Publikační činnost Katedry stavebních hmot a diagnostiky staveb / Publications of Department of Building Materials and Diagnostics of Structures (223)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64792

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry stavebních hmot a diagnostiky staveb (223) v časopisech registrovaných ve Web of Science od roku 2003.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Properties of selected alkali-activated materials for sustainable development
(Sciendo, 2024) Němec, Jiří; Gandel, Radoslav; Jeřábek, Jan; Sucharda, Oldřich; Bílek, Vlastimil
Concrete, which is based on the use of Portland cement as a binder, is often used as a structural material in the construction industry. However, the production of cement has a high energy demand. Alkaline-activated systems, for example, have the potential to replace cement with suitable substitutes, and this also puts the raw materials created as by-products from industrial processes to the fore. The presented research focuses on three selected variants, where the goal is to compare key properties from the point of view of material engineering and structural design. Tests of the mechanical properties of the examined materials are carried out and their durability is compared, namely frost resistance, resistance to chemical and de-icing substances and resistance to elevated temperature. As part of the main design criterion of structure, the resulting average compressive strengths of the selected alkali-activated materials ranged from 52.8 to 62.8 MPa.
Mechanical properties of wooden elements with 3D printed reinforcement from polymers and carbon
(MDPI, 2024) Dedek, Jan; Juračka, David; Bujdoš, David; Lehner, Petr
The research presented in this article aimed to investigate the differences in mechanical properties between solid structural timber and the same reinforced element in three different ways. A three-point bending test was performed on wood elements reinforced with carbon-fiber-reinforced polymer (CFRP), 3D printed polycarbonate (3DPC) lamellas, and 3D printed polycarbonate with carbon fiber (3DPCCF) lamellas. In this comparison, the bending strength was large for CFRP samples, which have 8% higher performance than samples with 3DPCCF and 19% higher performance than samples with 3DPC. Conversely, when factoring in theoretical manufacturing costs, the performance of 3DPCCF is almost three times that of CFRP and 3DPC. In addition, 3D materials can be used for more complicated reinforcement shapes than those discussed in the paper.
Experimental measurement of the load-bearing capacity of wire hooks and bends used in gabion retaining walls
(The Geomate International Society, 2023) Čajka, Radim; Burkovič, Kamil; Neuwirthová, Zdeňka; Mynarčík, Petr; Bujdoš, David
Gabion walls are today a very popular and ecological solution for retaining walls in civil engineering. Gabions are made of stones placed in wire baskets made of galvanized wire, which are interconnected by hooks and bends. Their advantage is the natural appearance, good conditions for landscaping and catching climbing plants. Unlike concrete or masonry retaining walls, they cannot have cracks and therefore resist uneven subsidence of the subsoil. However, the decisive factor for their load-bearing capacity is the quality of the quarry stone, its placement and the load-bearing capacity of the individual wires and, above all, their joints. In the laboratories of the Faculty of Civil Engineering of the Technical University of Ostrava, a number of tests of wire basket hook joints were performed, which were taken from damaged gabions on construction sites. The results of these tests will enable better prediction of the static effect of gabion walls in their design and implementation in construction practice. The paper presents the results of these tests and recommendations for their design and planning.
Properties of fine graded perlite-based lightweight cement mortars subjected to elevated temperatures
(MDPI, 2023) Pizoń, Jan; Konečný, Petr; Mynarz, Miroslav; Bílek, Vlastimil
The present research compared the behaviours of lightweight mortars based on ordinary Portland cement (OPC), calcium sulphoaluminate cement (CSAC), and calcium aluminate cement (CAC) containing expanded perlite and subjected to elevated temperatures. The perlite substituted natural sand in amounts of 25, 50, 75, and 100% by volume. The mortars were subjected to heating at up to 300 ◦C, 650 ◦C, and 1000 ◦C at a rate of 20 ◦C/min. The consistency and density of fresh mortars, compressive strength and density of hardened mortars after heating and cooling, and absorbability were assessed. Such a holistic testing approach is the main novelty of this research, which is related to the aforementioned mixtures and elevated temperatures. The main contribution of this article is a comparison of various cement types coupled with variations in the level of sand replacement with expanded perlite. In previous studies, comparisons were made in pairs of OPC-CSAC and OPC-CAC for normal-weight concrete. There is a gap in our knowledge of triple comparisons and lightweight cement composites which is filled by the current study. The use of OPC at up to 650 ◦C is recommended because it is the most common solution, its performance is similar to that of CAC, and it is cheaper than other solutions. Above 650 ◦C and up to 1000 ◦C, CAC is the only solution because it performs better than other cements. CSAC is not suitable for use at elevated temperatures because of its poor strength performance, even if it is the best solution from an environmental point of view. Sand replacement with perlite does not increase the strength performance under elevated temperatures, but its efficiency is different for various types of cement.
