QUANTITATIVE DETERMINATION OF BLAST-FURNACE SLAG CONTENT IN SLAG-BLENDED CEMENT BY COMBINATION METHOD OF HEAT-TREATMENT AND XRD/RIETVELD ANALYSIS

This paper described the estimating method for content of blast-furnace slag (BFS) in blast-furnace slag blended cement. Firstly unhydrated BFS was determined quantitatively by XRD/Rietveld method for heat-treated sample because the amorphous components of BFS were converted to crystalline phases, such gehlenite, akermanite and merwrinite, by heat treatment. The crystalline phases of heat-treated BFS sample were varied depending on the chemical composition of the BFS. During heat-treatment, a part of CaO from thermal decomposition of C₃S was enhanced in the presence of BFS. The free CaO reacted with BFS produced the crystalline phases, in particular merwrinite. This brought out a risk of overestimating the amount of BFS. In contract, it was also considered that reverse effect to produce the unexpected minerals, belite and anhydrite, which are apart from gehlenite, akermanite and merwinite, resulting in underestimate of the amount of BFS. In this paper, they are the trade-off interaction, and could be quantified theoretically.本研究は、非晶質である高炉スラグ微粉末（以下、スラグ）を加熱処理により結晶化させることで、X線回折リートベルト法により高炉セメント中のスラグ混合率を測定する手法を確立する目的で検討を行った。スラグ単独試料を加熱処理により結晶化した際の鉱物組成はスラグの化学組成に依存し、スラグ化学組成から結晶化後の鉱物組成の推定が可能であった。高炉セメント中のスラグ混合率をリートベルト法により測定する手法は、定量値が増減する双方の要因があり、その影響を定量的に明らかにしスラグ混合率を正確に測定できるスラグ化学組成の範囲を示した。