Effect of Cellulose Ether and Starch Ether on Hydration of Cement Processes and Fresh-State Properties of Cement Mortars

Abstract

The production of factory-made mortars is a multicomponent system. Viscosity-modifying admixtures (VMAs) are an inherent ingredient of these materials. The correct choice of the amount and type of these admixtures is important from the practical and scientific points of view. In this article, the use of cellulose ether (CE) and starch ether (SE) in cement pastes and mortars is studied. This research focuses on the hydration process and fresh-state properties of mortars because this subject determines the correct choice of the amount and type of admixture used, and the results determine the application and properties of hardened mortars. Polymers were added in the range from 0.056% to 0.22% in relation to the dry ingredients of the mortar. The research showed that cellulose ether had the greatest impact on the consistency, air content, bulk density, and water retention of ordinary dry-mix mortars. On the other hand, starch ether affected the hydration process, delaying the setting and hardening processes much more than cellulose ether. The action of these admixtures rose with the increase in the amount of polymer used in different ways (depending on the type of ether).

Physico-Mechanical Properties and Hydration Processes of Cement Pastes Modified with Pumice, Trass and Waste Chalcedonite Powder

“…The changes in heat evolution for the first 7 days of the setting and hardening processes were monitored. The temperature of the calorimeter was constant and equal to 25 • C. Additionally, the degree of hydration was calculated for all samples, according to the pattern given in publication [50]. All dry ingredients were weighed and poured into a measuring box (small jar) (Figure 4a) and then the appropriate amount of water was measured (Figure 4b).…”