Search results for: LIGTHWEIGHT CONCRETE
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Latest Achievements in Concrete Structures Three-Dimensional Printing
PublicationWe can hear about three-dimensional printed concrete structures for several years, up to date solutions in this technology allow entire printing settlements of tiny concrete houses. Due to technical limitations, these houses are still small and not very durable, but undoubtedly, this technology is developing. Home printed in three-dimensional technology can be an alternative to modular container buildings implemented in areas affected...
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Properties of Old Concrete Built in the Former Leipziger Palace
PublicationThis research aims to determine the mechanical, chemical, and physical properties of old concrete used in the former Leipziger Palace in Wrocław, Poland. The cylindrical specimens were taken from the basement concrete walls using a concrete core borehole diamond drill machine. The determination of the durability and strength of old concrete was based on specified chosen properties of the old concrete obtained through the following...
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CONCRETE MIX DESIGN USING ABRAMS AND BOLOMEY METHODS
PublicationOne way to reduce the consumption of cement is to optimize its use. Many known methods of concrete design, based on the Abrams law and the Bolomey method. Therefore, the authors chose those methods for analysis. The concrete composition with the assumed strength class, calculated by any method differs significantly. This applies especially to the cement content, as its content in the composition of concrete varies from 20 to 50%....
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Chemical and Mechanical Properties of 70-Year-Old Concrete
PublicationThe aim of this research is to determine the durability and strength of concrete continuous footing based on the chosen mechanical, physical, and chemical properties of the concrete. The presented investigations constitute some opinions from experts on the bearing capacity of concrete continuous footing and the possibilities of carrying additional loads and extended working life. The cylindrical specimens were taken from continuous...
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Comparison of calculated and measured thermal stresses in asphalt concrete
PublicationThe paper presents the comparison of calculated and measured thermal stresses induced in restrained asphalt concrete specimens by cooling. Thermal stresses were measured in the Thermal Stress Restrained Specimen Test. The calculations of thermal stresses were performed with the use of a theoretical formula based on the temperature dependent stiffness modulus. The novel approach applied in this paper was that the stiffness modulus...
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Numerical FDM modelling of wave propagation in concrete structure
PublicationThe article presents application of finite difference method to damage detection and its size evaluation in concrete structure by elastic wave propagation method. The simulations of wave propagation in concrete structure were performed for six different damage scenarios. Damages were modelled as areas with changed material properties. Investigation focused on the influence of damage size on the energy of wave reflection. Presented...
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Application of gpr method in diagnostics of reinforced concrete structures
PublicationThis paper presents an application of the ground penetration method (GPR) for diagnostics of reinforced concrete structures. In situ measurements were conducted for three civil engineering structures: the ground floor structure, the abutment of the railway viaduct and the concrete well. The dual polarized ground penetrating radar with the antenna operating at a center frequency of 2 GHz was used for GPR surveys. Three different...
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Modelling of concrete behaviour in uniaxial compression and tension with DEM.
PublicationW artykule omowiono wyniki modelowania betonu podczas jednoosiowego sciskania i rozciagania stosujac metode elementów dyskretnych. Beton zostal opisany jako material 3-fazowy (kruszywo, zaprawa cementowa i strefy kontaktu). Szczegolna uwage zwrocono na zjawiska mikro-strukturalne na poziomie kruszywa (lancuchy sil, wiry, obroty ziaren). Wyniki numeryczne zostaly porownano z wynikami badan doswiadczalnych.
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Steel-fibrous concrete -experiments and a numerical discrete model
PublicationW książce przedstawiono wyniki doświadczalne i numeryczne dotyczące rys w elementach betonowych wzmocnionych włóknami stalowymi dla różnych problemów brzegowych quasi-statycznych. Obliczenia wykonano przy zastosowaniu własnego oryginalnego modelu sieciowego. W modelu beton z włóknami stalowymi był modelowany na poziomie mezo. W obliczeniach uwzględniono strefy kontaktu miedzy kruszywem a zaczynem oraz włóknami a zaczynem.
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3D DEM simulations of fracture in reinforced concrete beams
PublicationArtykuł dotyczy zachowania się belki żelbetowej bez zbrojenia pionowego przy trzypunktowym zginaniu. Belka uległa zniszczeniu wskutek ścinania z powodu obecności nadmiernego zbrojenia podłużnego. Eksperymenty przeprowadzono w skali laboratoryjnej z wykorzystaniem systemu mikro-CT, a następnie odtworzono je w analizach numerycznych stosując metodą elementów dyskretnych 3D (DEM). Zastosowano 4-fazowy model betonu z mezostrukturą,...
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Modelling of concrete using lattice and discrete element method
PublicationModelowanie betonu przy zastosowaniu metody siatkowej i metody elementów dyskretnych.
