Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (38)
- Zeitschriftenartikel (24)
- Vortrag (21)
- Beitrag zu einem Sammelband (10)
- Forschungsbericht (5)
- Posterpräsentation (4)
- Forschungsdatensatz (2)
- Sonstiges (1)
Schlagworte
- Schallemission (14)
- Acoustic emission (12)
- Beton (11)
- Concrete (7)
- Cracks (6)
- Spannstahlbruch (6)
- Acoustic emission analysis (5)
- Brücke (5)
- Rissbildung (5)
- Spannbeton (5)
- Alkali-activated materials (4)
- Digital image correlation (4)
- Fugen (4)
- Non-destructive testing (4)
- Nondestructive testing (4)
- Optische Verformungsanalyse (4)
- Schallemissionsanalyse (4)
- Autogenes Schwinden (3)
- Baustoffe (3)
- Bending (3)
- Ermüdung (3)
- Fatigue (3)
- Marble (3)
- SHCC (3)
- Stahlbeton (3)
- Stereophotogrammetry (3)
- Tension (3)
- Tragverhalten bei Biegebeanspruchung (3)
- Ultrasonic testing (3)
- 60 °C-Betonversuch (2)
- Accelerated concrete prism test (2)
- Acoustic Emission Analysis (2)
- Adhesive failure (2)
- Alkali-Kieselsäure-Reaktion (2)
- Automated expansion measurement (2)
- Betonfahrbahndecke (2)
- Brückenmonitoring (2)
- Building Materials (2)
- Capability evaluation (2)
- Cementitious composites (2)
- Climate (2)
- Cohesive failure (2)
- Concrete Beam (2)
- Cracking (2)
- Cultural heritage (2)
- Dauerhaftigkeit (2)
- Digital Image Correlation (2)
- Durability evaluation (2)
- Ermüdungsverhalten (2)
- Fahrbahnbeläge (2)
- Faseroptik (2)
- Fiber reinforcement (2)
- Fire proofing (2)
- Fotogrammetrie (2)
- Funktionsfähigkeit (2)
- Geopolymers (2)
- High-strength concrete (2)
- Hochfester Beton (2)
- Hydratation (2)
- Marble sculptures (2)
- Mechanical characteristics (2)
- Multiple cracking (2)
- Numerical simulation (2)
- Offshore (2)
- Pavement joints (2)
- Performance (2)
- Quantifizierung realer Verformungen (2)
- Rehabilitation (2)
- Repair (2)
- Schlossbrücke (2)
- Schädigung (2)
- Spalling (2)
- Spannbetonbrücke (2)
- Strain-hardening (2)
- Superimposed loading (2)
- System evaluation (2)
- System test method (2)
- Tensile strength (2)
- Ultrasound (2)
- Unikaler Prüfstand (2)
- Zerstörungsfreie Prüfung (2)
- 3D computed tomography (1)
- 60 °C-CPT (1)
- AKR (1)
- ASR (1)
- ASR expansion monitoring (1)
- ASR modelling (1)
- Accelerated testing (1)
- Acoustic Emission (1)
- Acoustic emission monitoring (1)
- Acoustic emission testing (1)
- Advanced measurement setup (1)
- Alkali silica reaction (1)
- Alkali-silica reaction (1)
- Alkali–silica reaction (1)
- Asphaltdeckschicht (1)
- Auslaugung (1)
- Autobahn (1)
- Automated testing (1)
- Automatische Dehnungsmessung (1)
- Automatisierte Dehnungsmessung (1)
- Bauwerkssicherheit (1)
- Bituminous compounds (1)
- Brandverhalten (1)
- Bruchlastwechselzahlen (1)
- Brückeninfrastruktur (1)
- Building materials (1)
- CIF- und CDF-Prüfung (1)
- Chloride migration (1)
- Civil engineering (1)
- Climate data (1)
- Climatic impact (1)
- Coda wave interferometry (1)
- Coda wave interferometry Beton (1)
- Compressive Concrete Strength (1)
- Compressive Cyclic loading (1)
- Compressive concrete strength (1)
- Compressive cyclic loading (1)
- Computertomografie (1)
- Concrete Prism Test at 60 °C (1)
- Concrete beam (1)
- Concrete pavement (1)
- Concrete pavements (1)
- Concrete prism test (1)
- Continuous monitoring (1)
- Corrosion potential (1)
- Crack Detection (B) (1)
- Crack formation (1)
- Crack propagation (1)
- Damage analysis (1)
- Damage evolution (1)
- Damages (1)
- Datenmanagement (1)
- Debonding Mechanism (1)
- Degradation (1)
- Denkmalpflege (1)
- Destructive testing (1)
- Deterioration (1)
- Digitalisierung (1)
- Distributed fibre optic sensor (1)
- Druckschwellenversuch (1)
- Electrical resistivity (1)
- Embedded sensors (1)
- Energiebilanz (1)
- Energy (1)
- Existing structure (1)
- Expansion modelling (1)
- FAIR-Prinzip (1)
- Fahrbahnbefestigungen (1)
- Failure (1)
- Fasern (1)
- Faserverstärkter Beton (1)
- Fiber (1)
- Fibre Reinforcement (E) (1)
- Fibre bragg grating (1)
- Fibre optic sensors (1)
- Fibre pull-out (1)
- Field validation (1)
- Fire (1)
- Fire exposure (1)
- Fire protection (1)
- Fire resistance (1)
- Fog chamber (1)
- Fracture (1)
- Freeze-thaw (1)
