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Wyniki wyszukiwania dla: geopolymer concrete
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Computers and Concrete
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Concrete Operators
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CEMENT & CONCRETE COMPOSITES
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CEMENT CONCRETE AND AGGREGATES
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Advances in Concrete Construction
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Nordic Concrete Research
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Hydraulic conductivity of a biopolymer treated sand
PublikacjaThis paper presents results of laboratory assessment of creating seepage barriers in a sandy soil using biopolymer additives (bio substance), which consist of polysaccharides and water. Polysaccharides strongly interact with water to produce a viscous suspension. The aim of the conducted work was to investigate the influence of a biosubstance employed in a highly permeable sandy soil. The amount of the biopolymer used in a sample...
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Investigation on Mode I Fracture Behavior of Hybrid Fiber-Reinforced Geopolymer Composites
PublikacjaRecent reports in the literature have shown that fber-reinforced geopolymer composites (FRGC) made with monofbers exhibit a signifcant enhancement in fracture energy. However, many aspects of the fracture performance of hybrid fberreinforced geopolymer composites (HFRGC) remain largely unexploited, and these are predominant for the structures. For the frst time, the mode I fracture energy of HFRGC is investigated. The mode I behavior...
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Effect of surface modification on starch biopolymer wettability
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Laboratory assessment of permeability of sand and biopolymer mixtures
PublikacjaLaboratory assessment of permeability of sand and biopolymer mixtures. This research presents a method of creating seepage barriers in a sandy soil using biopolymer additives (biosubstance), which consist of polysaccharides and water. Polysaccharides strongly interact with water to produce a viscous suspension. The paper aims to investigate the infl uence of a biosubstance employed in a highly permeable sandy soil. Amount of the...
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Biopolymer based nanomaterials in drug delivery systems: A review
PublikacjaDrug delivery systems (DDS) are used to achieve a higher therapeutic effects of a pharmaceutical drug or natural compound in a specific diseased site with minimal toxicological effect and these systems consists of liposomes, microspheres, gels, prodrugs and many. Nanotechnology is a rapidly developing multi-disciplinary science that ensures the fabrication of the polymers to nanometer scale for various medical applications. Uses...
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Some geomechanical properties of a biopolymer treated medium sand
PublikacjaSome geomechanical properties of a biopolymer treated medium sand. This paper presents a laboratory assessment of geomechanical properties of sandy soil improved by biopolymer application. Additives (biosubstance) consist of polysaccharides and water. Biosubstance used in the project was xanthan gum, which comes from bacteria Xanthomonas campestris. Triaxial shear compression tests and unconfi ned compression tests were carried...
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Journal of Advanced Concrete Technology
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Journal of the Korea Concrete Institute
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Structural Concrete
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Evaluation of Glass Powder-Based Geopolymer Stabilized Road Bases Containing Recycled Waste Glass Aggregate
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Poloxamer: A versatile tri-block copolymer for biomedical applications
PublikacjaPoloxamers, also called Pluronic, belong to a unique class of synthetic tri-block copolymers containing central hydrophobic chains of poly(propylene oxide) sandwiched between two hydrophilic chains of poly(ethylene oxide). Some chemical characteristics of poloxamers such as temperature-dependent self-assembly and thermo-reversible behavior along with biocompatibility and physiochemical properties make poloxamer-based biomaterials...
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Influence of stirrups in a concrete shell on strengthening reinforced concrete column
PublikacjaTwelve concrete columns, with a 150x150mm square section and three columns with a circular section (d=200mm), are tested to investigate the effect of strengthening by RC jacket. Based on a confined concrete model for axial static loading, an analytical methods, reported in the literature are proposed to predict the behavior of columns with RC jacket. The results support the conception that the effect of strengthening depends...
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Biopolymer-based composites for tissue engineering applications: A basis for future opportunities
PublikacjaBiomimetic scaffolds supporting tissue regeneration are complex materials with multifunctional characteristics. The unique biocompatibility and biodegradability of biopolymers make them excellent candidates for tissue engineering and regenerative medicine. Biopolymers, which have a wide range of properties, can be obtained from different natural sources. Depending on the target tissue, biopolymers can be engineered to meet a series...
