TY - JOUR AU - Fernández-Jiménez, A. AU - Puertas, F. PY - 1997/06/30 Y2 - 2024/03/28 TI - Influence of the activator concentration on the kinetics of the alkaline activation process of a blastfurnace slag JF - Materiales de Construcción JA - Mater. constr. VL - 47 IS - 246 SE - Research Articles DO - 10.3989/mc.1997.v47.i246.505 UR - https://materconstrucc.revistas.csic.es/index.php/materconstrucc/article/view/505 SP - 31-42 AB - The influence of activator solution concentration on hydration kinetics of an alkaline activated blast furnace slag has been studied. The alkaline activator used was a mix of waterglass (Na<sub>2</sub>SiO<sub>3</sub>∙nH<sub>2</sub>O) and NaOH solution (of variable concentration). Final activator concentrations were 3,4 and 5 % Na<sub>2</sub>O wt. with respect to the slag total weight.Degree of reaction (α) was determined from hydration heat values obtained through isothermal conduction calorimetry. From the results obtained it is deduced that a treshold value of 4 % Na<sub>2</sub>O wt. exists. For those concentrations and at test temperatures (except for 25ºC and 3 % Na<sub>2</sub>O wt.), the mechanism controlling hydration reaction for a values higher than 0.5, is a diffusion process. This process is described by .Jander equation [D<sub>3</sub>=(1-(1-α)<sup>1/3</sup>)<sup>2</sup>=(k/r<sup>2</sup>)t=0,0426(t/t<sub>0,5</sub>]. The activation energy obtained for that process is of approximately 50-58 Kj/mol. ER -