrete with different volume fractions (0·0%, 0·5%, 1·0%, 1·5% and 2·0%) of steel fibre were evaluated. To examine the impact resistance of steel fibre reinforced AAS concrete, a total of 20 panel specimens (200 mm wide, 200 mm long and with a constant thickness of 50 mm) were fabricated and subjected to spherical projectile impact at velocities ranging from 150 m/s to 300 m/s measured by an electro-optical device. Projectiles of diameter 20 mm and mass 38 g were accelerated using a laboratory gas gun, and the impact resistance of the AAS concrete panels was assessed from their resistance to projectile impact in terms of average crater diameter, penetration depth and average scabbing diameter after impact testing. The main findings indicate that the addition of hooked-end steel fibres to AAS concrete improves mechanical properties such as compressive and flexural strength and impact performance. These results indicate that this new cement-less concrete may be an optimal alternative to conventional ordinary Portland cement concrete for various applications in the construction industry.