Mechanical properties of reactive powder concrete with ultra-short brass-coated steel fibres

The mechanical properties (compressive strength, quasi-static fracture behaviour under three-piont loading, and fracture energy) of reactive powder concrete with ultra-short brass-coated steel fibres (12, 6 and 3 mm) were investigated. Steel fibre length had a small impact on the compressive strength of reactive powder concrete. Nevertheless, the quasi-static fracture behaviour showed clearly lower load-carrying capacity after the peak load with decreasing steel fibre length, indicating the decreased toughness of reactive powder concrete with shorter steel fibres. Obtained by integrating the area under the load-deflection curve, the fracture energy sharply decreased about 50% when reducing steel fibre length from 12 to 3 mm. These results will give guidance for the fabrication and study of reactive powder concrete-metal sandwich protective structures with high ballistic performance, low weight and low fabrication cost in the future.