*Article* **The Influence of Hydrated Lime and Cellulose Ether Admixture on Water Retention, Rheology and Application Properties of Cement Plastering Mortars**

**Edyta Spychał \* and Ryszard Dachowski**

Faculty of Civil Engineering and Architecture, Kielce University of Technology, 25-314 Kielce, Poland; tobrd@tu.kielce.pl

**\*** Correspondence: espychal@tu.kielce.pl

**Abstract:** In this article, the effect of hydrated lime and cellulose ether on the water retention, rheology, and application properties of plasters was studied. For mortars, the consistency, bulk density, and water retention were tested. Rheological measurements of pastes included yield stress and plastic viscosity. In addition to standard tests of mortars and examining the rheological properties of the pastes, a proprietary method for testing the application properties was proposed. The obtained research results made it possible to evaluate the performance of the tested plasters. An attempt was also made to correlate the rheological properties of pastes (plastic viscosity) to the water retention value. The influence of hydrated lime and cellulose ether on selected properties of pastes and plasters was also presented using the statistical Box–Behnken method. The subjective rating of an expert plasterer confirmed the necessity of the modification of plastering mortars with hydrated lime and cellulose ether. As shown, modification of cement plastering mortar with hydrated lime and cellulose ether at the same time allows obtaining a material with favorable technical and technological properties, especially mortars applied by machine.

**Keywords:** rheological properties; application properties; water retention; cement; hydrated lime; plaster; cellulose ether; viscosity
