Influence of Aeration of Concrete on Acoustic Emission and Fracture Mechanical Parameters Obtained from Three-Point Bending Tests

2015 ◽  
Vol 1124 ◽  
pp. 237-242
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák ◽  
Petr Daněk ◽  
Zbyněk Keršner ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Mechanical Parameters ◽  
Bending Tests ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Acoustic Emission Sensors ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Mechanical Parameters

This paper examines the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with similar water-cement ratio, but one set of specimens was prepared from aerated concrete. The acoustic emission method is an experimental tool well suited for monitoring fracture processes in material. The typical parameters of acoustic emission signals were identified from the acoustic emission records for two different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The crack growth was continuously monitored using four acoustic emission sensors mounted on the specimen. The acoustic emission results are accompanied by selected fracture mechanical parameters determined via evaluation of load versus displacement diagrams recorded during three-point bending fracture tests.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

Correlation between Parameters of Acoustic Emission and Fracture Characteristics Obtained from Three-Point Bending Test

2015 ◽  
Vol 1124 ◽  
pp. 231-236
Author(s):  
Libor Topolář ◽  
Luboš Pazdera
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Emission Method ◽  
Fracture Characteristics ◽  
Three Point Bending ◽  
Experimental Tool ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission method is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

An Experimental Study on Acoustic Emission Signals during the Three-Point Bending Fracture Test

2014 ◽  
Vol 1000 ◽  
pp. 281-284 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Hana Šimonová ◽  
Tomáš Vymazal ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Fracture Test ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Experimental Tool ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Much has been said in literature about the fracture energy of concrete and its importance. Acoustic emission is an experimental tool well suited for monitoring fracture processes. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviours. The results obtained in the laboratory are useful to understand the various stages of micro-cracking activity during the fracture process in quasi-brittle materials such as concrete and extend them for field applications.

The Effect of Concrete Quality on the Acoustic Emission Parameters during Three-Point Bending Fracture Test

2014 ◽  
Vol 897 ◽  
pp. 149-152 ◽  
Author(s):  
Michal Matysík ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Tomáš Vymazal ◽  
Iveta Plšková
Keyword(s):  
Acoustic Emission ◽  
Large Scale ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Fracture Test ◽  
Opening Displacement ◽  
Three Point Bending ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture

Acoustic emission is an experimental tool well suited for monitoring fracture processes. The paper presents experiment focused on analysing acoustic emission signals captured during three-point bending fracture test of specimens of concrete. Quantitative acoustic emission techniques were used to measure micro fracture properties. For three different concrete mixtures typical acoustic emission patterns were identified in the acoustic emission records to further describe the under-the-stress behaviour and failure development. If we have a better understanding of the relationships between micro structural events and macroscopic behaviour we can better formulate predictive models for large-scale structural performance and reliability. An understanding of microstructureperformance relationships is the key to true understanding of material behaviours. Three-point bending fracture tests were conducted on these specimens and load versus crack mouth opening displacement (Load-CMOD) diagrams were recorded during the testing.

Evaluation of Three-Point Bending Fracture Tests of Selected Concrete: Crack Initiation and Acoustic Emission Parameters

2017 ◽  
Vol 259 ◽  
pp. 58-63
Author(s):  
Hana Šimonová ◽  
Libor Topolář ◽  
Ivana Havlíková ◽  
Michal Matysík ◽  
Petr Daněk ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Crack Initiation ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Opening Displacement ◽  
Unstable Crack ◽  
Three Point Bending ◽  
Damage Process ◽  
Fracture Tests ◽  
Bending Fracture

In this paper, authors concentrate attention on crack initiation and acoustic emission (AE) parameters obtained from records of three-point bending fracture tests on eight sets of concrete specimens with initial stress concentrator at the age of 28 days. Resistance to stable and unstable crack propagation was quantified via evaluation of load vs crack mouth opening displacement diagrams using Double-K fracture model. The AE technique was used to monitor damage process taking place during testing in specimens.

scholarly journals Acoustic Emission Analysis of Cement Mortar Specimens During Three Point Bending Tests

2016 ◽  
Vol 13 (12) ◽  
pp. 2283-2297 ◽  
Author(s):  
I. Stavrakas ◽  
D. Triantis ◽  
S.K. Kourkoulis ◽  
E.D. Pasiou ◽  
I. Dakanali
Keyword(s):  
Acoustic Emission ◽  
Cement Mortar ◽  
Emission Analysis ◽  
Bending Tests ◽  
Three Point Bending ◽  
Acoustic Emission Analysis

