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This article presents the results of experimental research on the possible use of construction and demolition waste (CDW) to improve the properties of unburnt tailings originating from the thermally active spoil heap in Heřmanice (Ostrava, Czech Republic). Mining activity anywhere in the world generally entails a lot of negative impacts on the environment, which are of a long-term nature. One of the most pressing challenges in the remediation of the consequences of mining activity is the thermal activity of spoil heaps associated with the high acidity of the tailings. Active acidity (pH/H2O), exchangeable acidity (pH/CaCl2), hydrolytic acidity (Ha), and elemental composition of tailings and CDW have been monitored. Based on an acidity study, it has been proven that compared to burnt tailings (pH/H2O = 8.4, pH/CaCl2 = 8.9 and Ha = 1.4 mmol kg−1), unburnt tailings show acidic properties (pH/H2O = 3.7, pH/CaCl2 = 3.6 and Ha = 205 mmol kg−1). The bioavailability of two selected potentially toxic elements (PTEs), namely Al and Fe, was examined based on the elemental composition. BCR sequential extraction analysis was used to determine their bioavailability. It has been proven that mixing CDW with tailings has a positive effect on the pH value, which has a positive effect on the further development of the entire site. The increase in the pH value is provably dependent on the amount of construction waste added, so it can be said that the increasing amount of construction waste will result in improved parameters of the burnt tailings. The results of the BCR analysis show that aluminum from the tailings will be released both from the reducible and oxidisable fractions, where it will be mainly bound to sulphides. The relatively high concentration of Fe in the oxidisable fraction (2002 mg Fe kg−1) suggests that Fe is bound to sulphides in the tailings, and it is due to the high residual pyrite and sulphide content in the dumped material, as expected. This work has found no limits where CDW no longer positively affects the acidity of unburnt tailings. For practical application, however, it is important that the mixture of CDW and tailings is properly mixed and then used for remediation.

The research was dealing use of ladle slag and its impact on the physical and mechanical parameters of hardened cement composites. The goal was to find a suitable percentage share of ladle slag used as an admixture. The results of compressive strength tests show the possibility of replacement of a significant amount of cements with a specific secondary product. A decrease in compressive strength of about 8% after 28 days has to be taken into account when using Portland cement CEM I 42.5R and a 10% replacement with ladle slag.

This article presents the results of a study dealing with the use of a combination of recycled rubber from waste tires as a 100% replacement of aggregate and waste sludge water from a concrete plant as a partial replacement of mixing water in the production of cement composites. The aggregate was replaced with recycled rubber material in two ratios. The first ratio was 50/50 and the other one was a 40/60 ratio of fraction 0/1 mm and fraction 1/3 mm. The mixing water was replaced with waste sludge water from a concrete plant in the amounts of 25% and 50%. The designed cement composite formulas were subjected to the test of their physical and mechanical characteristics in order to determine the properties when using a combination of recycled rubber and waste sludge water from a concrete plant. The tested properties include: consistency of the grain curve, mixing water properties, consistency of cement mortar, strength characteristics (tensile flexural strength and compressive strength). The study presents the results that are fundamentally different from the comparative samples and their use in the building industry but, at the same time, they also open up new possibilities of their use as building material.

This article presents the results of research on the use of unstable steel slag with a fraction of 0/8 mm as a 100% substitute for natural aggregate in concrete production. Two types of cements were used for the production of concrete: Portland cement CEM I 42.5N and hybrid cement H-CEMENT. Both of these cements were produced by the company Považská cementárna, a.s., Ladce. The main objective of this study was to assess the suitable type of binder to be combined with unstable steel slag in the production of concrete composite. The prepared concrete was used to test the properties of a fresh concrete mix, i.e. its consistency and bulk density. Hardened concrete was used to test the strength and deformation properties, including cube strength after 3, 7, 14, 21, 28 and 90 days, as well as prism strength after 28 days. The static modulus of elasticity was determined using prisms after 28 days of age of the test specimens. Our attention was also focused on determining the class of leachability of the concretes based on steel slag with CEM I 42.5N and H-CEMENT. The durability of concrete prepared on the basis of steel slag was tested in an environment with increased temperature and pressure. The results of the strength characteristics tests show a difference between the 28-day average cube strength of concrete using CEM I 42.5N and H-CEMENT (34.6 MPa and 29.1 MPa), while after 90 days, the average cube strength value stabilized at about 38 MPa. The average values ​​of the static modulus of elasticity when using CEM I 42.5N and H-CEMENT are almost identical, achieving values ​​of 32.5 GPa and 32.8 GPa, respectively. Concrete based on steel slag with CEM I 42.5N and H-CEMENT can be included in leachability class IIb. The results of the durability test of concrete based on steel slag in an environment with increased temperature and pressure confirmed the use of H-CEMENT hybrid cement from the company Považská cementáren, a.s., Ladce, as a suitable binder. .

