Influence of water - to - cement ratio and superplasticizer content on rheological propetries of fresh cement mortars

摘要

In framework of this thesis we carried out tests on fresh cement mortars. The main purposewas to find out how the water-to-cement ratio and superplasticizer content determinerheological characteristics of fresh cement mortar. With the use of the CEM method wedesigned four reference mortar mixtures, based on the composition of concretes that hadalready been determined and analyzed in some other thesis. Additional mixtures were thenmade by modifying the reference mortars, composition in such way that the content of wateror superplasticizer was varied. All mixtures were made of aggregate, cement, water andadmixtures. As admixtures we used superplasticizer and air entraining agent. We also usedtwo different types of cement. The tests were carried out using standard method of flow tabletests for fresh mortars and non-standard measurement of rheological properties by usingrheometer ConTec Viscometer 5. The main emphasis of the research work was onrheological measurements and the appertaining analyses of the obtained rheologicalparameters. Based on the analyses carried out we were able to confirm the findings fromliterature about the influence of water-to-cement ratio and superplasticizer content onrheological properties of fresh cement mortars. Finally, rheological parameters werecompared with the results of flow table tests.