Preparación y caracterización de cementos belíticos blancos activados con dopantes alcalinos

Abstract

Activated white cement clinkers with a theoretical 60% (wt) belite (dicalcium silicate) content were prepared at a temperature 100 °C lower than used to manufacture conventional white Portland cement clinkers. Activation was achieved by adding variable amounts of K2CO3 or Na2CO3 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 Na2O was added, the composition (by wt) found was 16.4(4)% α-C2S, 16.7(8)% α'H-C2S, 23.2(6)% β-C2S, 32.7(7)% total C3S, 9.5(2)% orthorhombic C3A and 1.50(5)% free lime. Due to the high volatilization rate of K2O under the experimental conditions, it stabilized the alpha-type C2S less effectively than Na2O. A calorimetric study was likewise performed to correlate the phase composition with early age hydration (behaviour).