Search

Your search keyword '"Jan Sklenka"' showing total 3 results
Start Over Author "Jan Sklenka"
3 results on '"Jan Sklenka"'

1. Magnesium oxychloride cement with phase change material: Novel environmentally-friendly composites for heat storage

Author

Anna-Marie Lauermannová, Milena Pavlíková, Zbyšek Pavlík, Adam Pivák, Adéla Jiříčková, Jan Sklenka, Martina Záleská, Květoslav Růžička, and Ondřej Jankovský

Subjects
Magnesium oxychloride cement, Phase change material, Thermal performance, Latent heat storage, Mechanical and hygric parameters, Mining engineering. Metallurgy, TN1-997
Abstract

To solve heat energy storage of building enclosure systems, phase change materials (PCMs) were implemented into magnesium oxychloride cement (MOC) to form a MOC-PCM composite. Such composites possess sufficient mechanical strength for specific usage and high heat storage efficiency. The chemical and physical properties of raw materials were investigated as well as fresh composite mixture rheology. On matured samples, structural, mechanical, hygric, and thermal properties were tested. The results suggest that the enrichment of MOC with PCM particles causes an increase in porosity, hence a decrease in the specific density of the composites. With each addition of PCM the reduction of mechanical properties of the composite material occurs, where the maximum reduction in flexural and compressive strength for the sample with 40 wt % of PCM is around 80%. The low strength of the composite is compensated by excellent thermal properties that are required for its intended application. The enthalpies of phase changes increased linearly with the dosage of PCM and can contribute to the passive moderation of temperature fluctuations. The developed composites can find use in building engineering in the form of indoor cladding panels, facing slabs ceiling boards, etc. Which can be beneficially applied for example in the passive cooling of attic rooms and retrofitting of the present building stock.

Published
2022
Full Text
View/download PDF

3. Magnesium oxychloride-graphene composites: Towards high strength and water resistant materials for construction industry

Author

Michal Lojka, Martina Záleská, Anna-Marie Lauermannová, Jan Sklenka, Ondřej Jankovský, Adam Pivák, Zbyšek Pavlík, and Milena Pavlíková

Subjects
Curing (food preservation), Materials science, Graphene, Composite number, Young's modulus, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, chemistry.chemical_compound, symbols.namesake, Compressive strength, chemistry, Flexural strength, law, Materials Chemistry, Ceramics and Composites, symbols, Reactive magnesia, Composite material, Porosity
Abstract

This paper deals with research concerning the graphene-doped construction materials, namely with the optimization of the ideal content of the nanoadditive in the final composite. This research was conducted building on the previous studies on use of graphene in magnesium oxychloride cement (MOC). The evaluation of the effect of the graphene nanoplatelets based on their content was performed using various analytical methods as well as mechanical tests. Among the used methods are XRF, SEM, EDS, HR-TEM, XRD and OM. After 28 days of air curing, the mechanical, macro- and micro-structural parameters were studied. One of the main characteristics of the materials was their porosity, which was thoroughly studied in order to determine the influence of the graphene on its drop. This parameter is very important for the MOC-based materials, hence it is directly connected to their resistance to water. The compressive strength of the sample containing 1 wt% of graphene reached value of 99.7 MPa. This sample has shown a massive increase in both compressive (26.8 %) and flexural strength (14.9 %) as well as in the modulus of elasticity (73.1 %) in comparison with the reference sample which did not contain any additives. The developed composite materials show a promising route in the controlled improvement of reactive magnesia-based construction materials properties using carbon-based nanoadditives.

Published
2021

Catalog

Books, media, physical & digital resources
See catalog results