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Assessing Concrete Strength: Insights from Schmidt Rebound Hammer and Ultrasonic Pulse Velocity Techniques

Fodil Narmane, Chemrouk Mohamed

Inżynieria Mineralna

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2025

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Vol. 2, no. 2

art. no. 51

EN

Concrete strength assessment is pivotal in ensuring the structural integrity and longevity of various constructions. Nondestructive testing (NDT) methods have emerged as indispensable tools for predicting concrete strength in situ, facilitating timely interventions and quality assurance protocols. Among these methods, the Schmidt rebound hammer (RH) and ultrasonic pulse velocity (UPV) techniques have gained prominence due to their simplicity, cost-effectiveness, and on-site applicability. This study delves into the relevance and efficacy of RH and UPV techniques for predicting concrete strength, focusing on the development of mathematical correlation models between NDT parameters and compressive strength. The research involves conducting comprehensive experimental investigations on a diverse range of concrete specimens encompassing different mix designs, strength ranges, and ages. Compressive strength, the gold standard for concrete strength determination, was evaluated through destructive testing methods. Concurrently, non-destructive assessments employing RH and UPV were performed on the same specimens. The rebound values from Schmidt Rebound Hammer test and the velocity of ultrasonic pulses were correlated with compressive strengths to establish predictive models. Uni-parametric (RH-Strength and UPVStrength) correlation models, as well as combined models, were developed to explore the relationship between NDT parameters and concrete compressive strength. In evaluating concrete strength using the Schmidt rebound hammer test, it was observed that this surface test exhibited less sensitivity to variations in concrete mix design within the same strength range. Instead, its sensitivity primarily stemmed from variations in concrete strength, attributed partly to the density of the cement paste at the surface. Conversely, the Ultrasonic Pulse Velocity test emerged as more relevant for assessing concrete strength, given its ability to investigate concrete depth. However, it displayed lower sensitivity to variations in concrete mix design when dealing with high-strength concretes. Despite these nuances, the proposed correlation models demonstrated reliability and accuracy, evident from the coefficients of correlation obtained. Furthermore, the utilization of combined models facilitated an improvement in prediction accuracy compared to uni-parametric models alone. Notably, it was observed that concrete mix design and the age of concrete exerted significant influence as factors diminishing the precision of concrete strength prediction using non-destructive testing (NDT) methods. These findings underscore the importance of considering such influencing factors and refining model calibration processes to further improve the reliability of NDT-based concrete strength assessments. RH and UPV techniques offer valuable insights into concrete strength prediction, aiding rapid on-site assessments and quality control during construction projects. While both methods present strengths and limitations, integrating them alongside conventional testing approaches enhances the reliability and efficiency of concrete strength evaluation. The development of correlation models facilitates quantitative predictions of concrete strength based on NDT parameters, advancing the state-ofthe-art in non-destructive evaluation of concrete. Further research focusing on refining testing protocols and calibration techniques is warranted to optimize the accuracy and applicability of these techniques in concrete engineering practices.

2

Stanowisko do badań nieniszczących z zastosowaniem aktywnej termografii w podczerwieni

Sochacka Olga

Przegląd Elektrotechniczny

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2021

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R. 97, nr 1

174--177

PL

Zaprezentowano stanowisko do badań nieniszczących z zastosowaniem aktywnej termografii w podczerwieni. Stanowisko składa się z kamery termowizyjnej, lamp halogenowych, komputera stacjonarnego z oprogramowaniem IrNDT, karty akwizycji danych DAQ, oraz modułu sprzętowego AT IRXBOX służącego do sprzętowego wyzwalania rejestracji termografów i źródła wymuszenie cieplnego.

EN

In article has been presented the stand for non - destructive research using infrared thermography. A stand consists of a thermal imaging camera, halogen lamps, desktop with IrNDT software, DAQ data acquisition card and AT IRXBOX hardware module used for recording of thermographs and sources of heat - induction.

3

Direct and In-Direct Strength Evaluation of Refractory Structural Elements Subjected to Temperature Cycles

Awchat Ganesh D.

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no. 4

160--173

EN

Refractory structural elements used in the lining work of refractory are exposed to a more complex stress-strain behavior due to the temperature variation cycle. To investigate the performance of refractory structural elements, an attempt was made in this research to cast Aluminium Oxide, i.e., 80% Al2O3 castable in the form of cubes of 150 mm x 150 mm x 150 mm size and heated to different temperatures of 100°C to 800°C. Rebound Hammer Test, Ultrasonic Pulse Velocity (UPV) test performed to evaluate compressive strength refractory structural elements qualitatively and quantitatively. Direct compressive strength of identical heated cube specimens investigated using a compression testing machine. The relationship between direct and indirect test results of compressive strength was established and compared. Four different grade bricks B-1, B-2, B-3, and B-4 heated to 800°C to study the formation of microcracks at high temperatures. The bricks were fired for 0, 2, 4, 6, 8, and 10 cycles up to 800°C and same used for UPV testing, Modulus of Rupture (MoR) tests. The study aimed to correlate direct and indirect strength results helpful in selecting suitable refractory materials in practice. UPV test values plotted with cube specimen heated at 100°C to 800°C revealed that UPV values decrease as temperature increases. The compressive strength of cubes increased with temperature due to the evaporation of water vapor in the matrix and the ceramic bonding effect, which increased cube compressive strength after heating. The graph of the relationship between MoR and UPV for all grade bricks at five heating cycles up to 800°C revealed thermal cracks observed in all B-2 bricks only after third loading cycles. For other specimens, the proportionality relationship between them is linear. The experimental outcome of research provides technical support for the selection of structural elements material in refractory.