The objectivization of the living green walls concept as a tool for urban greening (Case study: LIKO-S a.s., Slavkov u Brna, Czech Republic)
(MDPI, 2023) Brázdová, Adéla; Kupka, Jiří
The improvement of human well-being and the urban environment in cities and towns around the world will always be at the forefront of our interests. After all, the resilience of the urban environment to climate change is very important now. For example, the residents’ well-being can be improved in terms of environmental aspects. The opportunities for improving the urban environment are, of course, closely interconnected with other aspects, i.e., economic, technical and social. One of the ways to increase the resilience of cities is by progressive urban greening with small urban greenery elements. Exterior green walls are attractive, often used in urban areas, and are also the key issue of our paper. They represent at first sight (concerning their usual size) only a small instrument, but they can have a significant environmental, techno-economic and socio-cultural impact. Potential stakeholders may not be aware of this consequence. Our research focuses not only on a model exterior green wall (LIKO-S a.s., Czech Republic), where selected environmental aspects were measured for one year to confirm or deny the cooling effect of the exterior green wall on the surrounding environment, but also to objectify the issue of green walls. We also present proposals for tools that consider other aspects (technical-economic and socio-economic aspects): objectivization-decision scheme and guided interview for stakeholders’ motivation. These tools can serve future stakeholders in the pre-implementation phase of the intended exterior green wall. Objectivization of exterior green walls is the main goal of the present paper.
Microstructure, shrinkage, and mechanical properties of concrete with fibers and experiments of reinforced concrete beams without shear reinforcement
(MDPI, 2022) Sucharda, Oldřich; Marcalíková, Zuzana; Gandel, Radoslav
The current findings on concrete with fibers show that research has focused primarily on individual aspects, especially in terms of mechanical properties and structural uses. However, no broader view of the problems solved has been provided. In this study, we present a conceptual overview of a new, comprehensive experimental program for the assessment of fiber-reinforced concrete, which includes the analysis of microstructural and structural elements, as well as specific features such as shrinkage and resistance to pressurized water. The proposed experimental program included several variants of schemes for the dosing of fibers into concrete, using steel fibers that were short and straight. Fiber dosing was performed up to 110 kg/m(3). The basic tests performed included tests of the compressive strength of concrete, and of the split and flexural tensile strength for different dosing amounts. Within the structural tests of reinforced concrete beams without shear reinforcement, two variants of spans with different degrees of reinforcement were implemented. Herein, the test results are evaluated graphically with a detailed analysis of the positive effect of fibers, and we also provide general recommendations for the structural uses of the fibers used and the design of fiber-reinforced concrete structures. Among the important results of this experimental program was the observation of a significant increase (of the order of tens) of the percentage of the split tensile strength and an increase of the overall load-bearing capacity of the reinforced concrete beams without shear reinforcement. Among the important aspects of our findings is the fact that a fine-grained concrete mixture was used, which increased resistance to pressure water seepage, and therefore, the effect of shrinkage can be influenced by the method of production and the treatment of the concrete used. We also provide detailed figures of the microstructure.
Influence of size and orientation of 3D printed fiber on mechanical properties under bending stress
(Budapesti Muszaki es Gazdasagtudomanyi Egyetem, 2022) Juračka, David; Kawulok, Marek; Bujdoš, David; Krejsa, Martin
The principle of FFF/FDM (Fused Filament Fabrication/Fused Deposition Modeling) 3D printing technology is the melting and application of a continuous fiber made of thermoplastic material, according to predefined routes on the substrate. A layer is created on which other layers are placed until the object is finished. It is the orientation of these fibers that greatly affects the resulting mechanical properties. Therefore, the printed object behaves orthotropic. The material does not blend perfectly or evenly between the individual fibers, which is why the resulting strength is limited by adhesion. Within the fibers themselves, it is also its dimension that affects the size of the contact surface and therefore the effect of adhesion. This contribution aims to compare the effect of fiber size in a given direction and its rotation in 3-point bending according to the standard ??SN EN ISO 178. The maximum bending load force was obtained and the bending stress and modulus of elasticity were determined. The influence of layer cohesion on the failure of the specimens is compared. One of the other important studied aspects for the effective production is the printing time of each specimen.
