Jerzy Hoła - Academia.edu (original) (raw)
Papers by Jerzy Hoła
Budownictwo i Architektura, 2018
W artykule przedstawiono wybrane, ale zdaniem autora, istotne problemy dotyczące postępującej deg... more W artykule przedstawiono wybrane, ale zdaniem autora, istotne problemy dotyczące postępującej degradacji budynków zabytkowych wskutek nadmiernego zawilgocenia. Naświetlono najważniejsze przyczyny i skutki nadmiernego zawilgocenia i zasolenia. Mówiąc o skutkach wskazano między innymi na obniżenie bezpieczeństwa konstrukcji, zmniejszenie izolacyjności cieplnej przegród zewnętrznych oraz na pogorszenie warunków eksploatacyj-nych w pomieszczeniach. Omówiono uwarunkowania badania wilgotności metodami nieniszczącymi wraz ze wskazaniem użytecznych metod w budynkach zabytkowych, zasygnalizowano możliwości wykorzystania do wiarygodnej oceny wilgotności sztucznych sieci neuronowych. Sygnalnie sprecyzowano w ujęciu chronologicznym działania, które należy podejmować w celu zapobieżenia postępującej degradacji budynków zabytkowych powodowanej nadmiernym zawilgoceniem i zasoleniem.
Procedia Engineering, 2017
Microstructural analysis of self-compacting concrete modified with the addition of nanoparticles ... more Microstructural analysis of self-compacting concrete modified with the addition of nanoparticles was carried out. Investigations included SCC concretes modified with different amounts of SiO2, TiO2 and Al2O3 nanoparticle additives and one reference concrete made without nanoparticles. Porosity, maximal pore dimensions, microstructure 3-D models, hardness and elastic modulus were determined. Based on the conducted studies, it can be concluded that the addition of nanoparticles improves the microstructure of self-compacting concrete. It is confirmed both by the results of porosity of the tested samples and by the results of hardness and elastic modulus of the cement matrix of investigated concretes.
Procedia Engineering, 2015
The influence of an additive in the form of selected nanoparticles on the physical and mechanical... more The influence of an additive in the form of selected nanoparticles on the physical and mechanical characteristics of self-compacting concrete a, * b a
Applied Sciences
The progressive development of civil engineering has forced scientists to improve the known metho... more The progressive development of civil engineering has forced scientists to improve the known methods and techniques of testing building materials, and also to search for new ones, e.g., non-destructive testing (NDT) methods [...]
In recent years intensive development of the Non-Destructive Testing (NDT) techniques as applied ... more In recent years intensive development of the Non-Destructive Testing (NDT) techniques as applied to the assessment of the condition of transport infrastructure concrete structures (bridges, roads, railways, tunnels, etc.) has been observed. In this paper, classifications of the techniques, based on various criteria, are proposed and discussed. Special attention is paid to advanced acoustic techniques as applied to the identification of delaminated areas, the detection of internal material defects, the discovery of crack parameters and the precise measurement of structural element thickness, the location of reinforcement, prestressing wires, etc. This paper focuses on ultrasonic tomography, the impulse-response technique and the impact-echo technique. The techniques are illustrated with practical examples, including descriptions of the equipment, the testing procedures, the data acquisition and recording systems, and the numerical data processing procedures based on comprehensive alg...
Proceedings of the Creative Construction Conference 2019, 2019
In construction practice, concrete elements are exposed to adverse environmental influences, and ... more In construction practice, concrete elements are exposed to adverse environmental influences, and therefore sooner or later require repair. This repair is usually performed by removing the damaged concrete and replacing it with repair overlay. The quality of this repair is evaluated using the destructive pull-off method. In this method, the pull-off adhesion value between the repair overlay and repaired element is measured (fb). Unfortunately, the disadvantage of this method is local damage of the element at every measuring point. It is therefore reasonable to present a reliable nondestructive method of identifying the interlayer pull-off adhesion value. The article presents the results of experimental research, which indicate that such identification is possible using complementary nondestructive methods and an artificial neural network with principal component analysis.
