Refractory castables comprise a large and diverse group of materials in the family of monolithic (shapeless) refractories. Their use has grown significantly in the past 30 years. Progressing from simple mixes, refractory castables today comprise some very complex and technical formulations, finding use in a variety of very demanding and severe applications.
Refractory castables are premixed combinations of refractory aggregates, matrix components or modifiers, bonding agents, and admixtures (Fig 1). They are mixed with a liquid (usually water) at the point of installation and vibrated, poured, pumped, or pneumatically shot into place to form a refractory shape or structure that becomes rigid because of hydraulic or chemical setting. The majority of refractory castables use calcium aluminate cement as the bonding agent though in recent years other bonding agents have also been developed. All castables have refractory aggregates and matrix components which allow their use to temperatures up to 1850 deg C.