Assessment of fatigue resistance of concrete: S-N curves to the Paris’ law curves
(Elsevier, 2022) Miarka, Petr; Seitl, Stanislav; Bílek, Vlastimil; Cifuentes, Hector
Fatigue behaviour of concrete materials is often investigated on un-notched specimens under the compressive or bending loads. In this experimental study, a notched three-point bending (TPB) specimen is used in high-cycle fatigue experiments to obtain the Wohler's curve. Based on this approach, a novel, yet relatively simple transition from the traditional Wohler's curve to the Paris' law curve is proposed. Such a methodology allows one to obtain the Paris' law material constants, which are used to determine the fatigue failure of the structure or a component. The constants of the experimentally determined material, measured in four different concrete mixtures, have been verified by recalculating the number of cycles until the fatigue failure Nf by the integration of the Paris' law equation. The back-calculated number of cycles and the approximation of the S-N curve allowed for a comparison with the experimental data. Furthermore, the initial notch tip was extended in this approximation by the value of the critical distance. Such an extension allowed us to cover a wide range of the experimental data and provided a better prediction of fatigue life. The proposed method was verified on all four studied materials and showed satisfactory results.
Timber semirigid frame connection with improved deformation capacity and ductility
(MDPI, 2022) Johanides, Marek; Lokaj, Antonín; Mikolášek, David; Mynarčík, Petr; Dobeš, Pavel; Sucharda, Oldřich
The present study deals with the innovation and the possibilities of improving the design solution of a frame connection for two selected types of fasteners. All specimens were made of glued laminated timber. Dowel-type mechanical fasteners, a combination of bolts and dowels, and full-threaded screws were used for the connection. The main goal of this research was to replace the typical solution (common dowel-type fasteners) with a more modern, faster, and easier solution in order to improve the load-carrying capacity, ductility, and deformation capacity of this type of frame connection. This article also aimed to provide a detailed evaluation of the mechanical properties of the used glued laminated timber and fasteners in order to comprehensively evaluate the research task. For the design solution, a frame connection created from a system of two struts and a partition was chosen as the basis of the experimental program. Dowel-type mechanical fasteners, as well as combinations of bolts and dowels, were used for the connection; however, in addition to these standardly used mechanical fasteners, full-threaded screws were used. The article describes the use of static destructive testing to determine the ductility of the connection, considering different variations in the strengthening of the individual segments of the mentioned connection means. In the first variation, the individual components of the frame were not reinforced in any way. In the second, the crossbar was reinforced with two full-threaded bolts. In the third, the webs and the crossbar were reinforced with two full-threaded bolts. In the article, these ductility values were compared with each other and the procedure was set by the currently valid standard.
Influence of fly ash denitrification on properties of hybrid alkali-activated composites
(MDPI, 2022) Procházka, Lukáš; Boháčová, Jana; Vojvodíková, Barbara
This article deals with the possibility of partial replacement of blast furnace slag (GGBFS) with fly ash after denitrification (FAD) in alkali-activated materials. Physical-mechanical and durability properties were tested, hydration reaction was monitored, and infrared spectroscopy was performed. Results were compared between mixtures prepared with fly ash without denitrification (FA), and also with a mixture based only on GGBFS. The basic result is that hybrid alkali-systems with FAD show similar trends to FA. The significant effect of fly ash is manifested in terms of its resistance to freeze-thaw processes. Reactions in a calorimeter show a slower development of reactions with increasing replacement of GGBFS due to the lower reactivity of the fly ash. Through testing the leaching resistance, a decrease in flexural strength was found. This may be due to the descaling of the main hydration product, C-(A)-S-H gel. After 28 days of maturation, compressive strengths of all monitored mixtures ranged from 96 to 102 MPa. The flexural strengths ranged from 6.8 to 8.0 MPa. After 28 days of maturation, the higher strengths reached mixtures without replacing GGBFS. In terms of resistance to freeze-thaw processes, the largest decrease (almost 20%) of flexural strength was achieved by a mixture with 30% of GGBFS replacement by FA. No fundamental differences were found for the mixtures in the FTIR analysis.
