Synergistic performance of steel-brass hybrid fibres on the concrete fracture properties

The main objective of the present study was to examine the possible improvements on the fracture properties of concrete containing two different fibre types (steel-brass hybrid fibres). To study the fracture properties and load resistance at various scales, discrete short brass fibres and double-hooked steel fibres were added in concrete. Different types of concrete mixtures were prepared and tested which contained varying proportions of steel and brass fibres upto 0.4% volume fraction. The effects of different hybrid fibre combinations at low and high dosages were investigated in compression and flexural resistance. Test results indicated that the different hybrid fibre combinations played a significant crack arresting properties depending upon the fibre properties (size and fibre availability). The presence of steel fibres provided post crack resistance properties whereas the shorter brass fibres delayed the crack origination resulting in significant increase in mechanical strength. The hybrid fibre concretes containing steel fibres (0.3% Vf) and brass fibres (0.2% Vf) showed a consistent increase in the ultimate stress capacity up to 7.75% (in compression) and 37.98% (in fracture strength). Microscopic studies showed the effectiveness of different hybrid fibres during crack formation and subsequent propagation at different loading stresses.