This paper presents the possibilities of investigating the morphology of concrete surfaces by mea... more This paper presents the possibilities of investigating the morphology of concrete surfaces by means of a novel 3D laser scanner and the advantages of the latter over the previous scanners. The results of such investigations for differently prepared surfaces on elements made of concretes differing in their composition are compared. The results have the form of three-dimensional images and several surface morphology parameters acquirable using this technique. Unlike the commonly used scanners, which scan the entire surface of an investigated element, the novel 3D scanner is used to precisely analyze the morphology of a 50 × 50 mm surface for the purposes of the nondestructive identification of the pull-off adhesion of concrete layers in layered building elements.
The paper presents ultrasonic tests of cement floors that were carried out in order to show how b... more The paper presents ultrasonic tests of cement floors that were carried out in order to show how big the heterogeneity of the compressive strength distribution along their thickness can be. The tested specimens were taken from floors that had a significantly large surface area, were made of good quality mortar produced on an industrial scale and were of various thicknesses. Special exponential heads with point contact with the specimen's surface were used for the tests. The correlative dependency between the velocity of the longitudinal ultrasonic wave and the compressive strength of mortars embedded in the tested floors was established. It was shown that the heterogeneity of the distribution of this strength along the thickness of the floors is significantly large. In the top zone, which is subjected to direct operational impacts, the compressive strength is definitely lower than that in the bottom and middle zones. The paper points out that this problem should not be underestim...
Proceedings of the Creative Construction Conference 2019, 2019
One of the new directions in self-compacting concrete (SCC) research is the modification of its c... more One of the new directions in self-compacting concrete (SCC) research is the modification of its composition with the addition of nanoparticles, which due to their unique properties are believed to improve the mechanical properties of cementitious composites. An important issue concerning the mechanical behavior of concrete under compression load is the failure process. At the moment, however, there is no knowledge of the effect of nanoparticles on the failure process of compressed SCC. The aim of the work is to investigate the failure process of compressed self-compacting concrete based on coarse and fine granite aggregate made both without and with SiO2 nanoparticles in the amount of 2.0% and 4.0% of the cement weight. The research includes the determination of the levels of the initial cracking stresses σi and the critical stresses σcr that delimit individual stages of the studied process. Investigations were carried out using the acoustic emission (AE) method, and during the tests the recorded descriptors were the sum of counts (Nc) and the average effective value of the acoustic emission signal (RMS). The paper shows that the addition of SiO2 nanoparticles has a positive effect on the failure process of compressed SCC. Moreover, the practical aspect of the obtained results for engineering purposes is provided.
The supply of air to mine shafts performs a vital function in the mining industry. Air is supplie... more The supply of air to mine shafts performs a vital function in the mining industry. Air is supplied through ventilating ducts with fans installed inside them. The walls of the ducts are made of concrete on which a concrete screed is laid. When there is no bond between the two layers, loose pieces of screed are torn off the base concrete by the strong air stream mechanically induced by the operation of the fans, posing a danger to the workers and the equipment. For these reasons the ventilating ducts should be periodically checked. In the authors’ opinion, the nondestructive methods of ultrasonic tomography and impact-echo can be useful for this purpose, which is demonstrated in this paper.
W pracy przedstawiono mozliwości nieniszczącego badania morfologii powierzchni podkladow betonowy... more W pracy przedstawiono mozliwości nieniszczącego badania morfologii powierzchni podkladow betonowych przy wykorzystaniu skanera laserowego 3D o nowej konstrukcji. Przedstawione zostaną tez w ukladzie porownawczym wyniki badan dla powierzchni rozniących sie sposobami przygotowania na podkladach wykonanych z betonow rozniących sie skladem. Zostaną one przedstawione w postaci trojwymiarowych obrazow oraz wielu mozliwych do uzyskania tą metodą parametrow opisujących morfologie. Abstract This article presents the possibility of non-destructive testing of morphology of concrete substrates surfaces by means of newly designed 3D laser scanner. The results of the investigation of differently prepared surfaces will be presented and compared for substrates made out of different mixture of components. The results will be presented as three-dimensional images, and the table of morphology parameters achieved with this method.
