Thermomechanical evaluation of self-flowing refractory castables with and without the addition of aluminate cement

Abstract

Much has been discussed about the advantages regarding the thermomechanical performance of self-flow refractory castables (SFRC), with very little or no addition of calcium aluminate cement (CAC) when compared to conventional composites with cement. Previous works demonstrated that a 100% alumina SFRC with optimized particle size distribution simultaneously results in high-flowability fresh paste and high mechanical strength.In this work, the thermomechanical behaviour of zero-cement ceramic matrix is compared to that of the equivalent composite with 1% CAC content.The results show that the differences in performance can be related to differences in hydration mechanisms, namely the formation sequence of calcium aluminate hydrates, which results in increased open porosity. With lower dried strength, the all-alumina castable presents lower porosity, higher mechanical strength and uncompromised thermal shock resistance, being a valuable option when fast drying or rough green handling can be avoided.