Investigation on the optimal chemical structure of methacrylate ester based polycarboxylate superplasticizers to be used as cement grinding aid under laboratory conditions: Effect of anionicity, side chain length and dosage on grinding efficiency, mortar workability and strength development

Abstract

Using polycarboxylate ether/ester (PCE) superplasticizers as cement grinding aid presents an interesting concept because the PCE could provide both grinding and fluidizing effect at the same time, thus achieving two benefits from the admixture. Here, a systematic study on the relationship between the molecular structure of ω-methoxy poly(ethylene glycol) methacrylate ester based PCE (MPEG-PCE) and their grinding efficiency was performed. A series of MPEG-PCEs with systematically modified compositions was employed and their impact on grinding efficiency was assessed. First of all, the PCE dosage required to achieve a certain fineness in a laboratory ball mill was determined. Then, the grinding efficiency of PCEs exhibiting different anionic charge density and side chain length was investigated. It was found that an optimal molar ratio of carboxylic acid : side chain exists, and that shorter side chains are more beneficial for grinding efficiency than longer ones. Furthermore, it was also found that intergrinding of MPEG-PCEs with clinker produces a cement with higher fluidity.