12th International Conference on Structural Analysis of Historical Constructions, 2021
The paper presents fragments of original archival documentation, which are used to identify the h... more The paper presents fragments of original archival documentation, which are used to identify the historical outline of the colonnade building and the peristyle pavilion located on Partisan Hill in an old part of Wroclaw. Traces of these buildings date back to the Middle Ages. The state of preservation of these objects was presented on the basis of conducted assessments, drilling cores, and non-destructive and semi-non-destructive tests. Much attention was devoted to the brick walls, brick and reinforced concrete ceilings in flat roofs, as well as to the elements of architectural detail. The presented results include tests of the moisture content and salinity of walls, tests of the compressive strength of concrete and distribution of reinforcement in ceilings. They constitute the first stage of activities that aim to restore the buildings to their former glory.
This paper presents the results of nondestructive tests of concrete inhomogeneity in a massive wa... more This paper presents the results of nondestructive tests of concrete inhomogeneity in a massive wall of a communication gallery in a hydroelectric power plant located on one of the largest rivers in Poland. The tests were carried out using the ultrasonic tomography method. An analysis of the test results showed that in most of the selected measuring places the quality of the concrete is satisfactory. Concrete inhomogeneity, probably in the form of large air voids which had formed as a result of improper concrete compaction or because large aggregate particles had not been properly enveloped in concrete, was detected in only a few places. In such places the microstructure of concrete is inhomogeneous and loose, whereby they are susceptible to water leaks through the wall. The investigations have shown that the ultrasonic tomography method can be successfully used for this purpose. It enables one to quickly detect concrete zones with a different degree of compaction and larger air void...
This paper deals with the modern nondestructive elastic-wave testing of concrete in foundation sl... more This paper deals with the modern nondestructive elastic-wave testing of concrete in foundation slab of building put under the ground water level. The reason for the tests was assumption that the contractor make thin the foundation slab than the design and after that the slab was damage. The tests were carried out to check the thickness of slab according to the design, and to assess the technical condition of the foundation slab to take a decision about the range of repairs to be done to or about their strengthening. The Ultrasonic Tomography technique and ultrasonic, electric and electromagnetic techniques (in a support role) were used in the tests. The nondestructive test results and the analyses carried out on their basis, corroborated by exposures, have not been published before.
123 Faculty of Civil Engineering, Wroclaw University o f Technology, Wybrzeze Wyspianskiego 27, 5... more 123 Faculty of Civil Engineering, Wroclaw University o f Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw e-mail: adelajda.pala@pwr.edu.pl, jerzy.hola@pwr.edu.pl, lukasz.sadowski@pwr.edu.pl (corresponding author) Abstract: In the following article the use of the artificial neural network (ANN) for the non-destructive identi fication of the moisture content of saline ceramic bricks has been pr sented. ANN is taught and tested on a database f ormulated on the basis of experimental tests carried out with the use of non-destructive (NDT) dielectric, resis tive and microwave methods. The tests were performed on soli d clay bricks placed respectively in aqueous nitrat e, chloride and sulphate environments and also in an a quatic environment without salts as a comparison. A s a result of the carried out research and analysis it was pro ved that reliable non-destructive identification of the moisture content in saline ceramic bricks based on the param eters evaluated with the above-men...
Energies, 2021
The article deals with the problem of detecting moisture in the walls of historical buildings. As... more The article deals with the problem of detecting moisture in the walls of historical buildings. As part of the presented research, the following four methods based on mathematical modeling and machine learning were compared: total variation, least-angle regression, elastic net, and artificial neural networks. Based on the simulation data, the systems for the reconstruction of “pixel by pixel” tomographic images were trained. In order to test the reconstructive algorithms obtained during the research, images were generated based on real measurements and simulation cases. The method comparison was performed on the basis of three indicators: mean square error, relative image error, and image correlation coefficient. The above indicators were applied to four selected variants that corresponded to various parts of the walls. The variants differed in the dimensions of the tested wall sections, the number of electrodes used, and the resolution of the 3D image meshes. In all analyzed variant...
