Efficient self-compacting concrete with low cement consumption

Self-compacting concretes (SCCs) must have high fluidity, cohesion and should not segregate. These characteristics of fresh concrete increase the cost of production, particularly for lower projected strengths. In this work, a low Portland cement composition of SCC, with added metakaolin and fly ash (binary and ternary blended cements) was studied to evaluate its rheological and mechanical properties. Materials suitable for the mixture of the SCC were selected, characterized and the maximum packing density of the aggregates was determined. A SCC with a low compressive strength of 28.6 MPa and a cement consumption index of 10.2 kg m−3. MPa−1 was produced; these values are among the lowest obtained for this type of concrete. An index of 7.8 kg m−3. MPa−1 has been obtained for SCCs with higher compressive strength (67 MPa). Having defined a dosage strength of 25 MPa, a composition of 1:7.45 (cement:aggregates ratio) was obtained, with cement consumption of 222 kg/m3 (+49.4 kg fly ash and metakaolin) and a cement consumption index (binder index) of 10.8 kg m−3. MPa−1. The results show that it is feasible to produce low strength SCC, with the necessary fluidity and reduced binder consumption, when mineral additions of metakaolin and fly ash are used. This makes SCC more efficient, with important reductions in costs and environmental impact.