AUTHORS: Michal Kropacek

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ABSTRACT: The paper describes experimental measurement of volume changes of cement composites. The first part of the experiment describes the measurement of volume changes of cement mortars. The mortars were designed in accordance with standard EN 196-1 [6]. Only the binder used differed in the mortars, which were Portland cements CEM I 42,5R from different production sites (5 cement plants). The second part of the experiment is the measurement of cement concrete under different conditions with using Portland cement CEM I 42.5 R as a binder. The concrete was designed in accordance with EN 206 [8] standard. Volume changes were measured by the shrinkage-drain, which allows to measure volume changes in the early setting and hardening phases. The volume changes of cement composites are a significant cause of negative symptoms, which can lead to cracks. The aim of the experiment was to assess the behavior of individual cements over a longer period in terms of volume changes and compare them among themselves. The experiment evaluates the stability of production of individual cements and, in view of the different input raw materials, compares the course of volume changes of cements from different cement plants. All Portlands cements comply with the requirements of the relevant EN 197-1 [7] standard, which, in the light of the results found, makes the experiment more unique. The experiment shows deviations in the composition and surrounding conditions that affect the final behaviour of mortar or concrete in terms of volume changes, which is beneficial to building practice and in particular to concrete technology. The experiment is also basis for calculation models, which will be the subject of further research.

KEYWORDS: Mortar, Concrete, Volume Changes, Shrinkage, Swelling, Portland cement, Shrinkage-Drain

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