To the Problems of Determination of Dynamic Elasticity Modules of Calcium Silicate Bricks by Means of Resonance Method

2014 ◽  
Vol 897 ◽  
pp. 139-143 ◽  
Author(s):  
Jiří Brožovský ◽  
Ámos Dufka
Keyword(s):  
Modulus Of Elasticity ◽  
Calcium Silicate ◽  
Building Materials ◽  
Resonance Method ◽  
Pulse Method ◽  
Ultrasonic Pulse ◽  
Test Methods ◽  
Test Method ◽  
Resonance Test ◽  
Accuracy Of Measurement

Modulus of elasticity of building materials can be determined in a static way (loading in a press) or by means of non-destructive test methods (ultrasonic pulse method and resonance method); the parameter is most frequently determined for concrete and both methods of determining elasticity modulus are codified in Standards. Elasticity characteristics of calcium silicate bricks were determined by means of resonance test method. Because the shape of calcium silicate bricks (a block with oblong foot) is different from the shape of test specimens for concrete (usually blocks with square foot), expected frequencies for verification of accuracy of measurement by resonance method were determined. Moisture content of calcium silicate bricks (water absorbing capacity is up to 12-14%) has influence on the value of resonance frequency. Difference between dynamic Young's modulus of elasticity from fundamental longitudinal and transverse resonant frequency is on average 2.8%.

Comparison of Dynamic Young's Modulus of Elasticity Values Measured by Ultrasonic Pulse and Resonance Methods

2015 ◽  
Vol 1100 ◽  
pp. 193-196
Author(s):  
Jiří Brožovský ◽  
Ámos Dufka
Keyword(s):  
Young’S Modulus ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Resonance Method ◽  
Pulse Method ◽  
Ultrasonic Pulse ◽  
Dynamic Young’S Modulus ◽  
Young’S Modulus Of Elasticity ◽  
Dynamic Young's Modulus ◽  
The Difference

Dynamic Young ́s modulus of elasticity can be determined by ultrasonic pulse method and resonance method. Because of the difference in the way of introducing tension into a test specimen, the values of modulus of elasticity differ. Dynamic Young ́s modulus of elasticity measured by ultrasonic pulse method is higher; the difference stated for concrete is 5 to 20%. It was found that the dynamic Young's modulus of elasticity of calcium silicate bricks and prisms measured by ultrasonic pulse method is on average higher by 9.5% than dynamic Young's modulus of elasticity measured by resonance method. If dynamic Young's modulus of elasticity is converted to static modulus of elasticity, this difference has to be taken into account by means of appropriate coefficient.

On the Issue of Safe Use of Fiber Cement Materials in the Buildings and Structures

2021 ◽  
pp. 35-41
Author(s):  
N.I. Konstantinova ◽  
◽  
N.V. Smirnov ◽  
O.V. Krivoshapkina ◽  
O.I. Molchadskiy ◽  
...  
Keyword(s):  
Building Materials ◽  
Protective Coatings ◽  
Fire Hazard ◽  
Thermal Exposure ◽  
Test Methods ◽  
Test Method ◽  
Sand Mixture ◽  
Industrial Buildings ◽  
Experimental Complex ◽  
Combustible Materials

Fiber cement finishing materials are widely used in the construction of industrial buildings and structures due to the complex of valuable operational properties. In the Russian market there are fiber-cement panels with a variety of design solutions for their coloring and application of protective coatings. Fiber cement board is a strong and moisture-resistant composite material made from a cement-sand mixture, reinforcing cellulose fibers and special additives. Not being a non-combustible material, the fiber cement boards in accordance with the current mandatory requirements, as a decorative, finishing and facing material for walls and ceilings have restrictions on their use. Existing domestic requirements regarding the methodology for assessing the combustibility of fiber cement products largely narrow the field of using these materials. Therefore, it is advisable to develop the proposals for amending the test methods and the regulatory framework governing their fire-safe extended scope. In the course of this work execution, the main provisions of the regulatory and methodological framework that establish the requirements for the fire-safe use of fiber cement materials are analyzed. Experimental complex studies of fire hazard properties of various types of samples of the fiber cement finishing panels and slabs were carried out. It is established that fiber-cement materials belong to the class of the least fire-hazardous materials. Advisability is determined concerning the introduction to the national regulatory practice of GOST R «Building materials. Test method for fire hazard under thermal exposure with a single burner (SBI)». Classification parameters of the group of non-combustible materials NG2 were established to amend GOST R 57270—2016 (method 1). Classification parameters of the group of non-combustible materials NG2 for making changes in GOST R 57270—2016 (method 1) are established. Proposals were developed to expand the scope of application of the materials and products made of fiber cement as enclosing structures, partitions, and decorative finishes (cladding) in the buildings and structures.

