A comparative study between reference-concrete (RC), silica fume (SF) and high reactivity metacaulim (MCAR) was done. The performances were tested in terms of the compressive and tensile strength by diametrical compression. Comparative cost analyses were carried out by taking into account the binders consumption at the same strength, and also the Brazilian product prices. The total consumptions of cimentitious materials studied were in the range of 180 kg/m³ to 650 kg/m³. The replacement of 8% (w/w) of MCAR and SF over cement weight was enough to inhibit alkali-aggregate reaction, investigated whitout cement admixtures. Both additions provided bennefit in terms of cost and mechanical resistance in the first ages (90 days), been equivalently.
concrete; silica fume; metakaolin
