The use of supplementary cementitious materials (SCMs) in formulations of concrete is expanding worldwide.However, this practice changes the hardened state properties, because the compositions are formulated using lower binder content, and the effects on the performance in use and durability are still not completely understood.Blast furnace slag, limestone filler, fly ash, silica fume, and others, are some example of SCMs used today;their interactions with Portland cement are widely discussed in the literature.Iron-rich materials, such as bauxite residue (BR), do not have its interaction with cement very well understood, mainly during the transition from fluid-to-solid behavior.This residue is known to have negligible impact on the hardened properties, but the chemical reaction and the rheological properties are modified.Hence, our aim is monitoring the fluid-to-solid transition of compositions of different Portland cements blended with bauxite residue.Isothermal calorimetry,oscillatory rheometry and X-ray diffraction were the methods used.It was thus possible to evaluate the physico-chemical contribution and the hydrated compounds formed during hardening.A delay in the chemical reaction in function of the use of BR was observed, but the changes were more influenced by the cement composition.Formation of hydrogen carbonate of sodium hydrated and sodium silicoaluminate hydrated was observed, negligibly impact on the formation of hydrated calcium ferrite phases, and increase in the formation of hydrated silicate and aluminate phases were observed.The rheological properties changed and the yield stress,monitored in function of time, was higher in suspensions with BR than in the reference ones.