The Assessment of High-Temperature Degraded Concrete Specimens of Different Mixtures by Acoustic Emission Method during Three-Point Bending Test and Pulse Velocity Method in Comparison with Destructive Tests

2017 ◽  
Vol 908 ◽  
pp. 88-93 ◽  
Author(s):  
Libor Topolář ◽  
Richard Dvořák ◽  
Luboš Pazdera
Keyword(s):  
Acoustic Emission ◽  
Building Materials ◽  
Pulse Velocity ◽  
Bending Test ◽  
Structural Components ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Live Loads ◽  
Non Destructive

One of the advantages of concrete over other building materials is its inherent fire-resistive properties. The concrete structural components still must be able to withstand dead and live loads without collapse even though the rise in temperature causes a decrease in the strength and modulus of elasticity for concrete and steel reinforcement. In addition, fully developed fires cause expansion of structural components and the resulting stresses and strains must be resisted. This paper reports the results of measurements by Acoustic Emission method during three-point bending test on concrete specimens. The Acoustic emission method is a non-destructive technique used widely for structural health monitoring purposes of structures. The sensors are mounted by beeswax on the surface of the material or structure to record the motion of the surface under the elastic excitation of the cracking sources. The concrete specimens were heated in a programmable laboratory furnace at a heating rate of 5 °C/min. The specimens were loaded at six temperatures, 200 °C, 400 °C, 600 °C, 800 °C, 1000 °C, and 1200 °C maintained for 60 minutes. The results are obtained in the laboratory.

Three-Point Bending Test Evaluation of Concrete Specimens by Non-Traditional Analysis of Acoustic Emission Method

2016 ◽  
Vol 837 ◽  
pp. 198-202
Author(s):  
Luboš Pazdera ◽  
Libor Topolář ◽  
Tomáš Vymazal ◽  
Petr Daněk ◽  
Jaroslav Smutny
Keyword(s):  
Acoustic Emission ◽  
Signal Analysis ◽  
Measurement Data ◽  
Bending Test ◽  
Test Evaluation ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Time Frequency ◽  
Emission Signal

The aim of the paper is focused on the analysis of the mechanical properties of the concrete specimens with plasticizer at three point bending test by the signal analysis of the acoustic emission signal. The evaluations were compared the measurement and the results obtained with theoretical presumptions. The Joint Time Frequency Analysis applied on measurement data and its evaluation is described. It is well known that the Acoustic Emission Method is a very sensitive method to determine active cracks into structure. However, evaluation of acoustic emission signals is very difficult. A non-traditional method was used to signal analysis of burst acoustic emission signals recorded during three point bending test.

Evaluation of Acoustic Emission Events Generated at Three Point Bending of Different Concrete Specimens by Spectral Analysis

2016 ◽  
Vol 258 ◽  
pp. 485-488
Author(s):  
Lubos Pazdera ◽  
Libor Topolář ◽  
Petr Daněk ◽  
Jaroslav Smutny ◽  
Karel Mikulasek
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Direct Evaluation ◽  
Cement Ratio ◽  
Three Point Bending ◽  
Time Frequency ◽  
Frequency Domains ◽  
The Individual

The paper aims to the determine of the mechanical properties of the concrete specimens at three-point bending test by application of the Acoustic Emission Method. Recorded acoustic emission events generated during three-point loading have been chosen. Some frequency and joint time-frequency methods are applied to these records. Time series as acoustic emission events may be analyzed in the time, frequency, and/or time-frequency domains. The selection is based on the type of the signal in question, on the type of analysis to be used or the result achieved. In many applications, direct evaluation of the time-amplitude representation is neither easy nor advantageous. The individual mixtures were different in cement dosage and water-cement ratio based on how much the amount of cement was increased while maintaining consistency S2 according to EN 206.

