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Wyniki wyszukiwania dla: GRID REINFORCEMENT, FATIGUE OF ASPHALT PAVEMENTS, FOUR-POINT BENDING TEST, CRACK PROPAGATION, REFLECTIVE CRACKING
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Micro-cracking pattern recognition of hybrid CNTs/GNPs cement pastes under three-point bending loading using acoustic emission technique
PublikacjaThe generation of microcracks has an important influence on the behaviour of concrete structures. In this study, the acoustic emission (AE) technique was used to investigate the fracture phenomena and micro-cracking behavior of hybrid carbon nanotubes (CNTs, the 1-D allotrope of carbon atoms) and graphene nanoplatelets (GNPs, 2D monolayer of sp2-hybridized carbon atoms), cement composites under three-point bending loading. In...
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Influence of selected WMA additives on viscoelastic behaviour of asphalt mixes and pavements
PublikacjaWarm mix asphalt additives are effective in decreasing production, laying and compaction temperatures of asphalt mixes. However, there are still questions concerning influence of warm mix additives on properties of asphalt mixes and pavement performance. This paper presents results of the comprehensive research of viscoelastic behaviour of asphalt mixes and pavement structures with layers made with warm mix asphalt additives at...
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Local and global response of sandwich beams made of GFRP facings and PET foam core in three point bending test
PublikacjaIn the paper behaviour of laminated sandwich beams (FRP face sheet – PET foam core – FRP face sheet) subjected to three point bending is studied. The paper aim is to find practical descriptions enabling effective and accurate estimation of the elastic response, damage and failure of the beams, basing on experiments and static calculations. Therefore a number of tests are described, that were done on laminated coupons and foam specimens...
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Development and application of asphalt binder relaxation test in different dynamic shear rheometers
PublikacjaIn this study, a novel relaxation test is proposed to evaluate asphalt binder low temperature properties using a Dynamic Shear Rheometer (DSR) with parallel plates of 4 mm in diameter. Three rheometers from three different manufacturers are used to analyze seven asphalt binders. Different material parameters are derived which are useful to evaluate and discriminate different asphalt binders. Test results of all three instruments...
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Relationship between Fatigue Condition of Asphalt Pavements and Deflection Lag from Traffic Speed Deflectometer
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublikacjaThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...
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The influence of reinforcement on load carrying capacity and cracking of the reinforced concrete deep beam joint
PublikacjaThe paper presents the results of experimental research of the spatial reinforced concrete deep beam systems orthogonally reinforced and with additional inclined bars. Joint of the deep beams in this research was composed of the longitudinal deep beam with a cantilever suspended at the transversal deep beam. The cantilever deep beam was loaded throughout the depth and the transversal deep beam was loaded at the mid-span by longitudinal...
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Evaluation of Low Temperature Properties of Rubberized Asphalt Mixtures
PublikacjaThe paper presents low-temperature test results of asphalt mixtures designed with use of bitumen modified by crumb rubber and also SBS polymer. Laboratory tests were conducted on two types of asphalt mixtures for wearing course – stone matrix asphalt (SMA 8) and porous asphalt (PA 8). This paper presents results of the following laboratory tests at low temperatures: TSRST test, three point bending creep test, fracture toughness...
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Prediction of corrosion fatigue crack propagation life for welded joints under cathodic potentials
PublikacjaPrzy ochronie katodowej poniżej potencjału optymalnego obserwuje się przyspieszenie propagacji pęknięcia korozyjno-zmęczeniowego w porównaniu do konstrukcji nie chronionej. Zaproponowano własną formułę empiryczną na wpływ potencjału ochronnego na prędkość propagacji pęknięcia oraz własny wzór na [delta]K w złączu pachwinowym. Wyprowadzono wzór na krzywą ''S-Np'' (naprężenie - długość okresu propagacji pęknięcia). Zaprezentowana...
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Analysis of effect of overloaded vehicles on fatigue life of flexible pavements based on weigh in motion (WIM) data
PublikacjaOverloaded vehicles have a significant impact on pavement fatigue life and distress. As the studies show, the phenomena intensify when the control of traffic is poor. The paper presents the results of the research including analysis of weigh in motion data from eight stations and analysis of asphalt pavement fatigue caused by mixed traffic. Distributions of vehicles axles load including the multiple axles effects are presented....
