Study on the Influence of Acrylic-Acid Addition Mode on the Performance of Polycarboxylate Slump-Retaining Superplasticizers

The study employed ethylene glycol monovinyl ether (EPEG) as the primary monomer and utilized a redox initiation system comprising hydrogen peroxide, ferrous sulfate, ascorbic acid, and mercaptoethanol. Through aqueous-solution free-radical polymerization, a polycarboxylate slump-retaining superplasticizer was synthesized. The research focused on the addition mode (pre-addition to the base mixture versus supplemental dosing in the liquid phase) and dosage of acrylic acid (AA), evaluating their effects on cement paste flowability, concrete expansion‑retention performance, and compressive strength. The results indicated that when AA was pre-added to the base mixture at a proportion of 30 % and the total acid‑ether ratio was set to 2.9, the resulting polycarboxylate slump-retaining agent achieved the optimal cement paste flow, the best concrete slump‑retention behavior, and the highest compressive strength.