This paper is aimed to investigate the total sand filler replacement by two types of cellulosic fibers (bleached wood pulp - WP and recycled fibers from waste paper - RF) in cement-based mortars. Two different types of cement mortar, one with addition of finely ground limestone and other with powdered granulated slag, were mixed with fibers. The changes in consistency of fresh fiber cement mortars and development of compressive and flexural strength of mortars in dependence on hardening time up to 90 days was studied. The development of compressive and flexural strength with increasing hardening time of cellulose fiber mortars and two binders with different properties confirmed that binder mixtures containing finely ground slag and recycled cellulose fibers achieved higher values of these strength parameters. Also adhesion testing of fiber cement mortars on two substrates (ceramic fitting and aerated concrete block) after 28 days of their application showed better adhesion of cement mortars with finely ground granulated slag on the ceramic fitting surface compared to the mortars containing finely ground limestone. However, any cracks have occurred on both substrates during the maturing of mortars with slag. Based on the above facts, it can be concluded that suitable plaster mixtures for their use in the interior appear the cement recipes with both cellulose fibers (wood pulp and fibers from recycled waste paper) and with finely ground limestone.

This article presents the results of a study dealing with the use of a combination of recycled rubber from waste tires as a 100% substitute in the production of cement composites. Aggregate was replaced with recycled rubber in two ratios, namely the ratio of 50/50 and the ratio of 40/60 of the share of fraction 0/1 mm and fraction 1/3 mm. The designed formulas of cement composites were subjected to the tests of their physical and mechanical properties in order to determine the properties of the used recycled rubber combination. The tests included the consistency of the grain curve, mixing water properties, consistency of cement mortar, and strength characteristics (tensile flexural strength and compressive strength). The study presents results that are fundamentally different from the comparative samples and their use in the building industry; however, at the same time, they open up new possibilities of their utilization as a building material. Keywords: Composite; Concrete; Mixing water; Recycled rubber granulate; Waste tire DOI 10.35180/gse-2020-0028

The aim of this study was to characterize two types of cellulosic fibers obtained from bleached wood pulp and unbleached recycled waste paper with different cellulose content (from 47.4 percent up to 82 percent), to compare and to analyze the potential use of the recycled fibers for building application, such as plastering mortar. Changes in the chemical composition, cellulose crystallinity and degree of polymerization of the fibers were found. The recycled fibers of lower quality showed heterogeneity in the fiber sizes (width and length), and they had greater surface roughness in comparison to high purity wood pulp samples. The high purity fibers (cellulose content > 80.0 percent) had greater crystallinity and more homogeneous and smooth surfaces than the recycled fibers. The presence of calcite and kaolinite in all of the recycled cellulosic fibers samples was confirmed, whereas only one wood pulp sample contained calcite. The influence of the chemical composition was reflected in the fiber density values. Changes in the chemical composition and cellulose structure of the fibers affected the specific surface area, porosity and thermo physical properties of the fibers. More favorable values of thermal conductivity were reached for the recycled fibers than for the wood pulp samples. Testing the suitability of the recycled fibers with inorganic impurities originating from the paper-making processes for their use as fillers in plastering mortars (0.5 wt.% fiber content of the total weight of the filler and binder) confirmed their application by achieving a compressive strength value of 28 day-cured fiber-cement mortar required by the standard as well as by measured more favorable value of capillary water absorption coefficient. Web of Science 7 11 1145 1121

This article describes an experimental study aimed at investigating the potential use of recycled rubber granulate from waste tires of fractions 0/1 and 1/3 mm in cement composites as a 100% replacement for natural aggregates. The use of waste in the development and production of new building materials represents an important aspect for the sustainability and protection of the environment. This article is focused on the sound-absorbing and thermal-insulating properties of experimental cement composites based on recycled rubber from waste tires. The article describes the grain characteristics of recycled rubber, sound absorption capacity, thermal conductivity and strength characteristics. The results of this research show that the total replacement of natural aggregate with recycled rubber in cement composites is possible. Replacing natural aggregate with recycled rubber has significantly improved the thermal and acoustic properties of the prepared cement composites, however, at the same time, there was also the expected decrease in the strength characteristics due to the elasticity of rubber.

