Impact resistance of high-strength fibre-reinforced concrete

Abstract

The current paper presents results from a laboratory experimental study on the resistance of concrete to simulated impact loading of fragments. The impact of fragments was simulated by the impact of ogive-nosed projectiles with a diameter of 12·6 mm and a mass of 15 g travelling at velocities from ∼610 to 710 m/s. The concrete tested had 28 day compressive strengths from 45 to 170 MPa. Effects of the content, type and length of fibres in concrete and the compressive and flexural tensile strength of the concrete on the impact resistance are evaluated and discussed. The results indicate that the incorporation of a small amount of fibres can reduce the crater diameter effectively as the fibres are able to bridge cracks and to hold concrete together. However, in order to reduce the penetration depth, reduced water-to-cement ratio and increased strength of the concrete matrix are required. A strong aggregate with bigger sizes seem to be beneficial to improve the impact resistance so long as the workability is satisfactory and the aggregate sizes meet requirements based on the size of structural members and the spacing between reinforcing bars and spacing between reinforcing bar and formwork.