Advances in Science and Technology Vol. 108

Abstract: This article presents research and development on innovative photoactive admixtures for concrete and cement-based plasters for the finishing of concrete surfaces finished this year. The goal of the development was to provide the resulting surfaces of these newly developed materials with a self-cleaning ability stemming from photocatalytic reaction during exposure to UV radiation. The specific function of all these products is based on the photocatalytic oxidative mineralization of all organic structures present on the surface, i.e., their gradual transformation into the final simple inorganic compounds, which are carbon dioxide, water and the corresponding mineral acids. This research and development was carried out as part of a project supported by the Czech Ministry of Industry and Trade, in the TRIO programme; and in cooperation of BETOSAN s.r.o., the Technical University of Liberec, the Institute of Inorganic Chemistry of the Czech Academy of Sciences and the J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences. The first type of developed material is a photocatalytically active admixture in powder form, allowing the preparation of concrete surfaces with photocatalytic properties. The second type of developed material is a photocatalytically active cement-based plaster, intended primarily for application to a concrete substrate. Two final versions of both materials were developed. In the case of the plaster this means preparation of two colour variants, specifically white and grey. For the powder concrete admixture two types with different application procedures were developed. This means one version of admixture mixed throughout the entire volume of the concrete and second variant applied only in the surface layer of the concrete. We anticipate mainly exterior applications on the self-cleaning outer shell of buildings, as well as treatment of the surface layer of various structures such as bridges, noise barriers, traffic barriers and tunnels. The developed materials can also be used in interiors under specific conditions, with anticipated uses in the health care and food processing industries.

Abstract: Roads with cement concrete covers have a long tradition in the Czech Republic. They are used mainly on highway sections of roads with higher traffic intensity. The subject of this article is a brief description of communications with cement concrete cover. Furthermore, the determination of the expected time cycles of their maintenance and costs in the time axis of life from the perspective of Construction 4.0 and facility management. The article is based on TP 92 Design of maintenance and repairs of pavements with cement concrete cover [6]. The output is an interface in an Excel spreadsheet both in the current financial statement and in graphical form, which can serve as a basis for planning future repairs, including securing financial resources.

Abstract: The article deals with the construction of a geophysical observatory in the town of Fürstenfeldbruck, Bavaria, Germany. The observatory is being built for the Technical university in Munich. The main function of the observatory is to measure changes in the Earth ́s spin rate or, its axes deviations etc., which can occur with physical impulses in a form of, for example, an earthquake or nuclear explosion etc. Measuring such physical phenomena is important and the data is used to adjust navigation of satellites orbiting the Earth. As there were installed unique measuring tools in the building, the construction materials and building process itself has had to be carefully chosen and though through. The observatory is placed underground and has shape of a tetrahedron. The top of the construction is oriented in direction to the Earth ́s centre. To secure the pit the sprayed shotcrete was used and reinforced with AR Glass. To anchor the pit horizontally they also used the AR Glass. After finishing the pit, the central shaft was built and situated vertically from the top of the tetrahedron in direction to the Earth ́s surface and to the top of the tetrahedron base. Under a layer of concrete, there is a PE HD pipe DN 630 in every wall to connect the tetrahedron top with the base tops. There are several concrete shafts situated in each top tetrahedron base and also, at half of the span between the tetrahedron base tops. All these concrete shafts on the ground are interconnected by plinth beam with one another. The plinth beam contains three PE HD pipes DN 140. This type of construction was chosen as there is laser circling in the tetrahedron base, its top, and between tetrahedron top and base. In every shaft there is installed a measuring instrument, which is very sensible when in contact with steel parts. The sensibility to steel was a reason for employing only glass reinforcement GFK in every concrete part of this construction.

Abstract: Construction industry is one of the oldest industries in the world. It is the most manpower dependent industry in mankind civilization till now, very risky industry, and very slowly changing compared to other industries like IT hardware or car manufacturing for which a huge development took place to reduce, or may be eliminate, dependency on manpower.

Abstract: Nowadays, the safety of nuclear power plants is of increasing interest and importance. The main reasons for increased safety concerns are the recent major nuclear accident in Fukushima in 2011 and the overall tendency of environment protection. One of the possible ways of increasing the safety of nuclear power plants is the underground placement of all potentially dangerous systems under ground as the overlying soil or rock layer would act as a "earth" containment which would reduce the probability of ground level release following primary and secondary containment failure. Moreover, partial or total underground placement of nuclear power plant would reduce its visibility, and thus, public concerns would also be reduced. However, many design, operational, and economic disadvantages are linked with the underground placement of nuclear power plants. The aim of this paper is to provide state-of-the-art review of existing underground nuclear reactors, conceptual designs of underground nuclear reactors, and related literature, which can later be used for the design of a underground reinforced concrete containment building.

Abstract: In the last decade, the computing power of computers has significantly increased, which enabled very detailed and accurate numerical static non-linear analyses of reinforced concrete structures to be carried out using sophisticated commercial software. However, higher risk of errors, both in the calculation inputs and algorithm, is linked with the increased detail and accuracy of numerical modelling. For this reason, it is convenient to verify the results provided by sophisticated software using simplified analytical approaches. In order to provide a tool for quick and easy verification of results provided by sophisticated software, a novel web-based application employing simplified analytical methods has been developed by the authors of this paper. This web-based application is capable of quick and easy calculations of bending moments in reinforced concrete two-way slabs. For the calculation of bending moments, the Marcus Method is employed. This method introduces a correction coefficient to the Rankine-Grashoff Theory of Equal Deflections in order to account for the torsional restraints at the corners of the slab. These analytical methods are algorithmized and implemented using the JavaScript programming language. A graphical user interface for the input of data and for the interpretation of results is created using the HTML markup language. The novel web-based application is freely available and works on all common devices and operating systems. From the presented results, it is clear that the novel web-based application is quick, easily available, user-friendly, and intuitive. The web-based application can be used for the verification of the calculated bending moments during the design of a reinforced concrete two-way slab.

Abstract: Categorization of bridge constructions by the failure consequences due to loss of ultimate capacity or serviceability is a difficult task that can be resolved using two different approaches: elementary method using currently valid standards advanced method based on risk assessment. The elementary method is grounded on subjective assessment of bridge malfunctioning or collapse. The bridge is classified into an appropriate category (consequence class) in accordance with the most severe consequence. It is a simple procedure that may be applied without the need of demanding mathematical procedures. However, the resulting categorization may be affected by uncertainties in the assessment of consequences. The advanced method is based on a comprehensive analysis of bridge malfunctioning using a procedure of risk assessment. This method takes account of the occurrence probability of unfavourable events and the significance of individual consequences. Classification of a bridge construction into an appropriate category depends on the resulting risk of the bridge failure. This more laborious approach provides credible results without excessive uncertainties. The most adverse difficulty of the method is a combination of some consequences like the loss of life and economic costs. Both the above-mentioned approaches to the categorization of bridges by failure consequences can be effectively used depending on the type of bridge, on the intensity of exploitation, on expected consequences, and on social impacts of bridge malfunctioning.