Effect of alkaline additives on the physiochemical properties of high‐volume slag cement

Abstract The objective of this study is to examine the physiochemical changes that occur in high‐volume slag cement when additives with varying levels of alkalinity are introduced. The high‐volume slag cement blends were made by substituting 70% Portland cement with slag. For the additives, three different alkaline materials, namely volcanic ash, red mud, and cement kiln dust, were considered. The additives were added at 0%, 5%, 10%, and 15% by mass of high‐volume slag cement. The characteristics of high‐volume slag cement blends were examined by compressive strength, isothermal calorimetry, x‐ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, and porosity measurement. The results indicated that the alkaline additives have a beneficial effect on the early‐age strength development. However, the long‐term strength is compromised due to the alkalinity of the paste blends.