Preparación y caracterización de cementos belíticos blancos activados con dopantes alcalinos

Activated white cement clinkers with a theoretical 60% (wt) belite (dicalcium silicate) content were prepared at a temperature 100 oC lower than used to manufacture conventional white Portland cement clinkers. Activation was achieved by adding variable amounts of K 2 CO 3 or Na 2 CO 3 to the raw mixes. Rietveld quantitative analysis of X-ray diffraction findings showed that adding the alkalis stabilized the high temperature belite polymorphs. When 2.0% (wt) of Na 2 O was added, the composition (by wt) found was 16.4(4)% alpha-C 2 S, 16.7(8)% alpha’- H -C 2 S, 23.2(6)% beta-C 2 S, 32.7(7)% total C 3 S, 9.5(2)% orthorhombic C 3 A and 1.50(5)% free lime. Due to the high volatilization rate of K 2 O under the experimental conditions, it stabilized the alpha-type C 2 S less effectively than Na 2 O. A calorimetric study was likewise performed to correlate the phase composition with early age hydration (behaviour).