Influence of High-Robustness Polycarboxylate Superplasticizer on the Performances of Concrete Incorporating Fly Ash and Manufactured Sand

Abstract

Using ethylene glycol monovinyl polyoxyethylene ether, 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and acrylic acid as the main synthetic monomers, a high robustness polycarboxylate superplasticizer was prepared. The effects of initial temperature, ratio of acid to ether, amount of chain transfer agent, and synthesis process on the properties of the superplasticizer were studied. The molecular structure was characterized by GPC (Gel Permeation Chromatography) and IR (Infrared Spectrometer). As shown by the results, when the initial reaction temperature is 15°C, the ratio of acid to ether is 3.4:1 and the acrylic acid pre-neutralization is 15%, The AMPS substitution is 10%, the amount of chain transfer agent is 8%, and the performance of the synthesized superplasticizer is the best. Compared with commercially available ordinary polycarboxylate superplasticizer in C30 concrete prepared with manufactured sand and fly ash, the bleeding rate decreases by 52%, T50 decreases by 1.2 s, and the slump time decreases by 1.1 s. In C60 concrete prepared with fly ash and river sand, the bleeding rate decreases by 46%, T50 decreases by 0.8 s, and the slump time decreases by 3.2 s.