Non-Destructive Testing of Technical Conditions of RC Industrial Tall Chimneys Subjected to High Temperature

The accepted methods for testing concrete are not favorable for determining its heterogeneity. The interpretation of the compressive strength result as a product of destructive force and cross-section area is burdened with significant understatements. It is assumed erroneously that this is the lowest value of strength at the height of the tested sample. The top layer of concrete floors often crumble, and the strength tested using sclerometric methods does not confirm the concrete class determined using control samples. That is why it is important to test the distribution of compressive strength in a cross-section of concrete industrial floors with special attention to surface top layers. In this study, we present strength tests of borehole material taken from industrial floors using the ultrasonic method with exponential spot heads with a contact surface area of 0.8 mm2 and a frequency of 40 kHz. The presented research project anticipated the determination of strength for samples in various cross-sections at the height of elements and destructive strength in the strength testing machine. It was confirmed that for standard and big borehole samples, it is not possible to test the strength of concrete in the top layer of the floor by destructive methods. This can be done using the ultrasonic method. After the analysis, certain types of distributions of strength across concrete floor thickness were chosen from the completed research program. The gradient and anti-gradient of strength were proposed as the new parameters for the evaluation of floor concrete quality.

“…The borehole materials were taken from an industrial floor 15 cm thick. Calculation of compressive strength from ultrasound wave velocities was done with the use of Equation (4).…”

Section: Concrete Strength Is Changing Across Entire Section With a Qmentioning

confidence: 99%

“…Tests of this material concern both spatial structure (porosity, tightness, pore, and grain distribution) and its basic parameter, that is, compressive strength. Modifications of this composite aim at the improvement of its homogeneity [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Tests of Concrete Strength across the Thickness of Industrial Floor Using the Ultrasonic Method with Exponential Spot Heads

Stawiski

Kania

2020

“…As mentioned in [28], the nondestructive testing of reinforced concrete chimneys, especially the high ones is an important element in the assessment of their condition, making it possible to forecast their safe service lifespan. Industrial chimneys are often exposed to the strong action of acidic substances—they are adversely affected by the flue gas condensate on the inside and by acid precipitation on the outside.…”

Section: Description Of the Articles Presented In The Issuementioning

confidence: 99%

Non-Destructive Testing of Materials in Civil Engineering

Schabowicz

2019

This issue was proposed and organized as a means to present recent developments in the field of non-destructive testing of materials in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of non-destructive testing of different materials in civil engineering, from building materials to building structures. The current trend in the development of non-destructive testing of materials in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained.

“…These fibers melt during the exposure to fire allowing the release of the steam pressure, thus reducing the risk of concrete spalling [ 6 ]. Nondestructive tests (NDT) methods based on acoustic, electromagnetic, thermographic, and optical phenomena are becoming more popular for determining several structural properties and behavior of reinforced concrete (RC) elements [ 7 , 8 , 9 ]. For example, thermographic testing can monitor the temperatures which can influence the reinforcement corrosion in concrete [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

“…Nondestructive tests (NDT) methods based on acoustic, electromagnetic, thermographic, and optical phenomena are becoming more popular for determining several structural properties and behavior of reinforced concrete (RC) elements [ 7 , 8 , 9 ]. For example, thermographic testing can monitor the temperatures which can influence the reinforcement corrosion in concrete [ 8 ]. Electromagnetic NDT can be used to detect location and diameter of reinforcement bars in RC elements and fiber spacing in steel fiber-reinforced concrete elements [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Acoustic Emission Monitoring of High-Strength Concrete Columns Subjected to Compressive Axial Loading

Eid

Muravin²,

Kovler

2020

Acoustic Emission (AE) nondestructive tests have attracted great interest for their use in the determination of structural properties and behavior of reinforced concrete (RC) elements. One of the applications this method can contribute to is in high-strength concrete (HSC) columns. These elements have a great advantage in the lower stories of high-rise buildings. However, the premature failure of the concrete cover and the brittleness nature of the failure is of a concern for engineers. This paper presents a study on the AE monitoring of HSC columns subjected to compressive axial loading. The study consists of four large-scale reinforced HSC columns with different confinement reinforcement and height. It is shown that the AE distributions in the columns are categorized by three stages. Moreover, the levels of loads reached at the first AE macro event are similar to the lower range levels of the nominal axial compressive strengths of the tested specimens, while the majority of macro AE events are located at the concrete cover. Based on the results of this study, AE monitoring can provide indications for the damage and load levels attained by reinforced high-strength concrete columns subjected to compressive axial loading.