The dispersion of refractory castables matrix presents a great influence on their rheological behavior, which defines the most appropriate methods for placing these materials. The growing demand for automatically transported refractory castables has promoted the use of pumpable castables, usually specified as self flow compositions. Nevertheless, castables with higher fluidity present longer workability, leading to extended demoulding times. Because the strength development is intimately linked to the hydration process of calcium aluminate cement or hydratable alumina, it needs to be controlled in order to reach the minimum time for demoulding, contributing to reducing overall costs. The control of cement hydration depends on the knowledge of the variables that determine the kinetics of the involved reactions. In this context, the objective of this work was to evaluate the influence of the sources of the hydraulic binder, the temperature and the presence of matrix or inorganic additives on the hydration process, carried out through temperature measurements and oscillatory rheological tests, as a function of the time.
hydration; hydratable alumina; calcium aluminate cement