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Impact of reclaimed asphalt pavement (RAP) on low-temperature properties of asphalt concrete
PublikacjaHot mix recycling is a practice which enables reusing materials from old asphalt pavements. Current Polish regulations allow usage of RAP only for binder and base courses, and its amount is limited. Asphalt mixtures with RAP material have to fulfil requirements stated for typical asphalt mixtures. The research presents low-temperature properties of twelve different asphalt concretes with RAP material, determined using three-point...
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A new viscoelastic method of calculation of low-temperature thermal stresses in asphalt layers of pavements
PublikacjaThe paper presents a new method of calculation of thermal stresses in asphalt layers of pavements induced by cooling or heating. The method, developed by the author, is based on the analytical solution for the linear viscoelastic Burgers model extended numerically for the case of asphalt layers whose rheological parameters are strongly dependent on temperature. The coefficient of thermal expansion and Poisson’s ratio may optionally...
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Durability of Asphalt Concrete Subjected to Deteriorating Effects of Water and Frost
PublikacjaThe 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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Fractal dimension for bending–torsion fatigue fracture characterisation
PublikacjaFracture surfaces after biaxial fatigue tests were compared using fractal dimension for three types of metallic materials in smooth and notched specimens made of S355J2 and 10HNAP steels and 2017-T4 aluminium alloy, considering both proportional and nonproportional cyclic loading. High-resolution optical 3D measurement studies were performed on the entire fracture surface. A direct correlation between fractal dimension and fatigue...
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Coda wave interferometry in monitoring the fracture process of concrete beams under bending test
PublikacjaEarly detection of damage is necessary for the safe and reliable use of civil engineering structures made of concrete. Recently, the identification of micro-cracks in concrete has become an area of growing interest, especially using wave-based techniques. In this paper, a non-destructive testing approach for the characterization of the fracture process was presented. Experimental tests were made on concrete beams subjected to mechanical...
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FEM simulation of laminate failure in the three point bending
PublikacjaThe paper presents a FEM simulation of failure of laminate subjected to the three point bending. The numeri-cal model is based on the equivalent single layer approach with 6-paramater non-linear shell theory kinematics. It is implemented in the non-commercial FEM code. The failure initiation is detected with the use of Tsai-Wu criterion. After the failure onset the progressive failure process is modelled through the appropriate...
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Effect of interlayer bonding quality of asphalt layers on pavement performance
PublikacjaThe quality of interlayer bonding at the interfaces between the asphalt layers in flexible pavements affects the overall pavement performance. Lack or partial lack of interlayer bonding between asphalt layers can cause pavement's premature failures such as rutting, slippage of the wearing course, cracking or simply a reduction in the calculated fatigue life of the pavement structure. This paper shows the case studies of investigation...
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The impact of surface slope and calculation resolution on the fractal dimension for fractures of steels after bending-torsion fatigue
PublikacjaThe article presents the results of the fractal dimension measurements on the fatigue fracture surfaces of 10HNAP and S355J2 steels specimens after combined bending-torsion fatigue. For smooth and ring-notched specimens, three loading conditions were analyzed: (1) bending; (2) bending-torsion; and (3) torsion fatigue. Post-failure surface topography measurements were carried out on the entire fracture surfaces using an optical...
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The utilization of waste plastics in asphalt pavements: A review
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A Point Set Connection Problem for Autonomous Mobile Robots in a Grid
PublikacjaConsider an orthogonal grid of streets and avenues in a Manhattan-like city populated by stationary sensor modules at some intersections and mobile robots that can serve as relays of information that the modules exchange, where both module-module and module-robot communication is limited to a straight line of sight within the grid. The robots are oblivious and move asynchronously. We present a distributed algorithm that, given...
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Effect of selective laser treatment on initiation of fatigue crack in the main part of an undercarriage drag strut
PublikacjaThis paper presents the results of material characterization and a fatigue test conducted for a laser-re-melted drag strut used in an aircraft landing gear. The drag strut was re-melted with a CO2 laser beam. Eight re-melted paths were made in the form of spiral lines along the axis of the drag strut. Next, the drag strut was subjected to variable loads on a testing machine simulating loads occurring when an aircraft lands. The...
