ABSTRACT
During recent years, many variations have been made in the formulations of hydraulic cements and some of these variations will affect the early age behaviour of concrete. In addition, fly ash and ground granulated blast-furnace slags and silica fume have been combined with Portland cements at the concrete mixer and this practice, too, affects the early age performance of concrete. The importance of these changes is not always obvious. One such effect relates to the setting and early strength gain of concrete. Such delays can be unwelcome on site if tasks can no longer be completed during a working shift.