This article presents the results of research that dealt with the development of non-traditional concrete using a hybrid alkali-activated cement. It is concrete based on by-products from a metallurgical plant that replaced 100% of the natural aggregates. Steel slag (CSS, fraction: 0/8 mm) was used as a filler in combination with air-cooled slag (ACBFS, fraction: 8/16 mm and 16/32 mm). Portland blended cement (CEM II/B-S 42.5N) and H-CEMENT were used as binding components in the development of the concrete mixture designs. Both of these cements were produced by Považská cementáreň, a.s., Ladce. Attention was focused on testing the physical and mechanical properties of the developed concretes in various environments. An aqueous environment was selected as the first environment for the placement of test specimens (cubes with 150 mm edges and prisms with dimensions of 100 × 100 × 400 mm3) according to the ČSN EN 206-1 standard and the outdoor environment (August to October). The determination of the cube strength was made after 7, 28, and 90 days, the determination of the flexural and compressive strength was made at the end of the prisms, and the determination of the dynamic modulus of elasticity was made after 28 days on the prisms. The test results of the test specimens, which were placed in two environments, were compared and it was found that, after 90 days, the outdoor environment caused a decrease in the concrete’s strength characteristics when using Portland blended cement (CEM II/ B-S 42.5N) of about 8%, in contrast, when using H-CEMENT, the concrete’s strength increased by about 14%. The use of H-CEMENT and the addition of PUZZOLANIT in the amount of 30% in combination with CEM II/B-S 42.5N in the amount of 70% reduced the decrease in the strength of the concrete after 90 days by about 3%. The research results confirm the suitability of using H-CEMENT and the addition of PUZZOLANIT for the production of concrete based on steel slag (CSS) and air-cooled slag (ACBFS).

Sustainability in the construction industry refers to all resource-efficient and environmentally responsible processes throughout the life cycle of a structure. Green buildings may incorporate reused, recycled, or recovered materials in their construction. Concrete is as an important building material. Due to the implementation of by-products and waste from various industries into its structure, concrete represents a significant sustainable material. Steel slag has great potential for its reuse in concrete production. Despite its volume changes over time, steel slag can be applied in concrete as a cement replacement (normally) or as a substitute for natural aggregates (rarely). This paper focused on an investigation of concrete with steel slag as a substitute of natural gravel aggregate. Testing physical and mechanical properties of nontraditional concrete with steel slag as a substitute for natural aggregates of 4/8 mm and 8/16 mm fractions confirmed the possibility of using slag as a partial replacement of natural aggregate. Several samples of concrete with steel slag achieved even better mechanical parameters (e.g., compressive strength, frost resistance) than samples with natural aggregate. Moreover, a life cycle assessment (LCA) was performed within the system boundaries cradle-to-gate. The LCA results showed that replacements of natural aggregates significantly affected the utilization rate of nonrenewable raw materials and reduced the overall negative impacts of concrete on the environment up to 7%. The sustainability indicators (SUI), which considered the LCA data together with the technical parameters of concrete, were set to evaluate sustainability of the analyzed concretes. Based on the SUI results, replacing only one fraction of natural gravel aggregate in concrete was a more sustainable solution than replacing both fractions at once. These results confirmed the benefits of using waste to produce sustainable materials in construction industry. Web of Science 12 23 art. no. 9873

This study investigates the mechanical properties and durability of three families of high-performance concrete (HPC), in which the first was blended with fly ash, the second with circulating fluidized bed combustion (CFBC) ash, and the third with CFBC slag. In addition to each of the three mineral additives, silica fume and a superplasticizer were also incorporated into the HPC. Hence, three families of HPC, containing 10%, 20%, and 30% mineral admixtures and 9% silica fume of the binder mass, respectively, were produced. The microstructure and hydration products of the HPC families were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) to explore the influence of fly ash, CFBC ash, and CFBC slag on the compressive strength and frost resistance of HPC. The experimental results show that the compressive strength of HPC could reach 60 MPa at 28 d age. When the fly ash content was 30%, the compressive strength of HPC was 70.2 MPa at 28 d age; after the freeze-thaw cycle, the mass loss and strength loss of HPC were 0.63% and 8.9%, respectively. When the CFBC ash content was 20%, the compressive strength of HPC was 75 MPa at 28 d age. After the freeze-thaw cycle, the mass loss and strength loss of HPC were 0.17% and 0.81%, respectively.