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Investigation of low-temperature cracking in newly constructed high-modulus asphalt concrete base course of a motorway pavement
PublikacjaThe paper presents the issue of low-temperature transverse cracks which have developed in newly constructed base courses made of high-modulus asphalt concrete mix (HMAC). Numerous transverse cracks developed in the analysed HMAC base during the winter season before the pavement was actually completed, both at the transverse joint locations and in the areas between them. This had not happened so far on such a scale during road construction...
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Corrigendum to “Fatigue life improvement using low transformation temperature weld material with measurement of residual stress” [Int. J. Fatigue 164 (2022) 107137]
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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The influence of combination of binding agents on fatigue properties of deep cold in-place recycled mixtures in Indirect Tensile Fatigue Test (ITFT)
PublikacjaThe publication presents fatigue properties of cold recycled mixtures for eight combinations of binding agents (cement and bituminous emulsion). Cold recycled mixtures were evaluated in Indirect Tensile Fatigue Test (ITFT) at the temperature of 20 C in controlled stress mode. As a function of horizontal stress, fatigue life is strongly influenced by combination of the binding agents. When fatigue life is analyzed as a function...
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Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue
PublikacjaThis paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and...
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Environmentally-Safe Cold Recycling of Asphalt Pavements in Poland
PublikacjaArtykuł przedstawia metodę recyklingu na zimno z zastosowaniem jednoczesnego dodatku cementu portlandzkiego i emulsji asfaltowej. Metoda przydatna do rehabilitacji zniszczonych nawierzchni drogowych. Warstwy po recyklingu charakteryzują się sztywnością i podatnością. Przedstawiono wyniki badań laboratoryjnych i terenowych.
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublikacjaDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublikacjaIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Fracture Surface Behavior of 34CrNiMo6 High-Strength Steel Bars with Blind Holes under Bending-Torsion Fatigue
PublikacjaThe present study evaluates the fracture surface response of fatigued 34CrNiMo6 steel bars with transverse blind holes subjected to bending with torsion loading. The analysis of the geometric product specification was performed by means of height parameters Sx, functional volume parameters Vx, and fractal dimension Df. Surface topography measurements were carried out using an optical profilometer with focus variation technology....
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Three-Dimensional Fractography for Conventional and Additive Manufactured Steels After Bending-Torsion Fatigue
PublikacjaIn this study, fracture surface topography parameters were measured to investigate the effects of multiaxial loading. In order to assess the metrological aspects of fracture for notched specimens made of high-strength steels processed by both conventional and additively manufacturing (AM) techniques, an optical surface profilometer was used. Three bending moment to torsion moment ratios (B/T) were studied, i.e. 2, 1 and 2/3. The...
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Crack propoagation in MgO-PSZ ceramic materials
PublikacjaThe properties of ceramic materials such as elevated hardness, high temperature capability, low coefficient of thermal expansion are of interest for rolling element materials. Widely used ceramic materials in engineering applications are silicon nitride, zirconia and alumina. The paper presents an experimental study of the fatigue life of MgO-PSZ ceramic material in lubricated contact with defined types of cracks. A ceramic angular...
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Accelerated Pavement Testing to Evaluate the Reinforcement Effect of Geogrids in Flexible Pavements
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Low noise poroelastic road pavements based on modified asphalt binder
PublikacjaTire/road noise is one of the most important environmental problems related to road traffic. As the most effective way to fight noise is reduction of sound emission from the source, a lot of work is being done to improve tire and road surfaces construction. This paper describes the first “road” results obtained within the SEPOR project, which is focused on developing a low noise poroelastic road surface based on bituminous binder....
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Wave propagation in plate structures for crack detection
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Wave propagation in plate structures for crack detection.
PublikacjaW pracy przedstawiono analizę propagacji fali poprzecznej w płycie z pęknięciem. Do modelowania zagadnienia zastosowano metodę elementów spektralnych.
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Propagation of in-plane waves in an isotropic panel with a crack
PublikacjaW pracy przedstawiono model tarczowego elementu spektralnego do analizy propagacji fali wzdłuznej w panelach z uszkodzeniami.
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Numerical simulation of asphalt mixtures fracture using continuum models
PublikacjaThe paper considers numerical models of fracture processes of semi-circular asphalt mixture specimens subjected to three-point bending. Parameter calibration of the asphalt mixture constitutive models requires advanced, complex experimental test procedures. The highly non-homogeneous material is numerically modelled by a quasicontinuum model. The computational parameters are averaged data of the components, i.e. asphalt, aggregate...