- Frost- und Frost-Tausalz-Prüfung (1)
- Frühe Rissbildung (1)
- Geräteentwicklung (1)
- Grouted Connection (1)
- Grouted connection (1)
- Grouted connections (1)
- Heat exposure (1)
- Heat resistance (1)
- High temperature behaviour (1)
- Hochduktiler Beton (1)
- Hochleistungsbeton (1)
- Hochleistungsbetone (1)
- Hydraulic engineering structures (1)
- Innovative Messverfahren (1)
- Innovative Prüftechnik (1)
- Innovative measurement technology (1)
- Interlaboratory comparison (1)
- Joint sealing systems (1)
- Kapillardruck (1)
- Klima (1)
- Kontinuierliche Lagerung (1)
- Korrosion (1)
- Kulturelles Erbe (1)
- Landstraße (1)
- Leaching of alkalis (1)
- Length change (1)
- Load quantification (1)
- Maintenance (1)
- Marble decay (1)
- Marble deterioration (1)
- Marble weathering (1)
- Marmor (1)
- Marmorverwitterung (1)
- Materialdaten (1)
- Mechanical properties (1)
- Metadaten (1)
- Microcracking (1)
- Microcracking (B) (1)
- Microstructure (1)
- Mikrorissbildung (1)
- Mineralstoffe (1)
- Mitigation strategies (1)
- Mixture composition (1)
- Monitoring (1)
- Naturstein (1)
- Non destructive testing (1)
- Non-Destructive Testing (1)
- Numerical simulations (1)
- Ontologie (1)
- Optical deformation analysis (1)
- Optical deformation measurement (1)
- PVA-Fasern (1)
- Performance design for joint systems (1)
- Performance-orientierte Stoff- und Systemkennzeichnung (1)
- Photogrammetrie (1)
- Photogrammetry (1)
- Plastic shrinkage cracking (1)
- Plastische Fugenvergussmassen (1)
- Plastisches Schwinden (1)
- Polymer Fibres (1)
- Prestressed concrete bridge (1)
- Probekörpergeometrien (1)
- Probengeometrie (1)
- Probengröße (1)
- Protective winter cover (1)
- Prüfverfahren (1)
- Pull-Out Behaviour (1)
- Quasi non-destructive assessment (1)
- Radar (1)
- Real scale test (1)
- Rebound Hammer (1)
- Rebound hammer (1)
- Rebound number (1)
- Reflexionsvermögen (1)
- Reinforced concrete beam (1)
- Residual strain (1)
- Richtlinie (1)
- Road pavement (1)
- Röntgen-3D-CT (1)
- Schadensanalyse (1)
- Schallemissionsanlayse (1)
- Schallemissionsprüfung (1)
- Schrumpfrisse (1)
- Schädigungsprozesse (1)
- Self-desiccation shrinkage (1)
- Service life (1)
- Simulation (1)
- Size effect (1)
- Slenderness effect (1)
- Sommer (1)
- Sonneneinstrahlung (1)
- Spanndrahtbruch (1)
- Spannstahl (1)
- Spannungsrisskorrosion (1)
- Stahlfaserbeton (1)
- Static loading (1)
- Steel corrosion (1)
- Steel fibres (1)
- Stereofotogrammetrie (1)
- Stochastische Subspacebasierte Schadensdetektion (1)
- Strengthening strategy (1)
- Stress (1)
- Stress corrosion cracking (1)
- Structural health monitoring (SHM) (1)
- Sustainable joint sealing (1)
- Tensile Properties (C) (1)
- Tensile loading (1)
- Transducers (1)
- Transmission (1)
- UHPFC (1)
- UHPFRC (1)
- Ultra sound (1)
- Ultraschall (1)
- Ultraschall-Transmission (1)
- Ultrasonic Pulse Velocity (1)
- Ultrasonic and ray (1)
- Ultrasonic pulse velocity (1)
- Ultrasonic velocities (1)
- Ultrasonic velocity (1)
- Ultrasonic waves (1)
- Ultrasound wave velocities (1)
- Verformung (1)
- Verwitterung (1)
- Water absorption (1)
- Weathering processes (1)
- Weathering sensitivity (1)
- Winter (1)
- Winter cover (1)
- Winter shelters (1)
- Wintereinhausung (1)
- Wintereinhausungen (1)
- Wire break (1)
- Wissengraph (1)
- Wärmeabstrahlung (1)
- Wärmebilanz (1)
- Wärmekapazität (1)
- Wärmeleitfähigkeit (1)
- Zerstörungsarme und zerstörungsfreie Prüfverfahren (1)
- Zugbeanspruchung (1)
- Zugversuch (1)
- Zusatzstoffe (1)
- alkali-silica-reaction (1)
- concrete pavements (1)
- damage monitoring (1)
- fatigue (1)
- µ-3D-CT (1)
Organisationseinheit der BAM
- 7 Bauwerkssicherheit (39)
- 7.1 Baustoffe (38)
- 7.4 Baustofftechnologie (11)
- 8 Zerstörungsfreie Prüfung (9)
- 7.2 Ingenieurbau (6)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (5)
- 7.0 Abteilungsleitung und andere (4)
- 7.5 Technische Eigenschaften von Polymerwerkstoffen (3)
- 7.7 Modellierung und Simulation (3)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (3)
Paper des Monats
- ja (1)
Eingeladener Vortrag
- nein (21)
