Chemical additives may be added to the castables for different purposes, as for example, to disperse matrix fine particles through electrostatic/electrosteric mechanisms (dispersants) and to control the hydration process of cement particles (retarders/accelerators). The state of dispersion of the castables matrix particles presents a direct influence in their rheological behavior, defyning the techniques that can be used for their installation. The growing demand for automatically transported refractory castables has stimulated the use of pumpable castables due to its fast and high quality placing, without losses and with reduced costs. However, in order to explore the technological advantages of this process it is necessary that the rheological behavior and setting characteristics of castables are in tune with the process. In this context, the objective of this work was simultaneously evaluate the influence of the different additives on the matrix particles dispersion and the hydration process of different hydraulic binder, through fluidity and setting time measurements of refractory castables.
hydratable alumina; calcium aluminate cement; refractory castables; fluidity; workability