Fracture Response of Fine-Grained Cement-Based Composite Specimens with Special Inclusions

2019 ◽  
Vol 292 ◽  
pp. 63-68 ◽  
Author(s):  
Michal Vyhlídal ◽  
Iva Rozsypalová ◽  
Tomáš Majda ◽  
Petr Daněk ◽  
Hana Šimonová ◽  
...  
Keyword(s):  
Transition Zone ◽  
Interfacial Transition Zone ◽  
Mechanical Fracture ◽  
Three Point Bending ◽  
Fine Grained ◽  
Fracture Parameters ◽  
Edge Notch ◽  
Fracture Tests ◽  
Materials Used ◽  
Bending Fracture

This paper concerns research into the importance of the interfacial transition zone around inclusions of selected materials in fine-grained cement-based composite. Tests were performed on eight sets of prismatic test specimens. The sets differed in the inclusion materials used, which were placed at midspan above the initial central edge notch. The first was a reference set without any inclusion, the second contained a steel inclusion, four more contained different types of rock inclusion, the seventh contained an inclusion of extruded polystyrene, and the last contained a space of the same dimensions as that occupied by the inclusions in sets 2 to 7. The test specimens were subjected to three-point bending fracture tests at the age of (usually) 28 days. The fracture response was analysed by means of fracture mechanics theory, and apparent mechanical fracture parameters (modulus of elasticity, fracture toughness and fracture energy) were evaluated. The conclusion shows that a possible relationship exists between the differences in the mechanical fracture parameters of specimens with/without an inclusion and the existence of the interfacial transition zone.

Mechanical Fracture Properties of Cement Mortars with Diatomite in Relation to their Microstructure

2015 ◽  
Vol 1124 ◽  
pp. 57-62
Author(s):  
Pavla Rovnaníková ◽  
Hana Šimonová ◽  
Pavel Schmid ◽  
Jana Zahálková ◽  
Patrik Bayer ◽  
...  
Keyword(s):  
Elasticity Modulus ◽  
Hardened Cement ◽  
Mechanical Fracture ◽  
Fracture Properties ◽  
Three Point Bending ◽  
Cement Mortars ◽  
Edge Notch ◽  
Fracture Tests ◽  
Specific Fracture ◽  
Bending Fracture

The paper is focused on the mechanical fracture properties of hardened cement mortars in which Portland cement is partially replaced by reactive admixtures. These properties are evaluated in relation to the mortars’ microstructure through the size and content of pores. The cement in the mortars was partially replaced by a diatomite that contains amorphous SiO2. The three-point bending fracture tests were performed on beams with a central edge notch. The investigated mechanical fracture properties of the aforementioned cement-based composites included flexural strength, compressive strength, elasticity modulus, effective fracture toughness and specific fracture energy.

Acoustic Emission Evaluation of Thermal Barrier Coatings Using the Three Point Bending Test

1991 ◽  
Author(s):  
A. T. J. Verbeek ◽  
J. M. Houben ◽  
J. A. Klostermann
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Light And Electron Microscopy ◽  
Wide Band ◽  
Bending Test ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Bending Tests ◽  
Three Point Bending ◽  
Resonance Sensor

Thermal Barrier coatings were tested in three point bending tests, combined with acoustic emission evaluation. The test specimens consist of a 2 mm substrate with a 0.1 mm FeCrAlY bondcoat and a 0.3 mm ZrO2/Y2O3 93/7.8 weight % topcoat. Both the topcoat and the bondcoat were air plasma sprayed under varying conditions of the substrate cooling and the length of the plasma flame. On investigating the microstructure of the coatings, using light and electron microscopy, differences could be observed, due to the various spraying techniques. The coated specimens were tested in a tensile testing machine equiped with a special tool for three point bending tests. During bending, acoustic emissions from the coating were measured, using a two channel acoustic emission apparatus. Two types of AE sensors were used, namely a 150 kHz resonance sensor and a 0.1 −1 MHz wide band sensor. The various coatings show different AE patterns, especially the bondcoats which showed differences according to the spraying techniques. The use of wide band sensors had some advantages, however they were less sensitive than resonance sensors, they take signals that were received by the resonance ones. After testing, the specimens were prepared and microscopically investigated. Herewith it was possible to establish a relationship between the measured AE signal and the type of coating and coating failure.

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