Nondestructive Testing and Structural Condition Monitoring of Mechanical Cables

1993 ◽  
Vol 46 (4) ◽  
pp. 133-138 ◽  
Author(s):  
Patricio A. A. Laura
Keyword(s):  
Acoustic Emission ◽  
Nondestructive Testing ◽  
Condition Monitoring ◽  
Structural Condition ◽  
Non Destructive Testing ◽  
Acoustic Emission Method ◽  
Testing Methods ◽  
Emission Method ◽  
Destructive Testing ◽  
Non Destructive

This article concerns the problem of evaluating the `structural health’ of cables or ropes by means of non-destructive testing methods. Special emphasis is placed upon electromagnetic techniques and the acoustic emission method.

scholarly journals Effect of Freeze–Thaw Cycling on the Failure of Fibre-Cement Boards, Assessed Using Acoustic Emission Method and Artificial Neural Network

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2181 ◽  
Author(s):  
Tomasz Gorzelańczyk ◽  
Krzysztof Schabowicz
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Acoustic Emission ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Freeze Thaw ◽  
Fibre Cement ◽  
Artificial Neural ◽  
Building Practice

This paper presents the results of investigations into the effect of freeze–thaw cycling on the failure of fibre-cement boards and on the changes taking place in their structure. Fibre-cement board specimens were subjected to one and ten freeze–thaw cycles and then investigated under three-point bending by means of the acoustic emission method. An artificial neural network was employed to analyse the results yielded by the acoustic emission method. The investigations conclusively proved that freeze–thaw cycling had an effect on the failure of fibre-cement boards, as indicated mainly by the fall in the number of acoustic emission (AE) events recognized as accompanying the breaking of fibres during the three-point bending of the specimens. SEM examinations were carried out to gain better insight into the changes taking place in the structure of the tested boards. Interesting results with significance for building practice were obtained.

scholarly journals Identification of the Degree of Degradation of Fibre-Cement Boards Exposed to Fire by Means of the Acoustic Emission Method and Artificial Neural Networks

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 656 ◽  
Author(s):  
Krzysztof Schabowicz ◽  
Tomasz Gorzelańczyk ◽  
Mateusz Szymków
Keyword(s):  
Neural Networks ◽  
Acoustic Emission ◽  
Artificial Neural Networks ◽  
Bending Strength ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Three Point Bending ◽  
Fibre Cement ◽  
Artificial Neural ◽  
Degree Of Degradation

This paper presents the results of research aimed at identifying the degree of degradation of fibre-cement boards exposed to fire. The fibre-cement board samples were initially exposed to fire at various durations in the range of 1–15 min. The samples were then subjected to three-point bending and were investigated using the acoustic emission method. Artificial neural networks (ANNs) were employed to analyse the results yielded by the acoustic emission method. Fire was found to have a degrading effect on the fibres contained in the boards. As the length of exposure to fire increased, the fibres underwent gradual degradation, which was reflected in a decrease in the number of acoustic emission (AE) events recognised by the artificial neural networks as accompanying the breaking of the fibres during the three-point bending of the sample. It was shown that it is not sufficient to determine the degree of degradation of fibre-cement boards solely on the basis of bending strength (MOR).

Acoustic Emission Method for Monitoring Corrosion Reactions

CORROSION ◽  
1976 ◽  
Vol 32 (4) ◽  
pp. 121-126 ◽  
Author(s):  
T. W. RETTIG ◽  
M. J. FELSEN
Keyword(s):  
Acoustic Emission ◽  
Non Destructive Testing ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Destructive Testing ◽  
Corrosion Reaction ◽  
Reaction Processes ◽  
Non Destructive ◽  
Corrosion Research

Abstract There is a continuing need for new test techniques to follow corrosion reaction processes and to predict long-term materials performance in aggressive environments. Additionally, there is a growing awareness of the importance of applying non-destructive inspection to determine the presence of corrosion in non-visible areas of equipment and structures. The possibilities of utilizing acoustic emission for a broad range of applications in the study of these problems were explored. Proprietary methods were developed to follow corrosion reactions and to monitor corrosion of simulated and actual structures. These experiments point out the applicability of acoustic emission as a sensitive new tool for corrosion research and non-destructive testing (NDT) in corrosion prone structures and equipment.