Flying used to be a phenomenon of big airliners. It is now an ever-growing reality to see air carriers operating small aircraft too. Business jets are today frequent visitors to worldwide airspaces and airports. By gradual upgrades of the equipment (both aircraft and infrastructure) the character of business aviation changes significantly its nature. From the perspective of flight preparation and flight planning these flights range between the most complicated ones. In the business aviation community little attention is often paid to the importance of dimensioning their operation control centers (OCC). This paper shows typical capacity issues and available solutions to help optimize the OCCs capacity setup.

This article presents the results of an experimental research dealing with the measurement of the thermal characteristics of concretes based on natural and artificial aggregates (steel slag). The samples of concrete composites were prepared on the basis of natural aggregate fractions 0/4, 4/8 and 8/16 mm and on the basis of steel slag fr. 4/8 mm. The volume ratio of the individual aggregate fractions in all experimental mixtures used for the production of concrete composites was 40:30:30 (fr. 0/4: 4/8: 8/16). The prepared samples of concrete composites based on natural aggregate and natural aggregate combined with steel slag were subjected to the tests of strength characteristics, water-tightness, thermal characteristics using a commercial device ISOMET 2104 (measurement of the coefficient of thermal conductivity λ, specific heat capacity c, and the coefficient of thermal diffusivity a), and heating in a prototype calorimetric computer-controlled chamber. The main attention was focused on the testing of the value changes of the coefficients of thermal conductivity λ depending on the changes of temperatures within the range of -5 °C to + 40 °C. The measurements of these thermal characteristics have very high informative value, especially because these material parameters are not tabulated for the newly designed building materials, and that is why they are not examined at extreme temperatures. This is a reason why they cannot be used as important data during the thermal calculations of a non-insulated concrete structure (e.g. using polystyrene and / or glass wool).

Wood plastic composite (WPC) materials represent modern materials that are attracting interest worldwide. WPC are composite materials and they have properties of both components – plastic and wood. WPC materials are formed by combining two substances – discontinuous reinforcements (wood particles or cellulose microfibers) and a continuous binder (plastic matrix), in a certain proportion. The authors describe WPC machined surfaces after turning. On the basis of a set of experimental data collected by surface and mechanical tests obtained from the WPC materials, the mechanical deformation work was evaluated, the value of which presents specific information about the material as a specific material coefficient.

This chapter is devoted to the preparation of the data necessary for the individual stages of design documentation concerning the design of sewerage system, sewer connection, water supply, and water-service pipe. It does not deal with the specific design of the above-mentioned constructions, but it introduces the minimum requirements resulting from the existing legislation in force in the Czech Republic. It also outlines the possibilities of various permission modes for these constructions and deals with the obligations of the owners of these constructions and the possible sanctions for administrative offenses in the Water Act section.

The article deals with testing and evaluating the mould resistance of carbide lime by-product from deposits in comparison with the effect of reference conventional slaked lime. The mould resistance of limes was tested on a mixture of mould such as Gliocladium virens, Paecilomyces variotii, Penicillium funiculosum, Chaetomium globosum, and Aspergillus niger as well as evaluated according to the method stated in the technical standard STN 724310: 1993. The evaluating scale for mould resistance is from 0 up to 5 in the fungal growth degree (FGD). The FGD value 0 stands for no fungal growth comes about and construction materials and products have the microbiostatic effect against filamentous fungi. The experiments confirm the microbiostatic effect against mould of carbide lime by-product from deposits as well as reference conventional slaked lime; however, the microbicidal effect against mould has not been confirmed at all; the inhibiting area-zone-did not form on the agar growth media around the tested samples. Application of carbide lime by-product from deposits ensures increased mould resistance of construction materials with the microbiostatic effect against mould in accordance with technical standard STN 724310: 1993. Web of Science 73 10 2582 2575

Energy rehabilitation of buildings using airtight insulating materials based on expanded polystyrene is often accompanied by the formation of moisture problems in the enclosure wall footing. Moisture progress in the rehabilitated structure is simulated using modern moisture transient models in Delphin software. Combinations of the developed plate thermal insulating materials based on calcium silicate and the conventional thermal insulation panels based on expanded polymer have been designed to address the moisture problems. This article describes the function of this solution during the reconstruction of a house built from full clay bricks with malfunctioning waterproofing in the lower house construction.