Materials, 2020
The article presents original complex methodology for the effective control of the entire process... more The article presents original complex methodology for the effective control of the entire process of executing floors made of cement-based materials. This methodology has been lacking in literature so far. The methodology was developed on the basis of many years of the authors’ experience, which was acquired when diagnosing the technical condition of such floors. The methodology was preceded by a synthetic summary of the most important technological and technical requirements for floors made of cement-based materials. It was also enriched with a discussion of the problem documented by sample research results showing the state that may be the result of disregarding and not performing the necessary control activities.
Automation in Construction, 2020
Taking into consideration the wide use of self-compacting concrete in engineering practice and th... more Taking into consideration the wide use of self-compacting concrete in engineering practice and the need to better understand its mechanical work, while at the same time attempting to use additives with a smaller grain size as a component of concrete, the paper presents the results of the authors' own research, conducted using the acoustic emission method, on the failure process of self-compacting compressed concrete both with and without the addition of 2.0% and 4.0% of SiO 2 and TiO 2 nanoparticles with regards to cement weight. The levels of crack initiation stresses σ i and critical stresses σ cr , which distinguish the individual stages of the investigated process, were determined. The obtained results were used to calculate the fatigue strength of all the concretes that were tested in the paper. Based on the achieved results, it can be concluded that the durability and safety of structures made of self-compacting concrete with the addition of SiO 2 and TiO 2 nanoparticles that are subjected to repeatedly variable loads will be higher when compared to structures made of concrete without these additives.
Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo, 2018
Trwałość zarówno warstwowych elementów betonowych, takich jak podłogi, jak i elementów betonowych... more Trwałość zarówno warstwowych elementów betonowych, takich jak podłogi, jak i elementów betonowych skorodowanych powierzchniowo i naprawionych poprzez nałożenie warstwy betonu naprawczego, istotnie zależy od należytego zespolenia warstw [1]. To należyte zespolenie zdefiniowane jest normowo [2] w rozumieniu żądanej minimalnej wartości przyczepności międzywarstwowej. Warto w tym miejscu powiedzieć, że zjawiska fizykochemiczne występujące na granicy dwóch stykających się materiałów, prowadzące do ich wzajemnego zespolenia, nazywane są przyczepnością-adhezją (łac. "adhaesio"-szczepienie). Wyróżnia się adhezję właściwą (specyficzną), związaną z oddziaływaniami chemicznymi i fizykochemicznymi, oraz adhezję mechaniczną, związaną z mechanicznym zakotwieniem materiału warstwy wierzchniej w porach i nierównościach materiału warstwy podkładowej [3-7]. Makroskopową miarą zespolenia betonu warstwy wierzchniej z betonem warstwy podkładowej (spodniej) jest wartość przyczepności przy odrywaniu f b , określana w praktyce niszczącą metodą odrywania na podstawie pomiaru wartości siły odrywającej za pomocą specjalnego siłownika [2]. Im wyższa jest wartość f b , tym zespolenie uznaje się za lepsze. Na podstawie tych badań można uzyskać "mapę przyczepności", na przykład na użytek zgrubnej lokalizacji rejonów wadliwych. Na podstawie tych badań można także ocenić, czy oderwanie nastąpiło na styku warstw (zniszczenie adhezyjne) czy w materiale warstwy wierzchniej lub podkładowej (zniszczenie kohezyjne), jednak bez uzyskania odpowiedzi na pytanie, dlaczego tak się stało. Oceny zespolenia warstw betonowych w skali makro można też dokonać przy wykorzystaniu do tego celu metody młoteczkowej, metody odpowiedzi na impuls A problem of a multi-scale approach of the assessment of interlayer bond between concrete layers
Structure and Environment, 2018
The paper presents the problems concerning the principles of developing expertise and performing ... more The paper presents the problems concerning the principles of developing expertise and performing tests on reinforced concrete structures. The situations that justify the need to provide expertise, the subject of which are constructions made of reinforced concrete, are described. A layout of the content of expertise that is usually adopted in practice has been included and commented on. The basic principles that should be followed when diagnosing the structures in question are provided. The available diagnostic methods and techniques, including non-destructive and semi non-destructive ones, are reviewed. This review is enriched with classifications that facilitate the selection of specific methods for individual diagnostic needs. In addition, useful literature with regards to the discussed topic has been indicated.
