The Influence of Fibre Content on the Performance of Steel Fibre Refractory Concrete

Steel fibres are commonly used in the refractory industry to reinforce high temperature concretes. Little information is available on the effect of fibre content on refractory performance and in particular resistance to thermal shock. This study has examined the influence of fibre content of stainless steel melt extract fibres on the performance of a proprietary 1400 °C medium duty calcium aluminate bonded castable. Three different fibre lengths of 25, 35 and 50 mm were used in amounts of 2, 4, 5, 6 and 8 % by weight of dry material. In total fifteen mixes were investigated. Beam specimens were cyclically heated and cooled on one face in a specially designed spalling furnace to condition them in a simulated service environment. The effect of fibre content on first-crack flexural strength, ultimate flexural strength and toughness index is presented and discussed in this paper. The results show that stainless steel melt extract fibres can improve toughness and flexural strength as fibre content increases, and transform the conventional refractory from brittle material to a tough and tenacious composite. Journal of Civil Engineering Research and Practice Vol.1(1) 2004: 13-2