Wet shotcrete is a technique that consists on spraying the castable on a surface, affording high placing rate and efficient material packing. Wet shotcrete does not require the use of molds due to the presence of accelerating admixtures or coagulants which immediately reduce fluidity of the castable sprayed on the surface. The usual evaluation of the additive performance is based on the amount of material adhered on the surface (rebound loss). However, distinct coagulation mechanisms can affect the thermomechanical properties of the material in different ways. Studies reported that final properties of castables, such as creep flow, are related to the matrix amount. Thus, the purpose of this work was to evaluate the impact of coagulants and accelerating admixtures on the thermomechanical properties of wet shotcrete refractory castables matrix. The results show a great impact of the additives on the mechanical strength and creep of the matrix. Moreover, a new class of shotcrete additives, which promotes a better performance of the material when compared to commercially used admixtures, was identified.
refractory castable; shotcrete; additives; thermomechanical properties
