New insight into the equivalent concrete mortar approach for self-consolidating concrete

The concrete equivalent mortar (CEM) approach consists in replacing the coarse aggregates (CA) of concrete by a mass of sand to provide an equivalent specific surface area at mortar scale. Such approach can be used to reduce time and cost needed to design self-consolidating concrete (SCC). The approach is extended with less success to evaluate rheological properties of SCC using those of the corresponding CEM. The limitation of the approach is mainly due to the fact that the surface area of aggregates is the only used criterion. The objective of this investigation is to evaluate the applicability of the original CEM approach and establish correlations between rheological properties of CEM and SCC. Various SCC mixtures were proportioned with different CAs and binder contents varying from 27 to 36% and 300 to 500 kg/m(3), respectively. The obtained test results show that the excess paste theory is a key factor in studying relationship between CEM and SCC. Good correlations between flow properties of CEM and SCC are obtained when the excess paste thickness and CA content are taken into account.