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.

Parameters of Acoustic Emission Signals Obtained During the Setting and Hardening of Concrete Mixtures with Different Water-Cement Ratio

2016 ◽  
Vol 837 ◽  
pp. 152-156 ◽  
Author(s):  
Libor Topolář ◽  
Kristýna Timcakova ◽  
Petr Misak ◽  
Luboš Pazdera
Keyword(s):  
Acoustic Emission ◽  
Concrete Structure ◽  
Building Materials ◽  
Building Structures ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Destructive Testing ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Concrete Hardening

Concrete hardening and setting processes are the most critical phases during construction work, influencing the properties of concrete structure. For this reason applying non-destructive testing in the early age of concrete lifetime can be useful. Acoustic emission method is a powerful tool for determination of lifetime concrete structures. Nevertheless, its application in civil engineering area is not easy because many building structures are inhomogeneous. This method can describe material changes during concrete lifetime. Acoustic Emission Method monitors concrete structure continuously. Changes in the whole concrete structure are recorded. The acoustic emission phenomenon is directly associated with nucleation of cracks in building materials, therefore the changes result from the volumetric expansion causing formation micro and macro cracking in structure, which we can recognize. Application of Acoustic Emission Method during concrete hardening and setting with different water-cement ratio will be the aim of this article and his influence on parameters of acoustic emission. A comprehension of microstructure-performance relationships is the key to true understanding of material behaviour.

Observation of the Development of the Elastic Modulus and Strength in a Polymer-Cement Mortar Using the Acoustic Emission Method

2018 ◽  
Vol 272 ◽  
pp. 76-81
Author(s):  
Dalibor Kocáb ◽  
Libor Topolář ◽  
Barbara Kucharczyková ◽  
Petr Pőssl ◽  
Michaela Hoduláková
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Elastic Modulus ◽  
Modulus Of Elasticity ◽  
Cement Mortar ◽  
Resonance Method ◽  
Ultrasonic Pulse Velocity ◽  
Pulse Velocity ◽  
Acoustic Emission Method ◽  
Emission Method

The paper describes an experiment focused on observing the development of the elastic modulus and compressive strength in a polymer-cement mortar during the first 28 days of aging. The specimens (aged 3 and 28 days) were tested for the static and dynamic modulus of elasticity using two methods – the ultrasonic pulse velocity test and the resonance method. During the test of the modulus of elasticity in compression the mortar’s behaviour was also examined by means of the acoustic emission method, which is based on the recording of mechanical pulses caused by dilation waves generated by microcracks that form during loading. The outcome of the experiment is an evaluation of the polymer-cement mortar’s behaviour in terms of the development of its elastic modulus and compressive strength as well as in terms of the material’s acoustic response during loading.

scholarly journals Quality control of hardening technologies using the acoustic emission method

2021 ◽  
Vol 266 ◽  
pp. 04004
Author(s):  
E.V. Grigoriev ◽  
A.G. Palaev ◽  
T.S. Golikov ◽  
V.V. Nosov
Keyword(s):  
Quality Control ◽  
Acoustic Emission ◽  
Service Life ◽  
Experimental Research ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Industrial Facilities ◽  
Non Destructive

The ways of increasing the reliability and service life of industrial facilities are considered. The types of hardening technologies and methods of their control are analyzed. An approach that makes it possible to evaluate the quality of hardening technologies based on the registration of acoustic emission (AE) is described. The results of experimental research on the quality of three types of strengthening technologies are presented and the effectiveness of the proposed approach is shown. The obtained results can be used to assess hardening technologies at real facilities in a non-destructive way.

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