Budownictwo i Architektura, 2018
W artykule przedstawiono wybrane, ale zdaniem autora, istotne problemy dotyczące postępującej deg... more W artykule przedstawiono wybrane, ale zdaniem autora, istotne problemy dotyczące postępującej degradacji budynków zabytkowych wskutek nadmiernego zawilgocenia. Naświetlono najważniejsze przyczyny i skutki nadmiernego zawilgocenia i zasolenia. Mówiąc o skutkach wskazano między innymi na obniżenie bezpieczeństwa konstrukcji, zmniejszenie izolacyjności cieplnej przegród zewnętrznych oraz na pogorszenie warunków eksploatacyj-nych w pomieszczeniach. Omówiono uwarunkowania badania wilgotności metodami nieniszczącymi wraz ze wskazaniem użytecznych metod w budynkach zabytkowych, zasygnalizowano możliwości wykorzystania do wiarygodnej oceny wilgotności sztucznych sieci neuronowych. Sygnalnie sprecyzowano w ujęciu chronologicznym działania, które należy podejmować w celu zapobieżenia postępującej degradacji budynków zabytkowych powodowanej nadmiernym zawilgoceniem i zasoleniem.
Procedia Engineering, 2017
Microstructural analysis of self-compacting concrete modified with the addition of nanoparticles ... more Microstructural analysis of self-compacting concrete modified with the addition of nanoparticles was carried out. Investigations included SCC concretes modified with different amounts of SiO2, TiO2 and Al2O3 nanoparticle additives and one reference concrete made without nanoparticles. Porosity, maximal pore dimensions, microstructure 3-D models, hardness and elastic modulus were determined. Based on the conducted studies, it can be concluded that the addition of nanoparticles improves the microstructure of self-compacting concrete. It is confirmed both by the results of porosity of the tested samples and by the results of hardness and elastic modulus of the cement matrix of investigated concretes.
Procedia Engineering, 2015
The influence of an additive in the form of selected nanoparticles on the physical and mechanical... more The influence of an additive in the form of selected nanoparticles on the physical and mechanical characteristics of self-compacting concrete a, * b a
Applied Sciences
The progressive development of civil engineering has forced scientists to improve the known metho... more The progressive development of civil engineering has forced scientists to improve the known methods and techniques of testing building materials, and also to search for new ones, e.g., non-destructive testing (NDT) methods [...]
In recent years intensive development of the Non-Destructive Testing (NDT) techniques as applied ... more In recent years intensive development of the Non-Destructive Testing (NDT) techniques as applied to the assessment of the condition of transport infrastructure concrete structures (bridges, roads, railways, tunnels, etc.) has been observed. In this paper, classifications of the techniques, based on various criteria, are proposed and discussed. Special attention is paid to advanced acoustic techniques as applied to the identification of delaminated areas, the detection of internal material defects, the discovery of crack parameters and the precise measurement of structural element thickness, the location of reinforcement, prestressing wires, etc. This paper focuses on ultrasonic tomography, the impulse-response technique and the impact-echo technique. The techniques are illustrated with practical examples, including descriptions of the equipment, the testing procedures, the data acquisition and recording systems, and the numerical data processing procedures based on comprehensive alg...
Proceedings of the Creative Construction Conference 2019, 2019
In construction practice, concrete elements are exposed to adverse environmental influences, and ... more In construction practice, concrete elements are exposed to adverse environmental influences, and therefore sooner or later require repair. This repair is usually performed by removing the damaged concrete and replacing it with repair overlay. The quality of this repair is evaluated using the destructive pull-off method. In this method, the pull-off adhesion value between the repair overlay and repaired element is measured (fb). Unfortunately, the disadvantage of this method is local damage of the element at every measuring point. It is therefore reasonable to present a reliable nondestructive method of identifying the interlayer pull-off adhesion value. The article presents the results of experimental research, which indicate that such identification is possible using complementary nondestructive methods and an artificial neural network with principal component analysis.