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A comparative study on geopolymers synthesized by different classes of fly ash after exposure to elevated temperatures
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New Contree
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Evaluation of Mechanical Properties of Two-Stage Concrete and Conventional Concrete Using Nondestructive Tests
PublikacjaDifferent types of concrete mixtures are used as building materials. The manufacturing process of two-stage concrete (TSC) differs from that of conventional concrete. This study investigated conventional mechanical properties derive empirical relations for estimation of the mechanical parameters of TSC and conventional concrete mixtures. TSC was used to prepare 216 specimens and conventional concrete was used to prepare 108 specimens...
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Investigation into the Effect of Spinel Pigments on the Photostability and Combustion Properties of Ethylene-Norbornene Copolymer
PublikacjaMulticolor ethylene-norbornene (EN) composites filled with three different spinel pigments (Cobalt Green-PG50, Zinc Iron Yellow-PY 119, Praseodym Yellow-PY159) were prepared by melt mixing and characterized in terms of their stability under destructive environmental conditions. The EN films were subjected to accelerated aging by ultraviolet (UV) photooxidation for 300 h, 600 h, or 900 h. The mechanical performance of the EN composites...
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Rapid communication: Computational simulation and analysis of a candidate for the design of a novel silk-based biopolymer
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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete
PublikacjaPreplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...
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Mechanical properties of concrete mixes M0-M100 concrete mixes
Dane BadawczeDataset of hardneded properties of concretes containing different amount of magnetite aggregate (M0-M100) mixes.Excel file consists results of:
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Fresh properties of concrete mixes M0-M100 concrete mixes
Dane BadawczeDataset of fresh properties of concretes containing different amount of magnetite aggregate (M0-M100) mixes.*. ODS - open-source spreadsheet file file consists results of:
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Effects of Xanthan Gum Biopolymer on the Permeability, Odometer, Unconfined Compressive and Triaxial Shear Behavior of a Sand
PublikacjaBiopolymers, which are microbially induced polymers, can be used as an alternative material to improve engineering performance of soils. In this paper, a laboratory study of 0.075-1.0 mm size sand and biopolymer (i.e., xanthan gum) mixtures with various mix ratios (0%, 0.5%, 1.0%, and 1.5%) was performed. The materials, specimen preparation, and test methods are described, as are the results of a suite of permeability, odometer, unconfined...
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Standard and modified falling mass impact tests on preplaced aggregatefibrous concrete and slurry infiltrated fibrous concrete
PublikacjaAlthough several studies have been conducted to evaluate the impact response of concrete using theAmerican Concrete Institute (ACI) 544-2R falling mass impact test, the variations in test results are themain drawback of this testing method. This study aims to reduce the variations in experimental impacttest results by introducing two simple test setup modifications; (1) using coarse or fine aggregate bed-ding as an alternative...
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Evaluation of the resistance of steel–concrete adhesive connection in reinforced concrete beams using guided wave propagation
PublikacjaThe development of the nondestructive diagnostic methods is of significant importance in the last decades. A special attention is paid to diagnostics of reinforced concrete structures, which are very popular in the civil engineering field. A possible use of the guided waves in the estimation of the resistance of steel–concrete adhesive connection is studied in the following paper. The relationships relating adhesive connection...
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Concrete elements cast in febric forms
PublikacjaPrzedstawiono wyniki badań wytrzymałościowych elementów betonowych wylewanych w wiotkich formach wykonanych z materiałów syntetycznych. Badania przeprowadzono dla modelu ściany/słupa. Zbadano mechaniczne i chemiczne własności 10 różnych materiałów syntetycznych. Wybrano materiał o przepuszczalności umożliwiającej wykonanie monolitycznej konstrukcji. Z 12 zbadanych mieszanek betonowych do dalszej analizy wyselekcjonowano trzy. Badania...
