Research on synthesis and properties of amphoteric early strength polycarboxylate superplasticizer

Abstract

The amphoteric early strength polycarboxylate superplasticizer (AE-PCE) was synthesized by free radical aqueous solution polymerization, and using acrylic acid (AA), isobutylene alcohol polyoxyethylene ether (HPEG, molecular weight 4000) and dimethyl diallyl ammonium chloride (DMDAAC) as monomers. In this work, the structure of AE-PCE were characterized by FTIR, the hydration behavior of concrete were investigated by using TAM AIR isothermal microcalorimetry and scanning electron microscope, and properties of AE-PCE were studied by cement paste and concrete experimental. The results show that the quaternary ammonium cationic functional group has been successfully introduced into the molecular structure of polycarboxylate superplasticizer. The synthesized amphoteric early strength polycarboxylate superplasticizer (AE-PCE) can accelerate the hydration rate, significantly shorten the setting time and improve the early strength of concrete, and the effect of promoting coagulation and early strength is better than similar foreign products. Applied to the production process of subway shield segments, AE-PCE can effectively shorten the demoulding time of shield segments and improve the production efficiency under low temperature conditions in winter.