Impact of water-soluble cellulose ethers on polymer-modified mortars

Cellulose ethers (CEs) are employed in many polymer-modified mortars, such as cement renders, masonry mortars, tile adhesives, repair mortars, skim coats, and self-levelling mortars. The addition of CEs to mortars causes the retardation of cement hydration and modifies the microstructural characteristics and the properties of these mortars. The present work attempts to provide a comprehensive review of the current state of knowledge on the effects of CEs and critically identifies gaps in the knowledge. A fundamental scientific understanding concerning the chemistry and hydration of cement, chemical natures, and relevant properties of CEs are discussed. The behaviours and mechanisms of CE adsorption on cement are assessed. The influences of CEs on the kinetics of cement hydration, mechanisms of retardation, and microstructural evolution of the mortars also are reviewed. Finally, the impact of CEs on the properties of fresh and hardened mortars as well as the approaches used to mitigate the negative impacts of CEs are discussed.