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Dynamic analysis of the impact of the wind spectrum according to the theory of Davenport for lightweight structures of the roof in sports hall Czyzyna in Cracow.
PublicationThe main aim of this analysis is to characterize numerical simulations connected with modeling dynamic influence of wind on the lightweight structures of the roof in sports hall – “Czyżyna”. This hall is built in Cracow. The article also involves the proposals of the solutions connected with dynamic influence of the wind – Davenport’s method has been used. These proposals have not been taken into consideration at the detailed engineering...
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A constitutive model for concrete based on continuum theory with non-local softening coupled with eXtended Finite Element Method. Computational Modelling of Concrete Structures,
PublicationArtykuł omawia model połączony ciągły-nieciągły do modelowania stref lokalizacji i rys w betonie niezbrojonym. Obliczenia wykonano stosując rozszerzoną metodę elementów skończonych. Wyniki numeryczne porównano z doświadczeniami.
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Modes of Failure Analysis in Reinforced Concrete Beam Using Laser Scanning and Synchro-Photogrammetry - How to apply optical technologies in the diagnosis of reinforced concrete elements?
PublicationThe following paper reveal the limitations and possibilities of terrestrial laser scanning technology adaptation in diagnostics of reinforced concrete beams. In this paper, authors present potential spectrum of TLS use in modes of failure analysis of R-C beams and determines under which conditions the laser technologies might be applied. Research was carried out at the Regional Laboratory of Structural Engineering at Gdansk University...
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Influence of lightweight structures used in swimming pools and water parks objects on their functionality, building form and spatial-visual effects indoors.
PublicationSpeaking about architecture of swimming facilities and water parks we have in mind their form, function , design and detail, texture and color. A particularly important element of the architecture of these buildings was and still is the structure.
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An efficient and robust method for predicting asphalt concrete dynamic modulus
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Machine learning-based prediction of preplaced aggregate concrete characteristics
PublicationPreplaced-Aggregate Concrete (PAC) is a type of preplaced concrete where coarse aggregate is placed in the mold and a Portland cement-sand grout with admixtures is injected to fill the voids. Due to the complex nature of PAC, many studies were conducted to determine the effects of admixtures and the compressive and tensile strengths of PAC. Considering that a prediction tool is needed to estimate the compressive and tensile...
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Concrete corrosion against penetration of mineral oil application of impregnants
PublicationOleje stanowią związki organiczne, w skład których wchodzą kwasy tłuszczowe nasycone i nienasycone oraz gliceryny różnego rodzaju. W zależności od rodzaju i właściwości olejów agresywność ich w stosunku do betonu jest różna. Olej izoluje dostęp wody do składników betonu, dlatego nie następuje dalsza hydratacja i przyrost wytrzymałości. Przesycenie betonu olejami powoduje wskutek obniżenia tarcia wewnętrznego tworzywa obniżenie...
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Verification of the criteria for evaluation of water and frost resistance of asphalt concrete
PublicationThe paper presents the results of field investigation - condition survey of existing pavements and the results of laboratory tests on water and frost resistance of samples cored from the these pavements. The purpose of testing was to verify the criteria for evaluation of the resistance of asphalt concrete to the action of water and frost by way of comparing the results of field and laboratory tests, followed by evaluation of their...
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Computational modelling of concrete behaviour under static and dynamic conditions
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Application of guided waves in the evaluation of steel-concrete adhesive connection
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Properties of Composite Modified with Limestone Powder for 3D Concrete Printing
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SIGNIFICANT GUIDELINE FOR THE DAMAGE INDICES APPLIED TO REINFORCED CONCRETE STRUCTURES
PublicationIn this paper, based on a deep overview and literature study, the different formulas proposed for damage indices (DIs) applied to reinforced concrete structures under monotonic or cyclic loading are classified and presented. The DIs are applied to quantify the damages to structures, ranging from zero to one. Normally, they are applied to make a decision for repairing or demolition of the structures in the post-earthquake phases. Keywords:...
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Estimation of the parameters of the discrete model of a steel–concrete composite beam
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Experimental and numerical investigations for GPR evaluation of reinforced concrete footbridge
PublicationThe GPR method has increasingly found application in non-destructive testing of reinforced concrete structures. This paper presents the new approach of modelling of the electromagnetic wave propagation for reinforced concrete structures with a complex system of the reinforcement. Simulations of the GPR field were performed on a three-dimensional model of a footbridge using the FDTD method. Numerical maps were compared with results...
