everal publications have reported the benefits of adding polymeric fiber ... as presenting an exponential dependence on the volumetric amount of fibers ... refractory castable formulation is used as well as mixing, curing, drying and ... cement (CA 14, Almatis Inc., Leetsdale, Pa.). .... after thermal treatment of castables con-.
Polymeric Fiber Geometry Affects Refractory Castable Permeability Selected values of polymeric fiber length and diameter maximize the permeability level of castable refractories, which decreases destructive spalling.
R. Salomão, A.M. Zambon and V.C. Pandolfelli Federal University of São Carlos, São Carlos, S.P., Brazil
everal publications have reported the benefits of adding polymeric fiber to aid the drying step of refractory castables.1–3 Fibers have been described as permeability magnifier additives that allow an easier release of the pressurized water vapor entrapped when castables undergo a heating process. This mechanism can greatly decrease the risk of explosive spalling and the resulting idle time of equipment lined with refractory castables.3
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The permeability increase is associated with the channels generated by the fibers after their melting and decomposition.3–7 The chemical composition of the fibers (and, consequently, their thermal behavior) is an important factor when setting the permeability increase temperature. High-temperature-resistant fibers (such as polyester and aramidic fibers) generate permeability increases at temperatures >200°C (235 and 400°C, respectively), whereas more susceptible fibers (such as polypropylene) can generate permeability increases at temperatures