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On the crack front curvature in bonded joints
PublikacjaStandard tests of adhesively bonded specimens are likely to produce heterogeneous stress distribution along the crack front and its vicinity. High separation rate mode I dominated fracture test is performed.Observation of post mortem fractured surfaces with an optical microscope reveals characteristic features of mixed mode I/III fracture near the sides of the specimen but not in the middle. At first, finite elements calculations...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Multiaxial Fatigue Behaviour of SLM 18Ni300 Steel
PublikacjaFatigue behaviour of SLM 18Ni300 steel under proportional bending-torsion loading is studied. The fatigue tests are conducted under pulsating loading conditions using tubular specimens with a transversal circular hole. Three ratios of the normal stress to shear stress are considered, namely σ/τ=4,σ/τ=2 and σ/τ = 4/3. Crack initiation sites were found for two diametrically opposite points around the hole, whose locations are governed...
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Equivalent temperature for design of airport pavements using mechanistic-empirical methods
PublikacjaThe paper presents implementation of equivalent temperature for design of airport asphalt pavements. The calculation methods of equivalent temperature: the Shell method, the French method and method that use the Asphalt Institute fatique criteria were presented. An example of calculations of equivalent temperature for Gdansk Airport was introduced and discussed. It was shown that methods of calculation of equivalent temperature...
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Influence of Wood Moisture on Strength and Elastic Modulus for Pine and Fir Wood Subjected to 4-point Bending Tests
PublikacjaThe main purpose of this research paper was to determine the influence of the wood moisture on the strength and elastic modulus of pine and fir wood specimens subjected to the 4-point bending tests. Six bending tests for each wood species and for two different moisture level have been performed. Then, the advanced statistical analysis of the results has been carried out. On the basis of the obtained results, it has been noted that...
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Textile reinforced concrete members subjected to tension, bending, and in-plane loads: Experimental study and numerical analyses
PublikacjaTextile reinforced concrete has raised increasing research interest during the last years, mainly due to its potential to be used for freeform shell structures involving complex load situations. Yet, most experimental work has focused on test setups with primarily uniaxial loading. In the current work, such setups are complemented with a novel test setup of deep beams, including in-plane bending and shear. Further, nonlinear finite...
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Fatigue of titanium alloy Ti6Al4V with diamond structure obtained by Laser Power Bed Fusion method
PublikacjaThis paper presents the results of fatigue tests conducted on Ti6Al4V titanium alloy with diamond structure obtained by the Laser Power Bed Fusion method. Samples used in tests were printed with porosities: 81%, 73%, 50%, 34% and near-zero porosity. Samples were subjected to cyclic tests with a constant stress amplitude. The number of cycles until sample failure was registered. Obtained fatigue test results made it possible to...
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Fractal dimension for bending–torsion fatigue fracture characterisation
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Influence of compaction effectiveness on interlayer bonding of asphalt layers
PublikacjaThe paper presents the results of research on the interlayer bonding of asphalt layers compacted in the laboratory and in the field. To measure the interlayer bonding at a temperature of 20°C the Leutner test apparatus was used and load was applied at a rate of 50 mm/minute. Three types of interlayer interfaces were tested: no tack coat and tack coats made of two types of the pure bitumen emulsions. Four compaction techniques were...
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Ograniczenie trwałości skojarzeń ceramicznych w wyniku propagacji pęknięć powierzchniowych = Fatigue life limitation of ceramic materials due to surface crack propagation
PublikacjaPrzedstawiono krótką analizę literaturową dotyczącą mechanizmów propagacji pęknięć w materiałach ceramicznych oraz wyniki dotychczasowych badań doświadczalnych wybranych materiałów ceramicznych z uwzględnieniem wpływu pęknięć powierzchniowych na trwałość ceramicznych skojarzeń tocznych.
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Longitudinal wave propagation. Part II—Analysis of crack influence
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Longitudinal wave propagation. Part II, Analysis of crack influence
PublikacjaW pracy analizowano wpływ pęknięć zmęczeniowych na propagacje fali wzdłużnej w prętach. Opracowano nowe typy element ów spektralnych oparte na teorii elementarnej, Love'a, Mindlina i trójpostaciowej.
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Influence of aggregates angularity on the locking point of asphalt mixtures
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