Preparation of portland cement components by poly(vinyl alcohol) solution polymerization

The four components of portland cement - dicalcium silicate, C₂S (Ca₂SiO₄); tricalcium silicate, C₃S (Ca₃SiO₅); tricalcium aluminate, C₃A (Ca₃Al₂O₆); and tetracalcium aluminate iron oxide, C₄AF (Ca₄Al₂Fe₃O₁₀) - were formed using a solution-polymerization route based on poly(vinyl alcohol) (PVA) as the polymer carrier. The powders were characterized using X-ray diffraction techniques, BET specific surface area measurements, and scanning electron microscopy. This method produced relatively pure, synthetic cement components of submicrometer or nanometer crystallite dimensions, high specific surface areas, as well as extremely high reactivity at relatively low calcining temperatures. The PVA content and its degree of polymerization had a significant influence on the homogeneity of the final powders. Two types of degree of polymerization (DP) PVA were used. Lower crystallization temperatures and smaller particle size powders were obtained from the low-DP-type PVA at optimum content.