This paper presents the possibilities of investigating the morphology of concrete surfaces by mea... more This paper presents the possibilities of investigating the morphology of concrete surfaces by means of a novel 3D laser scanner and the advantages of the latter over the previous scanners. The results of such investigations for differently prepared surfaces on elements made of concretes differing in their composition are compared. The results have the form of three-dimensional images and several surface morphology parameters acquirable using this technique. Unlike the commonly used scanners, which scan the entire surface of an investigated element, the novel 3D scanner is used to precisely analyze the morphology of a 50 × 50 mm surface for the purposes of the nondestructive identification of the pull-off adhesion of concrete layers in layered building elements.
The paper presents ultrasonic tests of cement floors that were carried out in order to show how b... more The paper presents ultrasonic tests of cement floors that were carried out in order to show how big the heterogeneity of the compressive strength distribution along their thickness can be. The tested specimens were taken from floors that had a significantly large surface area, were made of good quality mortar produced on an industrial scale and were of various thicknesses. Special exponential heads with point contact with the specimen's surface were used for the tests. The correlative dependency between the velocity of the longitudinal ultrasonic wave and the compressive strength of mortars embedded in the tested floors was established. It was shown that the heterogeneity of the distribution of this strength along the thickness of the floors is significantly large. In the top zone, which is subjected to direct operational impacts, the compressive strength is definitely lower than that in the bottom and middle zones. The paper points out that this problem should not be underestim...
Proceedings of the Creative Construction Conference 2019, 2019
One of the new directions in self-compacting concrete (SCC) research is the modification of its c... more One of the new directions in self-compacting concrete (SCC) research is the modification of its composition with the addition of nanoparticles, which due to their unique properties are believed to improve the mechanical properties of cementitious composites. An important issue concerning the mechanical behavior of concrete under compression load is the failure process. At the moment, however, there is no knowledge of the effect of nanoparticles on the failure process of compressed SCC. The aim of the work is to investigate the failure process of compressed self-compacting concrete based on coarse and fine granite aggregate made both without and with SiO2 nanoparticles in the amount of 2.0% and 4.0% of the cement weight. The research includes the determination of the levels of the initial cracking stresses σi and the critical stresses σcr that delimit individual stages of the studied process. Investigations were carried out using the acoustic emission (AE) method, and during the tests the recorded descriptors were the sum of counts (Nc) and the average effective value of the acoustic emission signal (RMS). The paper shows that the addition of SiO2 nanoparticles has a positive effect on the failure process of compressed SCC. Moreover, the practical aspect of the obtained results for engineering purposes is provided.
The supply of air to mine shafts performs a vital function in the mining industry. Air is supplie... more The supply of air to mine shafts performs a vital function in the mining industry. Air is supplied through ventilating ducts with fans installed inside them. The walls of the ducts are made of concrete on which a concrete screed is laid. When there is no bond between the two layers, loose pieces of screed are torn off the base concrete by the strong air stream mechanically induced by the operation of the fans, posing a danger to the workers and the equipment. For these reasons the ventilating ducts should be periodically checked. In the authors’ opinion, the nondestructive methods of ultrasonic tomography and impact-echo can be useful for this purpose, which is demonstrated in this paper.
W pracy przedstawiono mozliwości nieniszczącego badania morfologii powierzchni podkladow betonowy... more W pracy przedstawiono mozliwości nieniszczącego badania morfologii powierzchni podkladow betonowych przy wykorzystaniu skanera laserowego 3D o nowej konstrukcji. Przedstawione zostaną tez w ukladzie porownawczym wyniki badan dla powierzchni rozniących sie sposobami przygotowania na podkladach wykonanych z betonow rozniących sie skladem. Zostaną one przedstawione w postaci trojwymiarowych obrazow oraz wielu mozliwych do uzyskania tą metodą parametrow opisujących morfologie. Abstract This article presents the possibility of non-destructive testing of morphology of concrete substrates surfaces by means of newly designed 3D laser scanner. The results of the investigation of differently prepared surfaces will be presented and compared for substrates made out of different mixture of components. The results will be presented as three-dimensional images, and the table of morphology parameters achieved with this method.
