Dryout temperature–vapor pressure profile of polymeric fiber containing refractory castables

Different types of polymeric fibers are added to refractory castablesʹ formulations as drying additives to make dewatering processes easier and reduce the risks of explosive spalling of these low permeability materials. Many works describe how these fibers control the permeability increase in castables before and after their melting-decomposition. The water vapor pressure profile developed inside the structure and how it is modified by the fiber presence has not yet been explored systemically. In the present paper, thin K-type thermocouples were inserted (at different depths) in polymeric fibers (olefin copolymer, polypropylene and aramidic ones) containing castable samples. Their temperature profile and mass loss were recorded during the first heat-up. After combining internal heating and mass loss rate, vapor pressure levels calculated using Antoineʹs equation, hot air permeametry (HAP) and work of fracture (γWOF) results, novel insights into the mechanisms by which polymeric fibers avoid explosive spalling during castables dewatering were attained.