scholarly journals Monitoring of the Impact of Lithium Nitrate on the Alkali–aggregate Reaction Using Acoustic Emission Methods

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Justyna Zapała-Sławeta ◽  
Grzegorz Świt
Keyword(s):  
Acoustic Emission ◽  
Initial Reaction ◽  
Lithium Nitrate ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Acoustic Activity ◽  
Initial Stage ◽  
Chemical Admixture ◽  
Different Characteristics ◽  
The Impact

The study analyzed the possibility of using the acoustic emission method to analyse the reaction of alkali with aggregate in the presence of lithium nitrate. Lithium nitrate is a chemical admixture used to reduce adverse effects of corrosion. The tests were carried out using mortars with reactive opal aggregate, stored under the conditions defined by ASTM C227. The acoustic activity of mortars with a corrosion inhibitor was referred to linear changes and microstructure of specimens in the initial reaction stages. The study found a low acoustic activity of mortars with lithium nitrate. Analysis of characteristic parameters of acoustic emission signals, combined with the observation of changes in the microstructure, made it possible to describe the corrosion processes. As the reaction progressed, signals with different characteristics were recorded, indicating aggregate cracking at the initial stage of the reaction, followed by cracking of the cement paste. The results, which were referred to the acoustic activity of reference mortars, confirmed that the reaction of opal aggregate with alkali was mitigated in mortars with lithium nitrate, and the applied acoustic emission method enabled the detection and monitoring of ASR progress.

scholarly journals Comparative analysis of the strength of restoration polymers of light polymerization for dental restoration using the acoustic emission method: part one

2021 ◽  
Vol 107 (3) ◽  
pp. 26-32
Author(s):  
V. Kukhta ◽  
◽  
V. Makeev ◽  
O. Kyrmanov ◽  
V. Skalsky ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Comparative Analysis ◽  
High Energy ◽  
Dental Restoration ◽  
Acoustic Emission Method ◽  
Local Loading ◽  
Emission Method ◽  
Composite Failure ◽  
Initial Stage ◽  
Ae Signals

Purpose. Comparative analysis of the strength of hybrid restoration composites of light polymerization during their local loading using the phenomenon of acoustic emission. The following restoration composites were studied: Latelux, Tetric N-Ceram, Charisma Classic. Results. It was determined that the nature of the destruction of all composites is the same: elastic-plastic at the initial stage of the load with a transition to brittle as its further growth. Three types of composite failure are observed: correct, incorrect and mixed. The first predominated during fracture under the action of local loading of the Latelux composite, for Tetric N-Ceram and Charisma Classic materials a mixed type of fracture is characteristic. Conclusions. Analysis of the parameters of the AE signals showed that the signals had the highest amplitude and energy when the Tetric N-Ceram composite was destroyed, and the lowest – Latelux. All dental composites are dominated by high-energy ductile-brittle and brittle fracture, which indicates the spread of micro- and macrocracks of various sizes in materials. Key words: polymer composites, strength, acoustic emission method.

scholarly journals Assessment of the technical condition of prefabricated elements using the acoustic emission method

2019 ◽  
Vol 28 (3) ◽  
pp. 356-365 ◽  
Author(s):  
Aleksandra Krampikowska ◽  
Anna Adamczak-Bugno
Keyword(s):  
Acoustic Emission ◽  
Prestressed Concrete ◽  
Technical Condition ◽  
Acoustic Emission Method ◽  
Material Degradation ◽  
Emission Method ◽  
Destructive Processes ◽  
Two Stages ◽  
The Impact ◽  
Concrete Elements

The article presents the results of tests using the acoustic emission method during the formation process of T-27 prestressed concrete beams. The studies included two stages. The first – testing the compressive strength of the cubic samples taken from the trial batch used for the production of beams together with the acquisition of acoustic emission signals. The second – measurements by acoustic emission, on the actual construction element during accelerated maturation of concrete caused by heating. The undertaking of the above subject results from the fact that this issue is of great importance when assessing the durability of reinforced concrete and pre-compressed elements in the aspect of the analysis of these structures in terms of durability. The impact of material degradation on the durability of the structure is difficult to appraise due to the lack of reliable results needed to estimate the durability of the selected statistical approach. However, the use of the acoustic emission method based on the identification of destructive processes creates the possibility of locating, identifying and monitoring the emerging and developing destructive processes affecting the durability of concrete elements.

scholarly journals The effect of nano-additive TiO2 on the failure process of self-compacting concrete assessed using the acoustic emission method

2018 ◽  
Vol 174 ◽  
pp. 02003
Author(s):  
Paweł Niewiadomski
Keyword(s):  
Acoustic Emission ◽  
Failure Process ◽  
Physical And Mechanical Properties ◽  
Test Method ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Emission Signal ◽  
Critical Stresses ◽  
Literature Reviews ◽  
The Impact

Due to the new challenges posed to engineering constructions, as well as the principles of sustainable development, many laboratories around the world are carrying out works to improve the basic structural material that is concrete. There has recently been a lot of interest in modifying concrete with nano-sized particles. Literature reviews indicate that their addition significantly improves the physical and mechanical properties of the concrete that was obtained with their use. Until now, there is no knowledge of the effect of nano-additives on the process of destroying temporarily compressed concrete. One test method that enables the parameters that describe the stress failure of concrete to be determined is the acoustic emission method. This work fills the gap in the literature and presents the results of the author's own research on the impact of the use of different amounts of nano-additive TiO2 on the failure process of selfcompacting concrete that was made solely on the basis of granite aggregate. The stress failure of the tested concrete was described using the stress levels (determined using the acoustic emission method) that initiate the cracking σi and critical stresses σcr that delimit the tested process. The descriptors that were used for this purpose are the rate of counts and the average effective value of the acoustic emission signal.

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 Friction Phenomena of Brake Pads by Acoustic Emission Method

2014 ◽  
Vol 7 (2) ◽  
pp. 703-709 ◽  
Author(s):  
Kazuho Mizuta ◽  
Yukio Nishizawa ◽  
Koji Sugimoto ◽  
Katsuya Okayama ◽  
Alan Hase
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
Brake Pads

scholarly journals Characterization of Fatigue Damage in 304L Steel by an Acoustic Emission Method

2013 ◽  
Vol 66 ◽  
pp. 651-660 ◽  
Author(s):  
A. Ould Amer ◽  
A.-L. Gloanec ◽  
S. Courtin ◽  
C. Touze
Keyword(s):  
Acoustic Emission ◽  
Fatigue Damage ◽  
Acoustic Emission Method ◽  
Emission Method ◽  
304L Steel
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