12th International Conference on Structural Analysis of Historical Constructions, 2021
The paper presents fragments of original archival documentation, which are used to identify the h... more The paper presents fragments of original archival documentation, which are used to identify the historical outline of the colonnade building and the peristyle pavilion located on Partisan Hill in an old part of Wroclaw. Traces of these buildings date back to the Middle Ages. The state of preservation of these objects was presented on the basis of conducted assessments, drilling cores, and non-destructive and semi-non-destructive tests. Much attention was devoted to the brick walls, brick and reinforced concrete ceilings in flat roofs, as well as to the elements of architectural detail. The presented results include tests of the moisture content and salinity of walls, tests of the compressive strength of concrete and distribution of reinforcement in ceilings. They constitute the first stage of activities that aim to restore the buildings to their former glory.
This paper presents the results of nondestructive tests of concrete inhomogeneity in a massive wa... more This paper presents the results of nondestructive tests of concrete inhomogeneity in a massive wall of a communication gallery in a hydroelectric power plant located on one of the largest rivers in Poland. The tests were carried out using the ultrasonic tomography method. An analysis of the test results showed that in most of the selected measuring places the quality of the concrete is satisfactory. Concrete inhomogeneity, probably in the form of large air voids which had formed as a result of improper concrete compaction or because large aggregate particles had not been properly enveloped in concrete, was detected in only a few places. In such places the microstructure of concrete is inhomogeneous and loose, whereby they are susceptible to water leaks through the wall. The investigations have shown that the ultrasonic tomography method can be successfully used for this purpose. It enables one to quickly detect concrete zones with a different degree of compaction and larger air void...
This paper deals with the modern nondestructive elastic-wave testing of concrete in foundation sl... more This paper deals with the modern nondestructive elastic-wave testing of concrete in foundation slab of building put under the ground water level. The reason for the tests was assumption that the contractor make thin the foundation slab than the design and after that the slab was damage. The tests were carried out to check the thickness of slab according to the design, and to assess the technical condition of the foundation slab to take a decision about the range of repairs to be done to or about their strengthening. The Ultrasonic Tomography technique and ultrasonic, electric and electromagnetic techniques (in a support role) were used in the tests. The nondestructive test results and the analyses carried out on their basis, corroborated by exposures, have not been published before.
123 Faculty of Civil Engineering, Wroclaw University o f Technology, Wybrzeze Wyspianskiego 27, 5... more 123 Faculty of Civil Engineering, Wroclaw University o f Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw e-mail: adelajda.pala@pwr.edu.pl, jerzy.hola@pwr.edu.pl, lukasz.sadowski@pwr.edu.pl (corresponding author) Abstract: In the following article the use of the artificial neural network (ANN) for the non-destructive identi fication of the moisture content of saline ceramic bricks has been pr sented. ANN is taught and tested on a database f ormulated on the basis of experimental tests carried out with the use of non-destructive (NDT) dielectric, resis tive and microwave methods. The tests were performed on soli d clay bricks placed respectively in aqueous nitrat e, chloride and sulphate environments and also in an a quatic environment without salts as a comparison. A s a result of the carried out research and analysis it was pro ved that reliable non-destructive identification of the moisture content in saline ceramic bricks based on the param eters evaluated with the above-men...
Energies, 2021
The article deals with the problem of detecting moisture in the walls of historical buildings. As... more The article deals with the problem of detecting moisture in the walls of historical buildings. As part of the presented research, the following four methods based on mathematical modeling and machine learning were compared: total variation, least-angle regression, elastic net, and artificial neural networks. Based on the simulation data, the systems for the reconstruction of “pixel by pixel” tomographic images were trained. In order to test the reconstructive algorithms obtained during the research, images were generated based on real measurements and simulation cases. The method comparison was performed on the basis of three indicators: mean square error, relative image error, and image correlation coefficient. The above indicators were applied to four selected variants that corresponded to various parts of the walls. The variants differed in the dimensions of the tested wall sections, the number of electrodes used, and the resolution of the 3D image meshes. In all analyzed variant...
