Modification of Cement Stiffening Time

The stiffening time of cement is a feature whose potential can be better exploited at function of each specific use of concrete. The possibility of control of this feature is useful, as much to get a better concrete performance at function of the each work peculiarities, as to correct behaviour distortions regarding to usual or expected. The velocity of cement stiffening can be varied through chemical admixtures or, then, by the alteration of own cement composition; is this last alternative that will be considerate in the present paper. Are showed the results of cements prepared with laboratory and industrial clinkers whose composition change, involving the fluorine presence, implicate at essential alterations in the cement performance.