Effect of admixtures on durability and physical-mechanical properties of alkali-activated materials
(MDPI, 2022) Procházka, Lukáš; Boháčová, Jana; Vojvodíková, Barbara
The results of ground granulated blast furnace slag (GGBS) tests in alkali-activated systems show that, with its use, it is possible to produce promising materials with the required properties. Unfortunately, GGBS is becoming a scarce commodity on the market, so the effort is to partially replace its volume in these materials with other secondary materials, while maintaining the original properties. This paper focuses on a comparison of two basic types of mixtures. The first mixture was prepared only from ground granulated blast furnace slag (GGBS) and the second type of mixture was prepared with admixtures, where the admixtures formed a total of 30% (15% of the replacement was fly ash after denitrification-FA, and 15% of the replacement was cement by-pass dust-CBPD). These mixtures were prepared with varying amounts of activator and tested. The experiment monitored the development of strength over time and the influence of different types of aggressive environments on the strength characteristics. Thermal analysis and FTIR were used in the experiment to determine the degradation products. The paper provides an interesting comparison of the resistance results of different composites in aggressive environments and at the same time an evaluation of the behavior of individual mixtures in different types of aggressive environment. After 28 days of maturation, the highest strengths were obtained with mixtures with the lowest doses of activator. The difference in these compressive strengths was around 25% in favor of the mixtures with only GGBS; in the case of flexural strength, this difference was around 23%. The largest decreases in strength were achieved in the XA3 environment. This environment contains the highest concentration of sulfate ions according to the EN 206-1 standard. The decreases in compressive strength were 40-45%, compared to the same old reference series. The surface degraded due to sulfate ions. Calcium sulphate dihydrate was identified by FTIR, thermal analysis and SEM as a degradation product.
Units of military fortification complex as phenomenon elements of the Czech borderlands landscape
(MDPI, 2022) Kupka, Jiří; Brázdová, Adéla; Vodová, Jana
This paper is focused on selected units of casemates with enhanced fortification in the military fortification complex of the Czech borderlands landscape as specific forms of brownfields. They represent a functional system that interacts with surrounding nature, landscape character, and human society. Four approaches were chosen to study the function and potential of selected individual abandoned casemates with enhanced fortification, where each of them corresponds to one of the four landscape layers: genius loci, socio-economic sphere, functional relationship (between human and the landscape), and natural conditions. There is a corresponding research method for each of the landscape layers (guided interview with respondents, data analysis on abandoned casemates with enhanced fortifications as brownfields, analysis of their landscape functions, and zoological survey of interior). The main results could show that abandoned casemates with enhanced fortifications can play important roles in all landscape layers: stories and genius loci, abandoned casemates with enhanced fortification as a special type of military brownfield but also as a semi-natural ecosystem, and the same time as a habitat for invertebrates. The analyses and surveys conducted clearly demonstrate that abandoned casemates with enhanced fortification as units of military fortification complex of the Czech borderlands landscape perform several hidden important functions in the landscape for which they cannot be viewed as brownfields. This hidden functional potential is most likely best described by the concept of hidden singularity, which offers itself for integration into basic approaches to brownfields.
Mechanical, thermal, and fire properties of composite materials based on gypsum and PCM
(MDPI, 2022) Stejskalová, Kateřina; Bujdoš, David; Procházka, Lukáš; Smetana, Bedřich; Zlá, Simona; Teslík, Jiří
One of the solutions for overheating the interior in the summer without increasing energy consumption is the integration of phase change material (PCM) into interior plasters. However, adding PCM to plasters deteriorates their properties and thus their usability. The aim of this paper is to determine how the microencapsulated PCM affects the mechanical, thermal, and fire properties of plasters and how much PCM can be added to the plaster. Two sets of samples were prepared: in set S, part of the aggregate was replaced by PCM; and in set R, only PCM was added. The bulk density, flexural strength, compressive strength, tensile strength perpendicular to the surface, thermal conductivity coefficient, specific heat capacity, melting, and solidification temperatures and enthalpy were measured. A single-flame source fire test and a gross heat of combustion fire test were performed to determine the reaction to the fire class. The results show that with an increasing proportion of PCM, the strength of the samples of set R decreased more significantly than it did with the samples of set S. It was found that only up to about 10% PCM could be added to set R, while up to 30% PCM could be added to set S.