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Concrete versus green corridors in road planning. Gdansk case
PublicationThe aim of an article is to present the threats which may be caused by the construction of the transit road inside the city structure, and some mitigation measures aiming to eliminate or minimize environmental and landscape damages and social problems. Theoretical guidelines and conclusions will be followed by the example illustrating the problem. As an answer, some guidelines enabling sustainable road planning will be presented....
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Monitoring of concrete curing in extradosed bridge supported by numerical simulation
PublicationThe paper describes a mathematical model of concrete curing taking into account kinetics of setting reactions. The numerical model is implemented in the author’s program that was used to monitor thermal effects recorded in the concrete bottom plate of the extradosed bridge. Numerical approach was verified by experimental measurements and used for assessment of the current compressive strength due to degree of hydration of fresh...
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Corrosion behavior of concrete produced with diatomite and zeolite exposed to chlorides
PublicationChloride induced reinforcement corrosion is widely accepted to be the most frequent mechanism causing premature degradation of reinforced concrete structures. The electrochemical impedance of reinforcing steel in diatomite- and zeolite-containing concrete exposed to sodium chloride was assessed. Chemical, physical and mineralogical properties of three concrete samples (20% diatomite, 20% zeolite, and a reference containing neither)...
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Static load test on concrete pile – instrumentation and results interpretation
PublicationFor some time (since 8-10 years in Poland) a special static load tests on instrumented piles are carried out. Such studies are usually of a scientific nature and provide detailed quantitative data on the load transfer into the ground and characteristics of particular soil layers interaction with a pile shaft and pile base. Deep knowledge about the pile-subsoil interaction can be applied for a various design purposes, e.g. numerical...
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Application of guided waves in the evaluation of steel-concrete adhesive connection
PublicationThe aim of the paper is the application of guided waves in the evaluation of a condition state of adhesive connection between steel and concrete. The study concerns a push-out specimen consisting of two steel plates glued to opposite faces of a concrete cube with the use of structural adhesive. Wave propagation in the specimen without external load is investigated both experimentally and numerically. The second stage of the investigation...
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Durability of Asphalt Concrete Subjected to Deteriorating Effects of Water and Frost
PublicationThe paper presents testing of the detrimental effects of water and frost on asphalt pavements. It included laboratory testing of 5 fatigue life of asphalt concrete that was subjected to action of water and frost and field testing of damages caused by water and frost on 6 existing asphalt pavements, such as stripping, raveling, and potholes. Laboratory simulation of water and frost action was based on the 7 original AASHTO T283...
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Simulations of fracture in concrete elements using continuous and discontinuous models
PublicationArtykuł przedstawia wyniki symulacji MES w elementach betonowych przy zastosowaniu modeli ciągłych i nieciągłych. Stosując modele ciągłe symulowano proces lokalizacji odkształceń. Stosując modele nieciągłe symulowano proces zarysowania. Obliczenia wykonano dla różnych typów obciążeń.
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Environmentally friendly material solutions in the technology of autoclaved aerated concrete
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Effect of perlite waste addition on the properties of autoclaved aerated concrete
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Influence of grout proportions on modulus of elascity of two-stage concrete
PublicationOmówiono badania doświadczalne przeprowadzone dla betonu dwuetapowego. Beton wykonano z kruszywa otoczakowego przy zastosowaniu trzech różnych proporcji w/c i c/p. Na drodze statystycznej opracowano prosty wzór umożliwiający wstępne szacowanie wartości siecznego modułu Younga. Ponieważ metoda dwuetapowa pozwala na zachowanie kontaktu pomiędzy poszczególnymi elementami kamiennego szkieletu wypełniającego formę, wytrzymałość uzyskanego...
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Stress strain relations and modulus of elascity of two stage concrete.
PublicationOmówiono badania doświadczalne przeprowadzone dla betonu dwuetapowego. Beton wykonano z trzech różnych kruszyw przy zastosowaniu trzech różnych proporcji w/c i c/p. Wyznaczono związki pomiędzy naprężeniami i odkształceniami. Na drodze statystycznej opracowano wzory umożliwiające wstępne szacowanie wartości siecznego modułu Younga. Ponieważ metoda dwuetapowa pozwala na zachowanie kontaktu pomiędzy poszczególnymi elementami kamiennego...
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Fibres from recycled post-consumer tyres for concrete reinforcement
PublicationW pracy przedstawiono aktualną sytuację dot. wykorzystania drutu stalowego z recyklingu opon samochodowych. Przedstawiono wyniki badań przeprowadzonych w laboratorium Katedry Konstrukcji Betonowych i Technologii Betonu nad zastosowaniem włókien stalowych z recyklingu do zbrojenia betonu. Otrzymane wyniki porównano z próbkami fibrobetonu uzyskanego na bazie przemysłowo produkowanych włókien stalowych.
