Study on the solidification and hydration release behavior of K+ ions in high-potassium cement clinkers under different silica modulus

Abstract

Recently, the widespread use of high‑potassium limestone has led to a sharp increase in the K₂O content in clinker, resulting in high‑potassium cement clinker. When mixed with water, high‑potassium cement clinker releases a significant amount of K⁺ ions in a short period, adversely affecting the performance of cement. Changes in the silica modulus can modify the proportion of silicate minerals and flux minerals that act as carriers of K⁺ ions, which in turn affects the solidification and the hydration rate of K⁺ ions. This study aims to investigate the influence of varying silica modulus in high‑potassium clinkers on the solid solution and hydration release rate of K⁺ ions and its influences on the mineral composition and hydration performance of high‑potassium clinkers. The results indicate that an increase in silica modulus leads to a decrease in the solid solubility of K⁺ ions in clinkers, resulting in a reduction in the ratio of C₂S-α′_L/C₂S-β and the ratio of C₃A-o/C₃A-c. Additionally, an increase in the silica modulus delays the sulfate depletion peak, retards the release of K⁺ ions, inhibits the transformation of AFt to Ms, and ultimately increases the compressive strength at 28 days.