The rheology of cement pastes with addition of hydrated lime and cellulose ether in comparison with selected properties of plastering mortars

The article presents the results of the investigation on pastes and cement mortars modified with lime and cellulose ether. Rheological measurements of pastes included yield stress and plastic viscosity. For mortars, bulk density, air content, shrinkage and water retention value were determined. Setting and hardening process was tested by the ultrasonic method, completed with a compressive strength test. The test results confirmed the beneficial effect of hydrated lime and cellulose ether addition on the properties of fresh plaster. The addition of cellulose ether increased the water retention coefficient by at least 10% compared to mortars without cellulose ether. The effect of cellulose ether on water retention in mortar was more significant than that of hydrated lime. Both cellulose ether and/or hydrated lime causes setting retardation as well as decrease the rate of hardening. Compressive strength is decreased while shrinkage deformation is reduced.