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Damage of a post-tensioned concrete bridge – Unwanted cracks of the girders
PublicationThe cracking of a post-tensioned T-beam superstructure, which was built using the incremental launching method, is analyzed in the paper. The problem is studied in detail, as specific damage was observed in the form of longitudinal cracks, especially in the mid-height zone of the girder at the interface of two assembly sections. The paper is a case study. A detailed inspection is done and non-destructive testing results of the...
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...
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DESIGN ERRORS CAUSE AN EMERGENCY OF THE REINFORCED CONCRETE TANK FOR COKE
PublicationThe quality of the developed design documentation and the maintenance of the technological regime during construction works have a decisive impact on the subsequent safety of the structure, as well as the safety of use of the building. The paper describes the defects and damages of an open, rectangular reinforced concrete tank for hot process water, which failed during a short period of operation. The article also presents the...
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Mechanical properties of two-stage concrete modified by silica fume
PublicationAbstract. Two-stage concretes, despite the fact that they have proven themselves in various types of construction, have not been studied to the same extent as traditional heavy concretes. Therefore, the article developed the composition of frame concrete with various additives in the composition of the cement-sand mortar. A comparison of the mechanical characteristics of the developed compositions with the addition of silica fume...
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Experimental study on ultrasonic monitoring of splitting failure in reinforced concrete
PublicationThis paper investigates inspection of reinforced concrete elements sensitive to the splitting failure. The behaviour of a reinforced concrete specimen subjected to a tensile stress is considered. The damage detection procedure is based on the ultrasonic wave propagation technique. The piezoelectric transducers are located on both ends of the specimen and the measurements are taken periodically during the incrementally increased...
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Analysis of Transparent Concrete as an Innovative Material Used in Civil Engineering
PublicationSince the dawn of history concrete has been, right behind stone and brick, one of the oldest building materials. The ancient Romans took advantage of its opportunities. They constructed amazing architectural objects, which survived centuries as whole buildings or parts of them. Concrete is so ubiquitous, that when we are walking in a newer districts of cities we are virtually surrounded by concrete from everywhere. Sometimes...
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The Application of Fibres from Recycled Postconsumer Tyres for Concrete Reinforcement
PublicationPoland as a Member State is obliged to implement the EU specific environmental legislation focused on the reduction, transport and treatment of waste. The Landfill Directive prohibited the landfilling of whole tyres and their by-products. Although the EU Directive of Waste limits the use of tyres as secondary fuel, Poland is still the EU leader in burning tyres in cement kilns. Post-consumer tyres are utilised in a number of...
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Ultrasonic diagnostics of concrete T-beams used in bridge structures
PublicationThis paper describes a method of ultrasonic diagnostics used for prefabricated concrete elements. The studies are focused on the applicability of nondestructive techniques based on impulse and wave packet induced elastic waves for the condition assessment of T-shaped bridge beams. Experimental tests were performed for the prestressed beam used for the superstructure of the viaduct on A1 highway near Toruń. In addition numerical...
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Causes of damage and methods of repairing floor made on polystyrene concrete
PublicationThe paper describes damages, tests and repair of the floor made on existing ceiling and expanded polystyrene concrete underlay. The floor was built on a reinforced concrete ceiling with an area of about 1050 m2. Significant damage in the form of cracks, detachments and unevenness was found in the floor. In order to determine the causes of damage, in situ tests and laboratory tests were carried out. It was found that the damage...
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Concrete-filled FRP tubular members in marine and bridge structures
PublicationConcrete core of the concrete-filled tubes (CFTs) with circular cross-section is in the case of an axial compression subjected to a spatial state of compressive stresses. This state leads to enhancement in the concrete strength. The enhancement is utilized in Eurocode 4 design procedures for CFSTs (i.e. CFTs with tube made of steel). The structural design of CFFTs (i.e. CFTs with tube made of Fibre Reinforced Polymer - FRP) is...
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Maturity curve for estimating the in-place strength of high performance concrete
PublicationThe paper presents the maturity curve for estimating the in-place early-age compressive strength of concrete. The development of appropriate maturity curve is a complex process. It is important to correctly determine the datum temperature and activation energy, which can be obtained in mortar tests. This paper describes an investigation of the accuracy of the maturity method to estimate the strength when different way to rate constant...
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Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation
PublicationThe article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous...
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Machine learning-based prediction of preplaced aggregate concrete characteristics
PublicationPreplaced-Aggregate Concrete (PAC) is a type of preplaced concrete where coarse aggregate is placed in the mold and a Portland cement-sand grout with admixtures is injected to fill the voids. Due to the complex nature of PAC, many studies were conducted to determine the effects of admixtures and the compressive and tensile strengths of PAC. Considering that a prediction tool is needed to estimate the compressive and tensile strengths...