Condições de mistura e a permeabilidade de concretos refratários contendo fibras poliméricas

Polymeric fibers have been added to refractory castables to improve their permeability and reduce the risks of spalling during the drying step. Nevertheless, the fiber addition inhibits a homogeneous mixture and also diminishes the castable workability. Previous work of the same authors has shown that the gain in permeability is related to the final medium length of fibers and the processing conditions. The aim of this work is to establish the relations between the permeability increase and the processing conditions of refractory castables containing polymeric fibers with different lengths. The rheological behavior during mixing was analyzed using a castable rheometer. Two processing conditions were investigated: fibers addition to the dry material and addition of fibers after mixing. The permeability analysis was carried out using Forchheimer's equation. The relationships among mixing energy, permeability and final medium lengths of fibers were established.