The growing demand for automatically placed refractory castables, such as pumpable and shotcrete, is centered on the knowledge of each molding technique characteristics followed by the understanding of the rheological nature of these materials. For shotcrete castables, the evaluation of the additives (flocculants, set accelerators, etc.) employed to enhance materials cohesion and adhesion on the applied surface, thus reducing rebound losses, is also important. However, the procedures conventionally adopted to evaluate the influence of these additives, which are based on castables consistency after setting analysis, do not properly simulate the shotcrete process. Therefore, in the present work, a new experimental technique, based on castable rheometry, was developed to analyze commercial additives and others with theoretical potential for shotcrete. The results confirmed the benefits of the developed technique and identified new additives with superior efficiency for shotcrete application.
castable; additives; shotcrete; rheometer; refractories