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Numerical simulation of hardening of concrete plate
PublikacjaThe paper presents a theoretical formulation of concrete curing in order to predict temperature evolution and strength development. The model of heat flow is based on a well-known Fourier equation. The numerical solution is implemented by means of the Finite Difference Method. In order to verify the model, the in situ temperature measurements at the top plate of a road bridge were carried out. A high agreement between numerical...
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Simulation of fracture process in fibrous concrete
PublikacjaArtykuł omawia wyniki modelowania procesu zarysowania w elementach betonowych zawierające stalowe włókna przy zastosowaniu dyskretnego modelu kratownicowego. Beton był modelowany na poziomie mezoskali z uwzględnieniem 5 faz: kruszywa, zaczynu cementowego, włókien i obu stref kontaktu. Obliczenia wykonano dla jednoosiowego ściskania oraz jednoosiowego rozciągania.
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Mesoscopic modelling of strain localization in concrete
PublikacjaArtykuł omawia obliczenie lokalizacji odkształceń w elementach betonowych poddanych zginaniu. Obliczenia wykonano dla betonu na poziomie mezo przy zastosowaniu modelu zniszczeniowego z degradacją sztywności rozszerzonego o nielokalność. Zbadano wpływ zagęszczenia kruszywa, wielkość kruszywa, kształtu kruszywa oraz długości charakterystycznej na szerokość lokalizacji.
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Comparison of low-temperature cracks intensity on pavements with high modulus asphalt concrete and conventional asphalt concrete bases
PublikacjaHigh modulus asphalt concrete (HMAC) base courses provide very good resistance to rutting and fatigue but they can increase the risk of low-temperature cracking as compared with conventional asphalt concrete (AC). The article presents the comparison of these two road materials in terms of low-temperature cracking. The statistical method based on the ordered logistic regression model was used. The analysis was based on results of...
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Tailoring Diffusional Fields in Zwitterion/Dopamine Copolymer Electropolymerized at Carbon Nanowalls for Sensitive Recognition of Neurotransmitters
PublikacjaThe importance of neurotransmitter sensing in the diagnosis and treatment of many psychological illnesses and neurodegenerative diseases is non-negotiable. For electrochemical sensors to become widespread and accurate, a long journey must be undertaken for each device, from understanding the materials at the molecular level to real applications in biological fluids. We report a modification of diamondized boron-doped carbon nanowalls...
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Effective assessment of biopolymer-based multifunctional sorbents for the remediation of environmentally hazardous contaminants from aqueous solutions
PublikacjaPersistent contaminants in wastewater effluent pose a significant threat to aquatic life and are one of the most significant environmental concerns of our time. Although there are a variety of traditional methods available in wastewater treatment, including adsorption, coagulation, flocculation, ion exchange, membrane filtration, co-precipitation and solvent extraction, none of these have been found to be significantly cost-effective...
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Biopolymers in designing modern antimicrobial medical materials. Part I. Biopolymer medical materials - collagen, chitosan
PublikacjaThe article is a review of the literature concerning the possible use of biopolymers for the preparation of dressings with antimicrobial activity. Authors show the potential of biopolymers: collagen and chitosan - which have the ability to immobilize and control the release of various active compounds - for providing the appropriate antibacterial, bacteriostatic and wound healing properties. Types of threats, for which the dressing...
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CONCRETE MIX DESIGN USING SIMPLE EQUATIONS
PublikacjaThe behaviour of concrete, whether fresh or har dened, depends basically on the beha viour of its components and the r elationship between them, ther efore, obtaining a concr ete with cer tain pr operties depends fundamentally on the concr ete mix design. Concr ete mix design gener ally includes two main steps: 1-Selection of the main components suitable for the concr...
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Machine Learning Techniques in Concrete Mix Design
PublikacjaConcrete mix design is a complex and multistage process in which we try to find the best composition of ingredients to create good performing concrete. In contemporary literature, as well as in state-of-the-art corporate practice, there are some methods of concrete mix design, from which the most popular are methods derived from The Three Equation Method. One of the most important features of concrete is compressive strength, which...