Possibilities of Experimental Determinations of the Modulus of Elasticity in the early Stage of Ageing of Cement Composites

2018 ◽  
Vol 276 ◽  
pp. 35-40
Author(s):  
Romana Halamová ◽  
Dalibor Kocáb ◽  
Barbara Kucharczyková ◽  
Petr Daněk ◽  
Petr Misák
Keyword(s):  
Modulus Of Elasticity ◽  
Early Stage ◽  
Resonance Method ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Load Test ◽  
Cement Composites ◽  
Static Load Test

This paper deals with the possibilities of experimental determination of the dynamic and static modulus of elasticity of fine-grained cement composites in the early stage of setting and hardening - up to 72 hours. Several cement pastes and cement mortars were produced for the purpose of this experiment. The measurement of the modulus of elasticity on the manufactured cement-based composites was carried out in the first 24 hours, each time only by the ultrasonic pulse velocity test using the innovative Vikasonic instrument. In the following 48 hours, the resonance method and the static load test were employed. The results of the pilot measurement and particularly the assessment of the possibilities of determination of the moduli of elasticity are presented in this paper.

Ultrasonic Pulse Method - Influence of Internal Compressive Stress on Results of Testing Calcium Silicate Bricks

2016 ◽  
Vol 722 ◽  
pp. 260-266
Author(s):  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Pulse Method ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Ultimate Compressive Strength ◽  
Technical Literature ◽  
Theoretical Assumptions ◽  
Inner Tension

Measuring with ultrasonic pulse method is influenced by various factors, like loading in particular inner tension when material built in a construction is tested. The paper researches influence of inner tension (load) on testing of calcium silicate bricks with ultrasonic pulse method. Calcium silicate bricks were loaded with force corresponding to 0 % (unloaded test specimens), 10 %, 20 %, 50 %, 60 % of ultimate compressive strength with various content of humidity (dried samples, w=2 %, w=8 % and samples saturated with water). It was found that ultrasonic pulse velocity is not considerably influenced at load of 10% and 20% of ultimate strength of bricks. However, ultrasonic pulse velocity considerably decreases after loading at 50% and 60% of ultimate compressive strength. Most of theoretical assumptions concerning mentioned concrete stated in technical literature were confirmed, however, particular values were different because of differences between concrete and calcium silicate bricks.

scholarly journals Development of Devices for the System of Monitoring the Strength Features of Concrete in Operated Buildings and Structures Based on the Ultrasonic Pulse Method

2019 ◽  
pp. 22-27
Author(s):  
Ya. Serikov
Keyword(s):  
Building Materials ◽  
Pulse Method ◽  
Ultrasonic Pulse ◽  
Technical Condition ◽  
Structural Elements ◽  
Survey Results ◽  
Static And Dynamic Loads ◽  
Object Material ◽  
Negative Factors

  Operation of buildings and structures for various purposes is accompanied by an impact on their structural elements, building materials, and a complex of negative factors. These factors include the lifespan, climatic parameters, static and dynamic loads, dustiness, air pollution, etc. Their action worsens the physico-mechanical characteristics, the structure of concrete. This reduces the reliability of structural elements, reduces the life of the construction object. In DBN V. 1.2-14-2009 «The system of ensuring the reliability and safety of construction objects» set the classification of construction objects by classes of consequences in the event of an accident. The estimated lifetimes of each type of construction objects are also determined. Extension of life is allowed only after inspection and evaluation of the technical condition of the construction object, material characteristics, through the determination of the degree of their compliance with regulatory requirements. The importance of obtaining reliable survey results requires the improvement of relevant instruments and metrology. The described developed system of monitoring of construction objects, as well as instrumentation and system based on the ultrasonic pulse method. They are designed to control the physico-mecha-nical characteristics, the structure of concrete and other building materials. The developed devices and system are characterized by increased accuracy, reliability and reliability of measurements.

scholarly journals Determine the Compressive Strength of Calcium Silicate Bricks by Combined Nondestructive Method

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Jiri Brozovsky
Keyword(s):  
Compressive Strength ◽  
Calcium Silicate ◽  
Pulse Method ◽  
Close Correlation ◽  
Ultrasonic Pulse ◽  
Nondestructive Method ◽  
Production Plant ◽  
Rebound Hammer ◽  
Schmidt Rebound Hammer

The paper deals with the application of combined nondestructive method for assessment of compressive strength of calcium silicate bricks. In this case, it is a combination of the rebound hammer method and ultrasonic pulse method. Calibration relationships for determining compressive strength of calcium silicate bricks obtained from nondestructive parameter testing for the combined method as well as for the L-type Schmidt rebound hammer and ultrasonic pulse method are quoted here. Calibration relationships are known for their close correlation and are applicable in practice. The highest correlation between parameters from nondestructive measurement and predicted compressive strength is obtained using the SonReb combined nondestructive method. Combined nondestructive SonReb method was proved applicable for determination of compressive strength of calcium silicate bricks at checking tests in a production plant and for evaluation of bricks built in existing masonry structures.

