Jan Trejbal

Dr. Jan Trejbal

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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24 May 2021 in Applied Sciences
Verified
Journal Article
Open access
PDF file
MDMária Domonkos
Mária Domonkos
PTPetra Tichá
Petra Tichá
JTJan Trejbal
Jan Trejbal
PDPavel Demo
Pavel Demo
In recent years, cold atmospheric pressure plasma (CAPP) technology has received substantial attention due to its valuable properties including operational simplicity, low running cost, and environmental friendliness. Several different gases (air, nitrogen, helium, argon) and techniques (corona discharge, dielectric barrier discharge, plasma jet) can be used to generate plasma at atmospheric pressure and low temperature. Plasma treatment is routinely used in materials science to modify the surface properties (e.g., wettability, chemical composition, adhesion) of a wide range of materials (e.g., polymers, textiles, metals, glasses). Moreover, CAPP seems to be a powerful tool for the inactivation of various pathogens (e.g., bacteria, fungi, viruses) in the food industry (e.g., food and packing material decontamination, shelf life extension), agriculture (e.g., disinfection of seeds, fertilizer, water, soil) and medicine (e.g., sterilization of medical equipment, implants). Plasma medicine also holds great promise for direct therapeutic treatments in dentistry (tooth bleaching), dermatology (atopic eczema, wound healing) and oncology (melanoma, glioblastoma). Overall, CAPP technology is an innovative, powerful and effective tool offering a broad application potential. However, its limitations and negative impacts need to be determined in order to receive regulatory approval and consumer acceptance.


1 July 2020 in Construction and Building Materials
Verified
Journal Article
Closed access
Václav NežerkaVáclav Nežerka
Václav Nežerka
PHP. Havlásek
P. Havlásek
JTJan Trejbal
Jan Trejbal

29 September 2020 in European Journal of Environmental and Civil Engineering
Verified
Journal Article
Closed access
RHR. Hlůžek
R. Hlůžek
JTJan Trejbal
Jan Trejbal
VNV. Nežerka
V. Nežerka
PDP. Demo
P. Demo
ZPZ. Prošek
Z. Prošek
PTP. Tesárek
P. Tesárek
Poor adhesion of synthetic macro fibers to a cementitious matrix limits their reinforcing capacity when used in fiber-reinforced cementitious composites (FRCCs). As a remedy to this problem, high concentrations of fibers must be incorporated into such mixtures, which makes their dispersion in fresh mixtures difficult to achieve. Several strategies have been adopted to improve bonding between synthetic fibers and a cementitious matrix, but most of them cause deterioration of fiber properties. In previous studies, plasma treatment of polymer fibers and strengthening of the fiber-matrix interface using recycled concrete powder (RCP) increased pull-out resistance at a scale of a single fiber. Here, it was found that these results cannot be easily scaled, and the tension-softening behavior of FRCCs can be influenced negatively, despite positive pull-out test results, due to random orientation of fibers. Treating fibers with plasma appears reasonable at any scale, but RCP matrix modification must be carefully performed. Nevertheless, RCP may contribute to more sustainable concrete mixtures and considering its use when designing FRCC elements is recommended.

21 March 2019 in Acta Polytechnica CTU Proceedings
Verified
Journal Article
Open access
PDF file
JTJan Trejbal
Jan Trejbal
TVTereza Valentová
Tereza Valentová
THTereza Horová
Tereza Horová
Asphalt mixtures often fail due to a low adhesion of bituminous binder to mineral aggregate, which leads to surface coarse damages like potholes and fatigue cracking. To avoid this phenomenon, different types of adhesion promoters may be admixed into bituminous binder but a new question about their effectiveness arises. This paper presents two semi-automatic methods, which reliably replace the subjective assessment. Both of them use a digital image of asphalt mixtures as an input. The first is based on a gray level thresholding, while the second one on an entropy-based image segmentation. Asphalt mixtures composed from Zbraslav aggregate (fraction 8–16 mm), paving grade bitumen 50/70 and several types of adhesion promoters were made and subjected to the adhesion assessment. It was shown that aggregate grains coated by binder was equal to ca. 83–88% in the case of reference binder, while that was increased by ca. 10–13% if whatever adhesion promoters were used.

1 December 2016 in Key Engineering Materials
Verified
Journal Article
Closed access
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JTJaroslav Topič
Jaroslav Topič
JTJan Trejbal
Jan Trejbal
PTPlachý Tomáš
Plachý Tomáš
ZPZdeněk Prošek
Zdeněk Prošek
This article deals with utilization of recycled concrete in form of high-speed milled powder into cement based materials. Recycled concrete powder in that form is used as microfiller and cement replacement. This article contains results of mechanical properties of the cement pastes with different amount of recycled concrete powder. The mechanical properties as the compressive strength, flexural strength, dynamic Young's and share moduli are observed during 409 days. According to results can be assumed that recycled concrete powder can be used as microfiller and cement replacement under 30 wt. % of total amount. Especially the results of compressive strength are comparable with reference sample. But there are some abnormalities in long term development of the strength that need to be explained.