An approach to modified grinding aid for green cement production: synthesis, characterization, and compatibility with cement

This study presents a novel sustainable materials chemistry approach for enhancing cement performance by chemically modifying conventional based grinding aids (GAs). Amine- and glycol-based grinding aids (GAs), namely triisopropanolamine (TIPA), diethanol isopropanolamine (DEIPA), and diethylene glycol (DEG), underwent reactions with organic acids of different chain lengths to tailor their molecular structures and improve multifunctionality. The structural characterization of the modified GAs was conducted using Fourier-transform infrared spectroscopy. They were evaluated for their effects on cement grinding efficiency, particle size distribution, paste and mortar rheology, and mortar strength development. Compared with commercial counterparts, the modified GAs improved early-age compressive strength and rheological properties of cementitious pastes and mortars while also enhancing compatibility with polycarboxylate ether (PCE) based water-reducing admixtures was, especially for TIPA- and DEIPA-based systems. Modified GA systems significantly improved cement rheology and flow retention compared to the control and unmodified formulations. TIPA GA made with hexanoic acid exhibited the strongest effect, reducing viscosity by 21–86%, while DEG GA made with acetic acid achieved reductions of 5–69%. DEIPA modifications enhanced cement–PCE compatibility, leading to superior rheological behavior relative to unmodified DEIPA. Furthermore, TIPA, DEIPA, and DEG GAs made with each of propanoic acid, hexanoic acid, and propanoic acid, respectively, increased the 60-minute relative flow values by up to 15%, demonstrating improved workability retention. This advancement in research mitigates well-known admixture incompatibility issues and enables increased pozzolan incorporation without compromising workability or strength.