Anzeichen von Feuchtigkeit in den Anschlussfugen von Fensterkonstruktionen sind ein typisches Merkmal des zeitgenossischen Bauingenieurwesens. Diese Probleme treten sowohl in Neubauten als auch in rekonstruierten historischen Gebauden auf. Sie manifestieren sich als nasse Flecken oder schwarzer Schimmel auf Fensterlaibungen, Ecken und Kanten. Dieser Artikel beschreibt eine zerstorungsfreie Losung dieser Probleme mit Hilfe einer Betonabdichtung in einem bestehenden Gebaude mit langandauernden Zeichen von Feuchtigkeit in den Fensteranschlussfugen. Die Beseitigung dieses Problems liegt in der Anwendung eines entwickelten Calciumsilikatmaterials fur Feuchtigkeit und der thermischen Sanierung der Gebaude. Dieser Artikel beschreibt die Eigenschaften des neu entwickelten Materials auf Basis eines Zementverbundes mit Aluminiumoxid-Silikat-Fullstoff. Das Endprodukt verwendet die gleichen Prinzipien des Feuchtigkeitstransports, wie die weitverbreiteten autoklavierten Calciumsilikat-Isolierungen. Im Vergleich zu den ublicherweise verwendeten Materialien ist das entwickelte Material dadurch einzigartig, dass die hydrothermale Aushartung in einem Autoklaven weggelassen werden kann. Das neue Material mit einer definierten Kapillarstruktur nutzt auch Flugasche aus Heizwerken, die die Rheologie der Mischung verbessert und die Menge an Zement dank seiner latent hydraulischen Eigenschaften verringert. Materialien mit ahnlichen Eigenschaften unter Verwendung von Abfallrohstoffen werden beispielsweise in der Form von Mauerputz verwendet [1–3]. Das Ziel dieser Forschung war es, ein zu dem Bereich der Energiesanierung von Gebauden, der Feuchtigkeitssanierung und der Innendammung gehorendes Material zu entwickeln. Materialien mit diesem Anwendungsbereich mussen die Anforderungen an einen niedrigen Wert des Diffusionswiderstands, einen hohen Wert der Kapillaraktivitat und einen niedrigen Wert der Warmeleitzahl erfullen. Die gemessenen thermischen und technischen Parameter des entwickelten Materials wurden in die numerische Software Delphin ubernommen, um das Feuchteverhalten der strukturellen Verbindungsgelenke im Fensterbau zu simulieren. Die entwickelten Rezepturen wurden weiterhin auf der Grundlage dieser Berechnungen modifiziert, und Platten mit der besten Kombination von thermischen und technischen Variablen wurden verglichen.

The aim of the publication is the comparative measurements of changes in temperature of the significant material coefficient - thermal conductivity for newly developed construction materials (lightweight concrete). The aim is met by using a newly proposed method and a newly developed device by the approximation modelling of the temperature dependence of the thermal conductivity coefficient of the new composites and also the interpretation of measurement results in the context of optimally desired characteristics of thermal insulation concrete. Construction materials for residential buildings should have good thermal insulation properties, i.e. relatively low coefficients of thermal conductivity. With regard to the relatively most important property of concrete – strength, however, the reduction in thermal conductivity of concrete is limited. Thermal conductivity of concrete can be reduced very effectively by increasing its porosity; on the other hand, by increasing the porosity, the strength of concrete is significantly reduced. The publication, therefore, compares the results of temperature dependences of thermal conductivity for three newly designed concretes, namely in the context of their compressive strength.

The paper presents the results of construction waste treatment for possible replacement of natural aggregates in cement composites. The individual processes of construction waste treatment for the purpose of obtaining the required fractions 0/4 mm, 4/8 mm and 8/16 mm are described. It deals with the so-called recycled aggregate, which will subsequently be used in cement composites as a substitute for natural aggregate. The properties of individual fractions of recycled aggregate are presented, both in terms of composition, density, water absorption and granulometric, mineralogical and elemental composition.

