Utilization of polyacrylamide-thickening agent and aluminum sulfate liquid accelerator for improving early strength of Portland cement.

This article investigates the combined effects of an aluminum sulfate alkali-free liquid accelerator (AFL) and a thickening agent polyacrylamide-based hydrogel (PAH) on the early compressive strength and hydration behavior of cement mortar, particularly for shotcrete applications. The study found that adding 8% AFL and 2% PAH synergistically promotes the rapid formation of ettringite (AFt) and other hydration products, resulting in a denser microstructure and significantly improved early strength (13.96 MPa at 1 day), although the 28-day strength slightly decreases. Excessive PAH (above 3%) reduces fluidity and delays final setting time by adsorbing on cement particles and hindering hydration. The research provides theoretical and practical insights into optimizing accelerator and thickener dosages to enhance early strength development in cementitious materials.