Formulation and rheology of eco-self-compacting concrete (Eco-SCC)

This article presents the results of an experimental study on the rheology of eco-SCC, formulated on the basis of the modified Chinese method and on the new standard EN206/CN. The studied ecological concretes consist of Portland pozzolana cement, containing large amounts of limestone filler or natural pozzolana, which can replace cement up to 50%. In addition, the compactness of the granular mixture is optimized; therefore, the total amount of the incorporated binder is further reduced in the body of concrete. The study of the rheological behavior of these fluid concretes was carried out in the laboratory, using a coaxial vane-type rheometer. The results showed that both rheological models, i.e. modified Bingham and Herschel-Bulkley, describe satisfactorily the shear-thinning character of the formulations tested. However, the rheological parameters obtained with the modified Bingham model seem to have better correlations with the measurements of the slump test. These same results also indicated that replacing 30% of cement by one of the additions selected for our study, resulted in mixtures with yield stress and plastic viscosities that are within the validity range of SCC. This allowed reducing CO2 emissions by about 40% for each cubic meter of concrete produced.