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Uniform corrosion monitoring of carbon steel in concrete
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Impregnation vibro-pressed concrete pavement bricks.
PublikacjaW materiałach przedstawiono wyniki badań uzyskanych podczas prób impregnacji wibroprasowanych elementów betonowych. Celem badań było określenie odpowiedniego składu kompozycji impregnacyjnej, aby uzyskać najlepszy efekt zabezpieczenia powierzchni betonu przed wnikaniem cieczy organicznych np. oleju mineralnego.
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Concrete-domain reasoning techniques in knowledge cartography
PublikacjaWiele zjawisk w świecie rzeczywistym opisujemy korzystając z liczb i symboli. W ramach naszej pracy jako punkt wyjścia traktujemy podejście kartograficzne opracowane na potrzeby wnioskowania z ontologii opartych na logice opisowej i pozwalające na efektywne przetwarzanie baz wiedzy zwierających dużą liczbę osobników. Niniejszy artykuł przedstawia rozszerzenie podejścia kartograficznego pozwalające na wnioskowanie z wartości symbolicznych,...
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Damage Detection of Steel-Concrete Composite Beam
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Minimal transverse reinforcement of reinforced concrete members
PublikacjaW pierwszej części pracy omówiono zagadnienia dotyczące minimalnego zbrojenia na ścinanie elementów żelbetowych w kontekście norm europejskich oraz pozaeuropejskich. W drugiej części pracy dokonano analizy wyników badań eksperymentalnych dotyczących nośności elementów bez zbrojenia poprzecznego, które stanowią podstawę do weryfikacji zaleceń normowych w zakresie minimalnego zbrojenia na ścinanie.
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Uniform corrosion monitoring of carbon steel in concrete.
PublikacjaW przypadku korozji prętów zbrojeniowych w żelbecie zaobserwowane zostały obszary wzmożonego zaatakowania. Pomiar prądowego i napięciowego szumu elektrochemicznego umożliwia wyznaczenie szybkości korozji ogólnej a zmiany parametrów statystycznych przebiegów szumowych umożliwiają detekcję występowania przestrzennych rejonów intensyfikacji korozji. Przedstawione rezultaty, oparte na wykorzystaniu odpowiedniego układu zastępczego,...
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The lethal effect of hydrotechnical concrete on freshwater Bivalvia
PublikacjaMost hydrotechnical buildings under construction demand the concrete mixture to be set directly under water. The main reason for such a procedure is to limit the washing away of the the concrete binding mixture and to increase the efficiency of organisation of work so as to ensure continuity in concreting. The impact on the aquatic environment of recent developments in concrete technology and the use of new components has not yet...
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Concrete mix design using machine learning
PublikacjaDesigning a concrete mix is a process of synthesizing many components, it is not a simple process and requires extensive technical knowledge. The design process itself focuses on obtaining the required strength of concrete. Very often designing a concrete mix takes into account the need to maintain the proper water-demand and frost-resistance features. The parameters that influence the concrete class most significantly are the...
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Experimental tests of reinforced concrete deep-beams
PublikacjaThe paper presents results of experimental research of the reinforced concrete deep beam with a spatial arrangement. Tested structural elements consist of the cantilever deep beam loaded on the height and transverse deep beam with hanging on it another one. The analysis includes crack morphology, effort of steel and load distribution. The article verified effectiveness of two different kind of reinforcement in both tested deep...
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Ultrasound monitoring for evaluation of damage in reinforced concrete
PublikacjaThe paper deals with automated monitoring of damage evolution in concrete elements subjected to three-point bending tests. The monitoring is based on the nonlinear interactions of traveling ultrasonic waves with micro-crack zones inside the concrete specimens and surface-breaking cracks. The developed procedure assumes semi-continuous ultrasonic testing during the element full loading cycle and generation of the power spectral...
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GPR simulations for diagnostics of a reinforced concrete beam
PublikacjaThe most popular technique for modelling of an electromagnetic field, the finite difference time domain (FDTD) method, has recently become a popular technique as an interpretation tool for ground penetrating radar (GPR) measurements. The aim of this study is to detect the size and the position of damage in a reinforced concrete beam using GPR maps. Numerical simulations were carried out using the finite differ-ence time domain...