This study evaluates the sensitivity of embedded ultrasonic sensors to detect propagating cracks within concrete. Because of the sensors constant coupling to the medium, highly sensitive data analysis techniques, such as the correlation between signals and their attenuation, are applied to detect changes in the signal due to propagating cracks.
The accuracy of the detected onset of the crack is evaluated with the nondestructive testing methods acoustic emission and Digital Image Correlation. It shows that with embedded ultrasonic sensors crack propagation can be detected before it is visible on the surface of the concrete.
Self-compacting concrete typically contains a higher content of powder materials than normal concrete. Furthermore it is assumed that the use of superplasticizers yields a more homogenous microstructure in the hardened paste. Both aspects generate a very dense microstructure, which can be assumed to cause material behaviour that differs from than normal concrete when it is exposed to elevated temperatures. However, the paste volumes in SCC can vary significantly based on the mixture composition. At a low paste volumes SCC can be very similar to normal concrete at hardened state while it can vary greatly at higher paste volumes. Since the high temperature behaviour of concrete is strongly affected by the different physical behaviour of the paste and the aggregates, it is likely that the high temperature behaviour is consequently strongly affected by the ratio of these mixture components. In the present study different SCC mixtures were observed with similar mechanical properties, but with significantly differing paste to aggregate ratios. Based on observations of the heat evolution at the fire exposed surface and at different depths inside the specimens as well as based on photogrammetric observations of the spalled dimensions, the results indicate that with increasing paste volumes the heat conductivity is reduced and as a result concrete with higher paste to aggregate ratios shows less spalling.
Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide.
The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented.
In recent years the German motorway network has seen an increase in the occurrence of damage to concrete road surfaces which can be attributed to the alkali-silica reaction (ASR). In view of the often drastically reduced life expectancy of road surfaces due to ASR, research activity in this field has notably increased. Alongside preventative measures in concrete technology, the main research focus up to now has been the development of performance-oriented testing procedures for ASR prevention. This included more specifically the accelerated simulation of climatic effects and external alkali penetration on road surfaces. The effects of mechanical pre-damage resulting from cyclic traffic loading and climatic impact had previously not been taken into consideration. Since 2011, the five-partner research group 1498 sponsored by the German Research Foundation (DFG) has been pursuing research on how simultaneous cyclic loading and external alkali penetration impacts destructive ASR in road surface concretes. The depiction of the myriad degradation and transport processes necessary for an understanding of these effects requires close interaction between experiments and their multi-scale modelling. This paper aims to focus on the aforementioned experiments by means of innovative testing techniques. The research is founded on a series of cyclic fatigue tests performed on large-format beams, both with and without previous application of a sodium chloride (NaCl) solution, with simultaneous tracking of crack development. Subsequently, smaller test specimens were extracted from the pre-damaged beams for further experiments. These included the spatial visualization and quantification of fatigue-induced cracks using micro X-ray 3D-computed tomography (3D-CT). Additionally, the effects of fatigue-induced cracks on alkali transport were investigated using Laser-Induced Breakdown Spectroscopy (LIBS). Subsequent storage of the small-format test specimens, with and without cyclic pre-damage, in an ASR-conducive environment then provided initial findings on the influence of fatigue-induced predamage on the ASR.