REVIEW PAPER ON NON-DESTRUCTIVE TESTING AND THEIR ACCURACIES TO MEASURE THE MECHANICAL PROPERTIES OF CONCRETE

2021 ◽  
Vol 5 (12) ◽  
Author(s):  
Adan Bishar Hussein ◽  
Mohamed Abdi
Keyword(s):  
Building Materials ◽  
Concrete Structures ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Test Methods ◽  
Pulse Velocity ◽  
Destructive Testing ◽  
Capacity Limits ◽  
Destructive Test ◽  
Non Destructive

This paper aims to respond to these concerns through the identification and explanation of the most popular and effective NDT approaches in concrete structures and also their accuracies. The fundamentals of the non-destructive test methods are discussed in terms of their capacity, limits, inspection techniques and interpretations. Factors that affect the performance of NDT an approach are discussed and means of mediate their influence was suggested. Ultrasonic pulse velocity and SONREB methods of Non-destructive test are showed in this paper as past experiments of NDT. NDT of concrete was found to be increasingly recognized as a way of measuring the strength, integrity, resilience and other properties of existing concrete structures, Perceptions of NDT inadequacy are attributed to lack of knowledge of the building materials and the NDT approaches themselves. The goal of this paper is to resolve these issues reviewing some articles already done and defining and discussing the most common popular NDT methods applied to concrete structures.

Влияние направления прозвучивания и собственной частоты преобразователей при испытании динасовых кирпичей ультразвуковым импульсным методом

2021 ◽  
pp. 15-23
Author(s):  
Иржи Брожовский ◽  
Ленка Боднарова
Keyword(s):  
Building Materials ◽  
Pulse Method ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Refractory Materials ◽  
Refractory Bricks ◽  
Silica Refractory ◽  
Measuring Base

Evaluating the quality of refractory materials is one of the important stages of production before these materials are handed over to the customer. One of the required parameters is to evaluate ultrasonic pulse velocity, as determined by measurements performed via the ultrasonic pulse method. Are presents findings on the influence of the direction of transmission and the natural frequency of transducers on ultrasonic pulse method measurements of silica refractory bricks. The findings reveal that the measurement requirements specified in standards for other building materials cannot be fully applied in the case of silica refractory bricks, and the assumption that ultrasonic pulse velocity increases with shorter measuring bases is not confirmed. The highest ultrasonic pulse velocities were measured during transmission across the width of the product, while the lowest velocities were measured over the thickness of the sample. In order to evaluate the quality of silica refractory bricks, it is necessary to unambiguously determine a uniform measuring base for transmission so as to ensure the reproducibility of the measurements performed by different laboratories.

In Situ Determination of the Elastic Modulus of Concrete by Means of Ultrasonic Pulse Method

2018 ◽  
Vol 272 ◽  
pp. 70-75
Author(s):  
Petr Cikrle ◽  
Dalibor Kocáb ◽  
Barbara Kucharczyková ◽  
Ondřej Anton
Keyword(s):  
Elastic Modulus ◽  
Pulse Method ◽  
Ultrasonic Pulse ◽  
In Situ Measurements ◽  
Test Method ◽  
Destructive Test ◽  
Non Destructive ◽  
Thick Layers

The paper deals with the in-situ determination of the modulus of elasticity on the bridge elements using ultrasonic pulse method. This non-destructive test method was chosen for the measurement because of its undisputed advantages that allow the measurement of relatively thick layers of material. For the purpose of the elastic modulus verification the direct measurement was used, in which a pair of transducers (transmitter and receiver) were placed directly opposite to each other. The results of performed in-situ measurements as well as the results of verification tests performed in the laboratory are presented in the paper. The article also discusses the issue of evaluation and interpretation of the results obtained by in-situ measurements using non-destructive test method.

The Partial Discharge Test of Transformer Using Frequency Modulation Type Series Resonance Method

2014 ◽  
Vol 543-547 ◽  
pp. 705-708
Author(s):  
Yang Su ◽  
Qing Hao Wang ◽  
Bo Liu ◽  
Hai Nan Su ◽  
Yan Hai Huang ◽  
...  
Keyword(s):  
Resonance Method ◽  
Test Methods ◽  
Test Device ◽  
Type Series ◽  
Series Resonance ◽  
Resonance Test ◽  
Modulation Type ◽  
Technical Principles ◽  
Frequency Power ◽  
Discharge Test

Traditional frequency power and test equipment cannot meet the requirements. This paper discusses in detail the composition of FM type series resonance test device, technical principles, characteristics and advantages. And also introduces wiring method, test methods, test standard. The instance proves that discharge test of large transformer using the FM series resonance device is convenient and accurate.

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