Electroconductive cement-based composites are modern materials that are commonly used in many industries such as the construction industry, among others. For example, these materials can be used as sensors for monitoring changes in construction, grounding suspension, and resistance heating materials, etc. The aim of the research presented in this article is to monitor the impact of carbon particle character on cement-based electroconductive composites. Four types of graphite were analyzed. Natural and synthetic types of graphite, with different particle sizes and one with improved electrically conductive properties, were tested. For the analysis of the electrical conductivity of powder raw materials, a new methodology was developed based on the experience of working with these materials. Various types of graphite were tested in pure cement paste (80% cement, 20% graphite) as well as in a composite matrix, which consisted of cement (16.8%), a mixture of silica sand 0–4 mm (56.4%), graphite filler (20.0%) ground limestone (6.7%) and super plasticizers (0.1%). The resistivity and physical-mechanical properties of the composite material were determined. Furthermore, the resistivity of the test samples was measured with a gradual decrease in saturation. It may be concluded that graphite fillers featuring very fine particles and high specific surface are most suitable and most effective for creating electrically conductive silicate composites. The amount, shape and, in particular, the fineness of the graphite filler particles thus creates suitable conditions for the creation of an integrated internal electricity-conductive network. In the case of the use of a coarse type of graphite or purely non-conductive fillers, the presence of an electrolyte, for example, in the form of water, is necessary to achieve a low resistivity. Samples with fine types of graphite fillers achieved stable resistivity values when the sample humidity changed. The addition of graphite fillers caused a large decrease in the strength of the samples.

The use of superabsorbent polymers (SAP) in construction is a relatively new trend, and not a completely explored area. However, SAP itself has been on the market for over 80 years. SAPs have a cross-linked three-dimensional structure, thanks to which they have the unique ability to absorb extreme amounts of water, up to a hundred times their weight. By using this property, it is possible to prevent water losses, which is important at the time of maturation in cementitious building materials. When there is a lack of water needed for hydration processes, the physical and mechanical properties deteriorate. The subject of this article is to determine the possible positive effect of the presence of SAP in the cement matrix in order to optimize the parameters of silicate composites for 3D printing. For this purpose, a special methodology was compiled consisting of tests through which it is possible to assess the suitability of the tested mixtures for 3D printing. This methodology consists of determining consistency, volumetric weight, ultrasonic analysis, buildability, X-ray diffraction, flexural tensile and compressive strength. For determining of buildability and ultrasonic analysis new methodologies were created in this research in order to be suitable for the 3D printing materials. Last but not least, efforts are also being made to increase the incorporation of secondary raw material (fly ash) in order to reduce the environmental impact of industrial production and, conversely, to increase its sustainability while maintaining or improving the mechanical–physical parameters of building materials. From the results presented in this paper it is apparent, that created methodology is efficient for determining properties of 3D printable mixtures. SAPs also significantly influenced properties of these mixtures. Mainly buildability and flexural tensile strength (by up to 30%) were increased and volumetric weight was decreased (by up to 5%).

In this study, the suitability of waste from glass fibre production as a secondary filler for a polymeric durable hydrophobic coating, based on an innovative polyurethane organic–mineral base, was experimentally verified. The main aim of this work was to develop a basic formulation for a polymeric hydrophobic coating designed primarily for usage in aggressive environments. For this purpose, a total of four formulations were tested with different weight percentages of waste glass fibre, i.e., from 30 to 60%. The basic properties in the fresh state, such as the coating workability and kinematic and dynamic viscosity, were verified, and an application test was performed. The formulations were also verified after the polymerisation of the coating. Adhesion on a concrete substrate and the tensile properties and hardness of the coating were tested. Chemical resistance to liquid aggressive media and the microstructure of the coating after exposure to SO₂ were also tested, as these are critical properties. All the formulations showed better workability than the reference coating without a filler, and the formulation with the highest filling (60%) appeared to be optimal. The maximum adhesion on the concrete substrate (11.9 MPa) and tensile strength (21.6 MPa) were recorded for the formulation with 60% waste fibreglass. It can be concluded that with an increase in the waste glass content, there was a significant improvement in the properties of the coatings. Additionally, the waste fibreglass did not have a significant negative impact on chemical resistance.

The paper deals with problematics of the influence of size and shape of test specimens prepared according to the valid standard procedures in comparison to specimens prepared according to the standards used for different types of materials (grouts, coatings). The aim of this paper is to verify the possibility of using non-standard specimen sizes to reduce the economic demands of the development of building materials. The issue is tested on the polymer composites prepared in three different amounts of the filler. The polymer composite based on epoxy resin serves as a representative and homogenous material which achieves the same results under various curing temperatures and humidity. The porous structure of prepared samples was also studied and its effect on the selected mechanical properties was observed. It was shown that the specimen shape and size had impact on the mechanical properties of epoxy-based composites.

This paper deals with the study of chemical resistance of new cement-based grout for invert grouting. The aim of this work is to verify new mixtures with specific admixtures. The study monitors resistance to external sulphate attack. Specimens were placed into sulphate solution 29.8 g∙l^-1 (44 g∙l^-1 Na₂SO₄) according to DIN19753 standard. Based on the results gained, new mixtures will be designed and optimized by addition of suitable secondary raw materials (fly ash, waste foundry sand, waste glass, waste filers).

This paper deals with the problematics of polymer repair and adhesive mortars. In this study, the vinyl ester and epoxy resins filled with siliceous filler are used. This paper studies physical-mechanical properties and chemical resistance of developed mortars. The compressive strength, flexural strength and visual evaluation of reaction and degradation of polymer mortars in presence of common acids, alkalis and other compounds are compared. The results show, the amine-based epoxy mortar can withstand against a large variety of solutions, but the overall chemical resistance of vinyl ester mortar is higher.