Towards the end of the 20th century there was a huge boom in the development of solar energy, which led to an increase in the production of photovoltaic panels. The producers assume a lifetime of these panels of 30 years. Today, the life of this photovoltaic panels is ending and a large amount of waste is associated with it. This issue is also addressed by the Council of the European Union, which issued Directive 2012/19/EU on waste electrical and electronic equipment. Photovoltaic panels are included in IV. category “Consumer electronics and photovoltaic panels”. This Directive mandates that at least 70% of photovoltaic panel materials must be reused or recycled. This paper presents a review of the current trends in recycling of photovoltaic panels and the possibilities of reuse in cement matrix.

This paper presents the results of a research into the use of a combination of recycled rubber from waste tires as a 100% aggregate replacement in the production of cement composites. The aggregate was replaced with rubber recycled material in two ratios. At a ratio of 50/50 and a ratio of 40/60 fraction 0/1 mm and fraction 1/3 mm. The test specimens were further subjected to CO2 effect in a Lamart laboratory chamber, where CO2 effect was simulated as equivalent to an aging period of 50 years. The presented results show that the effect of CO2 reduces the strength characteristics of the composite compared to the comparative samples.

The present article deals with the fungicidal properties of cement composites based on Waste Sludge Water (WSW) from a concrete plant (CP). The article compares the ability of standard cement composites and cement composites based on WSW to withstand microscopic fungi Aspergillus niger, Trichoderma nereus and Penicillium glabrum. The results of the tests show that the use of WSW as a substitute for pure mixing water in the preparation of cement composites does not have a significant positive or negative effect on the fungicidal properties of the prepared composites.

This article presents the results of a research dealing with the detection of mutagenic activity of two samples used in the textile industry, Methylene Blue synthetic dye and Inotex real dye bath before, during and at the end of the biodegradation process by means of ligninolytic fungus Irpex lacteus. There is evidence that Methylene Blue synthetic dye was detected as an indirect mutagen prior to the biodegradation process. However, the biodegradation intermediate product was evaluated as a direct mutagen and the final product of biodegradation no longer induced any mutagenic activity. Inotex dye bath samples were assessed as non-mutagenic.

This publication deals with the migration permeability of watercourses in the Czech Republic and in the world from the point of view of the constructions enabling this migration. The goal of this article is to compare the situation of fish ladders in the individual continents with the situation in the Czech Republic. It is clear that the area of migration permeability of watercourses was only a marginal topic worldwide, but this sphere of water management has recently gained increasing importance.

This article deals with the flood situation in the municipality of Hradec nad Svitavou and describes the possibility of increasing the flooding protection by means of a dry detention basin, whose task is to transform the flood wave thus reducing the damage caused by the wave. This measure will increase the time required to carry out the necessary flood preparations. Dry detention basin is based on hydraulic calculations and drawings described in more details in this article.

This article deals with the proposal of revitalization measures on the Výškovický Stream. The area where the measures are to be executed is heavily transformed by anthropogenic activity. Anthropogenic activity in the area in question consists mainly of deflecting the stream into a prefabricated concrete trough. The actual proposed revitalization measures are based on the use of meanders along the stream route, which will extend the route by 114 meters. 2 pool meanders and 5 pools have been designed along the route.

This article presents the results of a study dealing with the utilization of sludge water from a concrete plant as a partial replacement for mixing water in the production of cement composites. The replacement of mixing water with sludge water from a concrete plant was carried out in the amounts of 20% and 50%. The following tests were carried out in order to determine the effect of the replacement of mixing water with sludge water from a concrete plant on the physical and mechanical properties of the cement composites: cement mortar consistency, beginning and end of setting, strength characteristics (compressive strength and flexural strength), and thermal properties. The measured values of the strength characteristics of the test specimens after 28 days of age confirm the possibility of replacing mixing water with sludge water from a concrete plant without significantly reducing the compressive and flexural strength. Web of Science 7 4 art. no. 120

This article presents the results of an experimental research dealing with the use of steel slag as a partial substitute for natural aggregates in the production of concrete composite. Comparative mixture based on natural aggregates was prepared from the fractions of 0/4, 4/8 and 8/16 mm, which were represented in the volume ratio of 40:30:30. During the experimental research, natural aggregates with the fractions of 4/8 mm, 8/16 mm were replaced with steel slag of the same faction. We have tested the input properties of natural aggregates and steel slag for the designed experimental mixtures (grain size, density, specific weight, powder density, absorption capacity, resistance to crushing, shape index). In case of concrete mixture prepared according to the experimental recipes, we have monitored the following characteristics: density of fresh concrete mixture, consistency of concrete mixture, strength characteristics - cube strength after 3, 7, 14, 21, 28 and 90 days, prism strength after 28 days. The research has discovered that substitution of natural aggregates with steel slag of the same fraction in concrete mixture is possible, without significantly affecting the strength properties of the concrete based on steel slag in comparison with the concrete based on natural aggregates.