Analysis of fiber-reinforced concrete slabs under centric and eccentric load
(MDPI, 2021) Marcalíková, Zuzana; Bílek, Vlastimil; Sucharda, Oldřich; Čajka, Radim
Research on the interaction between slabs and subsoil involves the field of materials engineering, concrete structures, and geotechnics. In the vast majority of cases, research focuses on only one of these areas, whereas for advanced study and computer simulations, detailed knowledge of the whole task is required. Among the new knowledge and information upon which this article focuses is the evaluation of subsoil stress using specialized pressure cells, along with detailed measurements of the deformation of a fiber-reinforced concrete slab. From a design point of view, this research is focused on the issue of the center of the cross section and the influence of eccentricity. Knowledge in this area is not yet comprehensively available for fiber-reinforced concrete slabs, where 2D deformation sections of the slab and 3D deformation surfaces of the slab are used in experiments. The experimental program includes a centrically and eccentrically loaded slab. These are structural elements that were tested on a specialized device. Both slabs had the same concrete recipe, with a dispersed reinforcement content of 25 kg/m(3). The dimensions of the slab were 2000 x 2000 x 150 mm. Laboratory tests assessed compressive strength, the modulus of elasticity, splitting tensile strength, and bending tensile strength. Based on approximate data from the 3D deformation surfaces, an evaluation of the load-displacement diagrams for the center of the slab and for the center of eccentricity was performed. In conclusion, an overall evaluation and discussion of the results relies on experiments and the mechanical properties of fiber-reinforced concrete.
Rotational stiffness and carrying capacity of timber frame corners with dowel type connections
(MDPI, 2021) Johanides, Marek; Mikolášek, David; Lokaj, Antonín; Mynarčík, Petr; Marcalíková, Zuzana; Sucharda, Oldřich
With the development of wooden structures and buildings, there is a need to research physical and numerical tests of wood-based structures. The presented research is focused on construction and computational approaches for new types of joints to use in wooden structures, particularly glued lamella elements made of wood and wood-based composites. This article focuses on improving the frame connection of a wooden post and a beam with the use of fasteners to ensure better load-bearing capacity and stiffness of the structure. In common practice, bolts or a combination of bolts and pins are used for this type of connection. The aim is to replace these commonly used fasteners with modern ones, namely full thread screws. The aim is also to shorten and simplify the assembly time in order to improve the load-bearing capacity and rigidity of this type of frame connection. Two variations of the experimental test were tested in this research. The first contained bolts and pins as connecting means and the second contained the connecting means of a full threaded screw. Each experiment contained a total of two tests. For a detailed study of the problem, we used a 2D or 3D computational model that models individual components, including fasteners.
Physical tests of alternative connections of different high roof purlins regarding upward loading
(MDPI, 2021) Rosmanit, Miroslav; Pařenica, Přemysl; Sucharda, Oldřich; Lehner, Petr
Thin-walled cold-rolled sections are used in the construction industry, especially in the roofing of large-span halls. The load-bearing capacity of a thin-walled structure depends to a large extent on the load-bearing capacity of the details at the point of attachment to the structure and the interconnection of the individual thin-walled elements. Therefore, in the case of thin-walled structures, it is necessary to use additional structural elements such as local reinforcement, stabilising elements, supports, and other structural measures such as the doubling of profiles. This paper focused on the behaviour of tall Z300 and Z350 mm thin-walled trusses at the connection to the superstructure regarding upward loading (e.g., wind suction and so on). Two section thicknesses, 1.89 mm and 2.85 mm, were experimentally analysed. Furthermore, two types of connections were prepared, more precisely without and with a reinforced buckle. The experiments aimed to investigate the behaviour and load-carrying capacity of the detail of the roof truss connections to the supporting structure. The resulting load capacity values were compared with normative approaches. Analyses of the details of the bolt in the connection are also presented. The paper presents a practical evaluation of the physical test on real structural members.