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A two-scale (FEM-DEM) approach for concrete
PublikacjaArtykuł omawia dwu-skalowe podejście do betonu przy wykorzystaniu modelu Mes i DEM. Metodę elementów skończonych zastosowano na poziomie makro. Na poziomie mikro zastosowano metodę elementów dyskretnych. Macierz sztywności wyznaczono na podstawie tensora naprężeń wyznaczonego w skali mikro. Wyniki numeryczne dwusalowe porównano z wynikami dyskretnymi dla całego obszaru.
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A coupled continuous-discontinuous approach to concrete elements.
PublikacjaArtykuł omawia zastosowanie metody elementów skończonych do opisu procesu pękania elementów betonowych z równoczesnym uwzględnieniem lokalizacji odkształceń i rys. Obliczenia wykonano dla elementów poddanych zginaniu. Wyniki porównano z doświadczeniami.
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Modelling of behavior of plain concrete using DEM
PublikacjaW artykule pokazano rozwój różnych zjawisk mikrostrukturalnych na poziomie kruszywa w betonie podczas jednoosiowego ściskania i rozciągania.. Obliczenia wykonano stosując metodę DEM. Wyniki na poziomie globalnym porównano doświadczalnymi. Szczególna uwagę zwrócono na propagację rys i szerokość lokalizacji odkształceń.
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Modelling the effect of composition on the tensile properties of concrete
PublikacjaRozdział omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu. Zaproponowano 2 metody określenia reprezentatywnego elementu objętościowego w betonie.
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Continuous and discontinuous modeling of cracks in concrete elements
PublikacjaW artykule przedstawiono różne sposoby modelowania rys w elementach betonowych w warunkach mieszanego sposobu obciążenia przy zastosowaniu modeli ciągłych i nieciągłych. Symulacje wykonano przy zastosowaniu 3 różnych modeli ciągłych: modelu sprężysto-plastycznego, modelu w ramach mechaniki zniszczeniowej i modelu rys rozmytych z rysami obracającymi się oraz 1 modelu nieciągłego przy zastosowaniu stref kontaktu..
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Size effect in concrete under splitting tension
PublikacjaThe size effect is a fundamental phenomenon in concrete materials. It denotes that both the nominal structural strength and material ductility always decrease with increasing element size under tension. In the paper splitting tensile tests on cylindrical concrete specimens with the different diameter were carried out. Two types of the loading strip (plywood board and steel cylinder) were used. The concrete strength and ductility...
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SAXS examination of the water evaporation process from silica materials coated with a polysaccharide–polyimine copolymer layer
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Effects of Surface Pretreatment of Titanium Substrates on Properties of Electrophoretically Deposited Biopolymer Chitosan/Eudragit E 100 Coatings
PublikacjaThe preparation of the metal surface before coating application is fundamental in determining the properties of the coatings, particularly the roughness, adhesion, and corrosion resistance. In this work, chitosan/Eudragit E 100 (chit/EE100) were fabricated by electrophoretic deposition (EPD) and both their microstructure and properties were investigated. The present research is aimed at characterizing the effects of the surface...
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Thermal degradation behavior of lignin-modified porous styrene-divinylbenzene and styrene-bisphenol A glycerolate diacrylate copolymer microspheres
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Properties of Old Concrete Built in the Former Leipziger Palace
PublikacjaThis 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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Latest Achievements in Concrete Structures Three-Dimensional Printing
PublikacjaWe 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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Influence of selected additives and admixtures on underwater concrete and the environment
PublikacjaThe intensive civilization development has an influence on searching for new possibilities connected with extension of city agglomerations, both the areas of flat building and the industrial areas. One of the most interesting solution is to use water reservoirs, rivers and sea areas. The extension of buildings has an influence on building materials, especially hydrotechnical, which means development of production of hydrotechnical...
