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Composite materials reinforced with recycled fibers gather a great deal of interest with regards to construction applications. A novel polymer concrete composite was proposed, comprised of a surface layer and a structural composite reinforced with recycled glass fibers. The novel multi-material composite included a large amount of glass-fiber-reinforced polymer (GFRP) waste (30%), which is expected to help protect the environment. Large panels comprised of this polymer concrete composite, which reproduce the appearance of natural stone, were manufactured. A new methodology for porosity analysis of a large panel comprised of a multi-material composite was proposed, utilizing three-dimensional (3D) X-ray computed tomography (CT). The volume of pores was distributed between the constituent composite materials and then statistically analyzed. Homogeneous distribution of the pores within the novel multi-material composite was found. The observed mean porosities of the composite panel were 0.146% for the surface layer material and 31.3% for the structural composite material. The mean density of the panel, determined by the CT density method, was 1.73 g/cm 3 . The composite materials porosity provides a favorable effect for achieving lightweight structures. Using scanning electron microscopy (SEM) analysis, it was observed that a good connection interface between the constituent composite materials existed. possible recycling solutions regarding waste management of composite based products. At present, the main conventional recycling techniques for glass-fiber-reinforced polymer (GFRP) waste materials include incineration, thermal or chemical recycling, and mechanical recycling [1][2][3]. Mechanical recycling through grinding and milling processes is one of the most used techniques; additionally, due to the size reduction of the fibrous products, the recycling process itself does not contribute to atmospheric pollution and much simpler equipment is required as compared to other methods. From this process, the resulting fibers can then be incorporated into new composite materials.Within the construction field, polymeric composite materials are widely used (e.g., polymeric concrete composites), in which many industrial waste materials can be used as aggregates. One of the most commonly used aggregates for polymeric concretes is glass, which can be utilized in many different ways: glass fibers [4], glass dust, and inorganic waste in the form of coarse aggregates [5]. Polymer concretes produced with recycled materials and polyester resins provide aesthetic and structural benefits, as shown in a number of research studies [6,7]. GFRP waste materials incorporated into a polymer matrix are already used within many building materials, having the potential to reduce the environmental footprint of the materials used. Additional constituents of particulates in the polymeric matrix can be in the form of silica sand, calcium carbonate, mica, white cement, gypsum, perlite, or others [8,9]. The use of these materials enables the produ...

The article discusses the issue of on-line learning for Faculty of Materials Science and Technology in Trnava. This method of education was designed within the project KEGA: Realisation of on-line classroom for dynamic education of secondary technical school and university students focused on design and manufacturing of freeform surfaces. The main objective of this method of teaching is improving parent ́s faculty cooperation with detaches workplaces and increasing of the interest of secondary school students about studying on the college with technical orientation.

The use of additive technologies keeps growing. Increasingly, flammable powder materials are also used in additive technologies, and there is a risk of explosion or fire when using them. The current article deals with the determination of fire parameters of a powder sample of polyamide Sinterit PA12 Smoth in accordance with the EN 14034 and EN ISO/IEC 80079-20-2 standards. For that purpose, a sample at a median size of 27.5 µm and a humidity of 0% wt. was used. The measurements showed that the maximum explosion pressure of the PA12 polyamide sample was 6.78 bar and the value of the explosion constant Kst was 112.2 bar·m·s−1. It was not possible to determine the MIT value of the settled dust, since the melting point of polyamide sample is low. The MIT of the dispersed dust was 450 °C. Based on the measured results, it can be stated that the powdered polyamide PA12 poses a risk in terms of explosions and fires. Therefore, when using polyamide PA12 in additive technologies, it is necessary to ensure an effective explosion prevention.

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