Effect of the Fibre Geometry on the Flexural Properties of Reinforced Steel Fibre Refractory Concrete

Steel fibres are commonly used in refractory industry to reinforce high temperature concretes. Little information is available on the effect of fibre geometry on the refractory concrete and in particular to thermal shock. Eleven different melt extract fibre geometries were investigated with fibre lengths of 10 mm, 25 mm and 50 mm and aspect ratios varying from 14 to 108. Beam specimens made from a proprietary dense hydraulically bonded castable, reinforced with 5% by weight of steel fibre, were cyclically heated and colled on one face in a specially designed spalling furnace to condition them in a simulated service environment Flexural tests were conducted at service and room temperature to obtain toughness indices. The relationship between fibre geometry and toughness indices is discussed.