Materials, 2020
The article presents original complex methodology for the effective control of the entire process... more The article presents original complex methodology for the effective control of the entire process of executing floors made of cement-based materials. This methodology has been lacking in literature so far. The methodology was developed on the basis of many years of the authors’ experience, which was acquired when diagnosing the technical condition of such floors. The methodology was preceded by a synthetic summary of the most important technological and technical requirements for floors made of cement-based materials. It was also enriched with a discussion of the problem documented by sample research results showing the state that may be the result of disregarding and not performing the necessary control activities.
Automation in Construction, 2020
Taking into consideration the wide use of self-compacting concrete in engineering practice and th... more Taking into consideration the wide use of self-compacting concrete in engineering practice and the need to better understand its mechanical work, while at the same time attempting to use additives with a smaller grain size as a component of concrete, the paper presents the results of the authors' own research, conducted using the acoustic emission method, on the failure process of self-compacting compressed concrete both with and without the addition of 2.0% and 4.0% of SiO 2 and TiO 2 nanoparticles with regards to cement weight. The levels of crack initiation stresses σ i and critical stresses σ cr , which distinguish the individual stages of the investigated process, were determined. The obtained results were used to calculate the fatigue strength of all the concretes that were tested in the paper. Based on the achieved results, it can be concluded that the durability and safety of structures made of self-compacting concrete with the addition of SiO 2 and TiO 2 nanoparticles that are subjected to repeatedly variable loads will be higher when compared to structures made of concrete without these additives.
Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo, 2018
Trwałość zarówno warstwowych elementów betonowych, takich jak podłogi, jak i elementów betonowych... more Trwałość zarówno warstwowych elementów betonowych, takich jak podłogi, jak i elementów betonowych skorodowanych powierzchniowo i naprawionych poprzez nałożenie warstwy betonu naprawczego, istotnie zależy od należytego zespolenia warstw [1]. To należyte zespolenie zdefiniowane jest normowo [2] w rozumieniu żądanej minimalnej wartości przyczepności międzywarstwowej. Warto w tym miejscu powiedzieć, że zjawiska fizykochemiczne występujące na granicy dwóch stykających się materiałów, prowadzące do ich wzajemnego zespolenia, nazywane są przyczepnością-adhezją (łac. "adhaesio"-szczepienie). Wyróżnia się adhezję właściwą (specyficzną), związaną z oddziaływaniami chemicznymi i fizykochemicznymi, oraz adhezję mechaniczną, związaną z mechanicznym zakotwieniem materiału warstwy wierzchniej w porach i nierównościach materiału warstwy podkładowej [3-7]. Makroskopową miarą zespolenia betonu warstwy wierzchniej z betonem warstwy podkładowej (spodniej) jest wartość przyczepności przy odrywaniu f b , określana w praktyce niszczącą metodą odrywania na podstawie pomiaru wartości siły odrywającej za pomocą specjalnego siłownika [2]. Im wyższa jest wartość f b , tym zespolenie uznaje się za lepsze. Na podstawie tych badań można uzyskać "mapę przyczepności", na przykład na użytek zgrubnej lokalizacji rejonów wadliwych. Na podstawie tych badań można także ocenić, czy oderwanie nastąpiło na styku warstw (zniszczenie adhezyjne) czy w materiale warstwy wierzchniej lub podkładowej (zniszczenie kohezyjne), jednak bez uzyskania odpowiedzi na pytanie, dlaczego tak się stało. Oceny zespolenia warstw betonowych w skali makro można też dokonać przy wykorzystaniu do tego celu metody młoteczkowej, metody odpowiedzi na impuls A problem of a multi-scale approach of the assessment of interlayer bond between concrete layers
Structure and Environment, 2018
The paper presents the problems concerning the principles of developing expertise and performing ... more The paper presents the problems concerning the principles of developing expertise and performing tests on reinforced concrete structures. The situations that justify the need to provide expertise, the subject of which are constructions made of reinforced concrete, are described. A layout of the content of expertise that is usually adopted in practice has been included and commented on. The basic principles that should be followed when diagnosing the structures in question are provided. The available diagnostic methods and techniques, including non-destructive and semi non-destructive ones, are reviewed. This review is enriched with classifications that facilitate the selection of specific methods for individual diagnostic needs. In addition, useful literature with regards to the discussed topic has been indicated.