Possibilities of application cement by-pass dust into the garden architecture elements
(MDPI, 2021) Procházka, Lukáš; Vojvodíková, Barbara; Boháčová, Jana
This article deals with the possibility of using cement by-pass dust (CBPD) in the garden architecture elements, specifically in curbs for park use. To increase the positive effect on the environment, other secondary raw materials were also used in the research, specifically blast furnace granulated slag and silica fly ash. Mixtures were based on alkali activation, where cement as a binder was 100% replaced by raw materials with waste properties. In the research, properties of used materials and also the basic physical-mechanical and durability properties of prepared mixtures were determined Part of the research focused on the effect of the tested beams on the grassland planted around the beams. Any significant negative impact was not registered, except for low pH increase of soil. Infrared spectroscopy and thermal analysis were performed on selected samples. Testing has shown that the products are in accordance with the Czech standard requirements for concrete curbs in garden architecture. The samples did not pass only the scaling test, which is, however, a condition for concrete curbs used for roads. For garden architecture this test is not required.
X-ray diffraction of alkali-activated materials with cement by-pass dust
(MDPI, 2021) Vojvodíková, Barbara; Procházka, Lukáš; Boháčová, Jana
Alkali-activated materials are alternative building binders, where secondary raw materials are processed. The possibility of using landfilled waste materials in the building industry increases their potential application in construction practice, and they are therefore subject to extensive research, especially in recent years. This paper briefly summarizes the interesting results of an experiment aimed at verifying the possibility of applying cement by-pass dust (CBPD) in the preparation of alkali-activated materials. The research was focused on the possibilities of using these wastes for the preparation of small elements of garden architecture. This work also briefly summarized the interesting results of an experiment aimed at verifying the possibility of applying cement by-pass dust (CBPD) in the preparation of alkali-activated materials. In the experiment, a mixture of blast furnace granulated slag, fly ash and cement by-pass dust was alkali activated with sodium metasilicate.
Fiber-optic Bragg system for the dynamic weighing of municipal waste: A pilot study
(IEEE, 2021) Fajkus, Marcel; Nedoma, Jan; Martinek, Radek; Danys, Lukáš; Fridrich, Michael; Mec, Pavel; Žabka, Stanislav
The publication focus on a pilot study (design, implementation and verification) of a dynamic weighing system designed for weighing of municipal waste during the dumping of garbage containers. The presented solution is based on fiber Bragg gratings (FBG) and can be additionally implemented into the lifting equipment of commonly employed garbage trucks. The weighing principle is based on the measurement of deformation effect and vibration response of the lifting equipment during the dumping of garbage bins. The measuring system leverages the advantages of power measurement, which use the conversion of the spectral shift of modulated light signal during the measurement to the change in optical power of a pair of spectral overlapping Bragg gratings. Two different methods are presented and discussed: the amplitude method, which analyze the maximum amplitude change of the signal and/or the method, which analyze the time period of the dampened oscillation of the lifting device. Due to the small dimensions, the complete system can be installed together with FBG sensors directly onto the lifting device. The pilot tests of the presented system were carried out for over 4 months, showing an accuracy of up to +/- 4.04 kg in the range of 10-100 kg for standardized containers used for municipal waste. The system worked in completely standalone mode and the garbage trucks were not modified in any inconvenient way.
Research into the influence of subsoil on sulphates, nitrates and chlorides accumulated in renovation plasters used for rehabilitation of monuments in the Czech Republic
(Elsevier, 2021) Peřinková, Martina; Dlábiková, Ivona; Pospíšil, Pavel; Bílek, Vlastimil
Degradation of historical masonry and plasters is often caused by external conditions; the presented research focused on salts originating from subsoils. The content of salts: Sulphates, Nitrates and Chlorides was analysed from plasters on 5 chosen historic buildings before and after the renovation in this paper. The samples were collected three times between 1998-2018. In some cases, the Sulphates were still present or even with a higher content after the renovation in comparison with the state before renovation. That can be caused by many factors from environment and this work focused on source from the subsoil. To understand better geological background the borehole data around each object were studied. According boreholes were buildings divided in two groups: on clayey subsoil and building on subsoil without clay. By Kruskal-Wallis test was proved, that the Sulphates content in plasters was constant before and after the renovation on clayey subsoils, it didnt ' changed in a time. On subsoils without clay (mainly silty to sandy soils) the content of Sulphates declined after the renovation, what was proved by regression analyse on 95% confidence level.

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