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Chemical and Mechanical Properties of 70-Year-Old Concrete
PublikacjaThe 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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Parameter estimation of a discrete model of a reinforced concrete slab
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Self-compacting grout to produce two-stage concrete
PublikacjaTraditional concrete (TC) is primarily composed...
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Partially prestressed concrete beams with bonded and unbonded strands
PublikacjaThis article relate the tests of partially prestressed concrete beams. There is presented the research programme - geometry of elements, method of loading, the materials and variables. There have been shown preliminary test results of prestressed concrete elements with bonded and unbonded strands, and compared to the test results of R.C. beam.
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Experimental investigations of concrete dowels in composite floor system
PublikacjaOpisano nowy system stropow zespolonych umozliwiajacych montaz instalacji klimatyzacyjnych, wentylacyjnych i grzewczych w przestrzeni pomiedzy dwoma plytami betonowymi konstrukcji stropu: gorna i dolna. Obie plyty polaczone sa wzajemnie srodnikami stalowymi z wycieciami u gory i na dole w ksztalcie 'puzzle', ktore we wspolpracy z plyta betonowa tworza tzw. dyble betonowe. Wykonano badania laboratoryjne typu 'Push-out' tych polaczen...
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The influence of polypropylene fibres on the properties of fresh and hardened concrete
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Effectiveness of Concrete Reinforcement with Recycled Tyre Steel Fibres
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CONCRETE MIX DESIGN USING ABRAMS AND BOLOMEY METHODS
PublikacjaOne 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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Crack Resistance of Asphalt Concrete Subjected to Environmental Factors
PublikacjaThe paper presents an analysis of the influence of environmental factors on the cracking susceptibility of asphalt concrete resulting in a change in the durability of asphalt pavement. In order to assess the phenomenon, laboratory tests were carried out taking into account the destructive effects of moisture, freeze-thaw cycle and long-term ageing. The influence of both factors occurring simultaneously was also verified. Due to...
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Production of self-compacting concrete using limestone powder
PublikacjaAlthough there are visible signs of its gradual acceptance in North Africa through its limited use in construction, Libya has yet to explore the feasibility and applicability of self-compacting concrete (SCC) in new construction. The current study revolves around SCC made of locally available materials and the harsh environmental conditions. This paper deals with the investigation into the effect of the water to powder ratio and...
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Self-compacting grout to produce two-stage concrete
PublikacjaTraditional concrete (TC) is primarily composed of a mixture of cement, fine and coarse aggregates, and water. TC is made by mixing together all the components before placing them. Using non-traditional concrete (two-stage concrete) to solve and to eliminate the problem of the aggregate segregation which appears in TC and in the self-compacting concrete. Two-stage concrete (TSC) consists of two main components, namely the grout...
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The Effect of Fly Ash Microspheres on the Pore Structure of Concrete
PublikacjaThe fly ash microspheres (FAMs) formed during the mineral transformation stage in coal combustion are hollow spherical particles with a density less than water. This paper presents the results of X‐ray micro‐computed tomography and an automatic image analysis system of the porosity in the structure of hardened concrete with microspheres. Concrete mixtures with ordinary Portland cement and two substitution rates of cement by microspheres—5%...
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Experimental investigations on concrete beams reinforced with CFRP lamellas
PublikacjaPaper presents experimental investigation made on two concrete beams reinforced with internal Carbon Fibre Reinforced Polymer (CFRP) lamellas (i.e. strips, bands). The reinforcement geometrical arrangement was similar as in normal concrete beams reinforced with steel bars and stirrups. The beams were destroyed by the shear forces, as intended. Obtained load-carrying capacities were lower as expected: below 40% of a calculated value....
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The Effect of Water and Frost on Fatigue Life of Asphalt Concrete
PublikacjaThis paper presents testing of fatigue life of asphalt concrete that has been subjected to action of water and frost. Simulation of water and frost action was based on the original AASHTO T283 method and its modification. The original method was modified in such a way that instead of a single freeze-thaw cycle, 50 and 150 cycles were applied. Fatigue life was measured in the indirect tensile fatigue test in the Nottingham asphalt...