This paper proposes the evaluation of material coefficient of heat dissipation rate for building materials, in particular using partial entropies, a temporal change in entropy upon heating a sample of a studied material and a temporal change in entropy upon overheating a sample of a studied material, in order to evaluate the rate of heat dissipation on samples of building materials with thermal insulating properties. From a physical point of view, the material parameter “specific heat capacity” generally refers to the ability of material to “conceive heat” so it can be said that the illustrated material Ytong has a slightly higher specific heat capacity than that of polyurethane. From a physical point of view, the material parameter “thermal conductivity” generally refers to the ability of a given material to “conduct heat through the material in connection with stationary heat flux”, so it can be assumed as well as verified by measuring that Ytong also has a higher thermal conductivity than that of polyurethane. From a physical point of view, the newly proposed material parameter “heat dissipation rate” generally indicates the “rate of heat loss to the external environment in connection with non-stationary heat flux”, so it may also be assumed and verified by measuring that the heat dissipation rate of Ytong will be higher than that of polyurethane.

This article presents the results of an experimental research dealing with the preparation of cement composites with an addition of steel slag, in order to verify the possibility of using ground steel slag as a suitable admixture into cement composites. The samples of the cement composites were prepared with the following types of cements: Portland cement CEM I 42.5 R, Portland mixed cement CEM II/B-S 32.5 R, blast furnace cement CEM III/A 32.5 N, and mixed cement CEM V/A (S-V) 32.5 R. We have tested the effect of ground steel slag as an admixture, which had been dosed in the amount of 20% of the weight of the cement dose, on the strength parameters (tensile flexural strength and compressive strength) and the thermal properties (coefficient of thermal conductivity λ, specific heat capacity c, and coefficient of thermal diffusivity a). The results of this experimental research have shown that the use of ground steel slag as an admixture in an amount of 20% of the weight of cement in the cement composite will reduce the values of the coefficient of thermal conductivity λ in cements CEM I 42.5 R, CEM II/B-S 32.5 R, and CEM V/A (S-V) 32.5 R and, at the same time, it will not cause a decrease in compressive strength.

The article deals with energy rehabilitation of a building with damaged waterproofing of its lower structure. The reference construction is made of fired bricks, whose functional properties are perfectly fine, but the thermal insulation properties are insufficient for this time. The most common solution of such a problem is the application of a thermal insulating material based on expanded polystyrene on the building envelope. Unfortunately, these solutions often entail the risk of moisture problems in places that appeared to be dry before. The article compares the current solution with the new one relying on material based on calcium silicate [4] with high moisture transport capabilities as an alternative insulation of these buildings.

The article describes the results of an experimental research dealing with the use of industrial waste in the form of secondary raw material - polyurethane foam after the end of its life cycle, as a 100% substitute of filler in restoration plaster with thermal insulating effect. The article presents the formulas of restoration plaster and its properties. They are: mortar consistency, volume weight, strength characteristics, thermal conductivity coefficient, coefficient of capillary water absorption, porosity and resistance against salts.

The application of bio-based material such as cellulose fibres derived from renewable source to cement mortars was investigated and the properties of fresh mixtures and hardened mortars were characterized. The mixtures composition consisted of combined addition of the selected kind of cellulose fibres (bleached wood pulp) and superplasticizer (polycarboxylate ester). The aim was to produce a cement mortar with the improved properties for indoor application. The 0.5 wt.% fibre addition (from weight of filler and binder) and superplasticizer dosage of 1% in the mixtures were used. Reference cement mortar did not contain cellulose fibre and superplasticizer. The comparative study of the fresh fibre cement mixture properties has been showed worse flowability behaviour of mixture with plasticizer, as expected. The the beneficial effect of the superplasticizer was not proven even on the compressive and flexural strength of fibre cement mortars after 7, 28 and 90 days of hardening. The performances of the mortars were dependent not only on fibres and superplasticizer nature but also on the organic/inorganic interface.