Effect of Activator Type on the High-Temperature Properties of Alkali-Activated Slag Cementing Fluid

The type of activator has a significant impact on the performance of alkali-activated slag, and there is little research on the effect of activator type on the high-temperature performance of alkali-activated slag. The effects of activator type on the thickening time, compressive strength, and rheological properties of alkali-activated slag under a high-temperature condition were studied in this article. Six activators were designed using Ca(OH)₂, Na₂CO₃, and Na₂SO₄ and their combination. The results show that there are obvious differences for the thickening time, compressive strength, and rheological properties of alkali-activated slag with different activators. In addition, the effect of activator type on AAM performance at elevated temperatures is distinct from that observed at room temperature. Among alkali-activated slag with six different activators, Ca(OH)₂-Na₂SO₄-activated slag has the best performance by considering the properties of thickening time, strength, and rheology under high temperatures. The low alkalinity of Na₂SO₄, producing NaOH by the reaction of Ca(OH)₂ and Na₂SO₄, and the reaction rate of Ca(OH)₂ and Na₂SO₄ can easily be controlled by the retarder, which may be responsible for the excellent performance of Ca(OH)₂-Na₂SO₄-activated slag.