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Application of gpr method in diagnostics of reinforced concrete structures
PublikacjaThis 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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Shear resistance of low height precast concrete lintels
PublikacjaThe scope of the paper is to investigate analytically and determine experimentally the shear resistance of low height reinforced precast concrete lintels. The chosen procedures included in national and international standards applied for the design of structural concrete elements to an estimation of shear behaviour of reinforced concrete elements are described. The characteristic and designed shear strength of precast concrete...
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Comparison of calculated and measured thermal stresses in asphalt concrete
PublikacjaThe 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
PublikacjaThe 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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Experimental study of the post tensioned prestressed concrete corbels
PublikacjaThe results of experimental investigation of 6 symmetrical double prestressed corbels of variable shear span to depth ratio and variable location of prestressing bars are presented in the paper. The post ten- sioned corbels were prestressed with Macalloy 1030 bars of 25 mm in diameter. The results of the tests were compared with the cracking and load carrying capacity of corbels reinforced with passive reinforce- ment. As a result...
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Remote sensing and photogrammetry techniques in diagnostics of concrete structures
PublikacjaRecently laser scanning technologies become widely used in many areas of the modern economy. In the following paper authors show a potential spectrum of use Terrestrial Laser Scanning (TLS) in diagnostics of reinforced concrete elements. Based on modes of failure analysis of reinforcement concrete beam authors describe downsides and advantages of adaptation of terrestrial laser scanning to this purpose, moreover reveal under which...
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A concept of heterogeneous numerical model of concrete for GPR simulations
PublikacjaThe Ground Penetrating Radar (GPR) method, which is increasingly being used in the non-destructive diagnostics of reinforced concrete structures, often needs more accurate interpretation tools for analysis of experimental data. Recently, there has been growing interest in developing of various numerical models for exhaustive understanding of GPR data. This paper presents the concept of a heterogeneous numerical model of concrete,...
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Numerical mesoscopic analysis of fracture in fine-grained concrete
PublikacjaArtykuł omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu.
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Steel-fibrous concrete -experiments and a numerical discrete model
PublikacjaW 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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Modelling of concrete behaviour in uniaxial compression and tension with DEM.
PublikacjaW 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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Modelling of concrete using lattice and discrete element method
PublikacjaModelowanie betonu przy zastosowaniu metody siatkowej i metody elementów dyskretnych.
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3D DEM simulations of fracture in reinforced concrete beams
PublikacjaArtykuł 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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A constitutive model for concrete based on continuum theory with non-local softening coupled with eXtended Finite Element Method. Computational Modelling of Concrete Structures,
PublikacjaArtykuł 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?
PublikacjaThe 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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Experimental Study of the Resistance to Influence of Aggressive Liquids on Lightweight Concrete
PublikacjaIn light of the scientific research, the corrosion of concrete structures is one of the main problems that may reduce their durability due to the negative impact of the natural environment. The paper analyzes the influence of the type of component on the selected properties of lightweight concrete subjected to the influence of aggressive liquids. Four concrete mixes were prepared with a granular aggregate made of foamed glass (GEGA)...
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Deterioration and Protection of Concrete Elements Embedded in Contaminated Soil: A Review
PublikacjaCoating materials are considered one of the most antique materials of human civilization; they have been used for decoration and the protection of surfaces for millennia. Concrete structures—due to their permanent exposure to different types of environments and contaminants—require the use of coatings that contribute to its preservation by reducing the corrosion of its components (steel and aggregates). This article intends to...
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Concrete-filled FRP tubular members in marine and bridge structures
PublikacjaConcrete 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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SIGNIFICANT GUIDELINE FOR THE DAMAGE INDICES APPLIED TO REINFORCED CONCRETE STRUCTURES
PublikacjaIn 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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Application of guided waves in the evaluation of steel-concrete adhesive connection
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Concrete corrosion against penetration of mineral oil application of impregnants
PublikacjaOleje 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
PublikacjaThe 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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Estimation of the parameters of the discrete model of a steel–concrete composite beam
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An efficient and robust method for predicting asphalt concrete dynamic modulus
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