4

Wykrywanie defektów w skórach naturalnych z użyciem liniowego promiennika ciepła

Chudzik S.

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

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2017

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Nr 54

17--20

PL

W artykule przedstawiono wyniki badań nieniszczących nad opracowywaną metodą wykrywania defektów naruszających jednorodną strukturą budowy wewnętrznej i zewnętrznej wygarbowanych skór naturalnych, zwłaszcza licowych. W prezentowanej metodzie użyto liniowego promiennika podczerwieni do osiągnicia wymuszenia temperatury o charakterze impulsowym. Do pomiaru rozkładu temperatury na powierzchni badanej, w eksperymencie użyto kamery termowizyjnej. W badaniach zaproponowano opracowany algorytm przetwarzający pakiet termogramów zarejestrowanych w czasie ochładzania powierzchni badanej skóry. Przedstawiono wybrane wyniki badań eksperymentalnych oraz wyniki działania opracowywanego algorytmu wykrywania defektów w skórach. Osiągnięto zadowalające wyniki badań.

EN

The paper deals with a method of detecting defects of uniform internal and external structure of tanned natural leather, especially grain leather. These defects can result from damages of the leather originated during an animal lifetime or later during the tanning and finishing process. In the presented method a linear infrared lamp was used to obtain the impulse heat input. The temperature response on the examined leather surface was measured using an infrared camera. The series of thermograms recorded during the leather cooling were processed using the developed algorithm. Selected r esults of experiments illustrating the performance of the processing algorithm are presented in the paper. The results obtained in the tests were satisfactory. Computations were carried out in the Matlab software environment. The presented solution is a part of a project whose goal is to design an industry device for non destructive testing and detecting structure defects in natural leather used in the furniture upholstery.

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Zastosowanie termografii aktywnej w badaniu stanu powierzchni elementów stalowych

Jurek M.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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z. 64, nr 4/II

65--75

PL

Powszechność w budownictwie stali, jako materiału konstrukcyjnego, przy jej jednoczesnej podatności na korozję wymusza opracowywanie i stosowanie metod oraz procedur diagnostycznych, pozwalających na możliwie jak najwcześniejsze wykrycie i zlokalizowanie ognisk korozji. Obok szeregu dobrze znanych i skutecznych na tym polu badań metod nieniszczących (ang. Non Destructive Testing, NDT), jak badania ultradźwiękowe, rentgenografia, badania penetracyjne, czy też ocena wizualna, co raz większe uznanie zyskuje termografia aktywna. W pracy przedstawiono wyniki badań laboratoryjnych, których celem było określenie skuteczności metody termografii aktywnej w detekcji i lokalizacji korozji i innych wad powierzchni elementów stalowych. Przeprowadzono pomiary na próbkach laboratoryjnych w postaci blachy stalowej, o powierzchni zarówno nie malowanej, jak i pokrytej zróżnicowanymi powłokami. Przeanalizowano szereg zaburzenia w postaci korozji, otworu wypełnionego masą szpachlową, wżerów, zabrudzenia klejem epoksydowym. Pomiary wykonano z wykorzystaniem wymuszenia w postaci lampy halogenowej oraz głowicy generującej prądy wirowe. Przeanalizowano zróżnicowane czasy wymuszenia i rejestracji odpowiedzi analizowanych próbek laboratoryjnych. Zarejestrowane sekwencje termogramów podlegały przetwarzaniu poprzez wyznaczenie funkcji aproksymujących o zróżnicowanych parametrach. Uzyskane wyniki przedstawiono w postaci map wartości, określonych współczynników funkcji aproksymujących.

EN

The commonality of steel as a structural material, with its simultaneous corrosion susceptibility, require the development and application of diagnostic methods and procedures to detect and locate corrosion at the earliest stage. Apart from a number of well known and effective nondestructive testing (NDT) such as ultrasound, penetration method or visual assessment, active thermography is becoming increasingly popular. The paper presents the results of laboratory tests aimed at determining the effectiveness of the active thermography method in the detection and localization of corrosion and other defects in the surface of steel elements. Measurements were made on laboratory specimens in the form of sheet steel, both unpainted and covered with varied coatings. A number of defects in form of corrosion, holes filled, pitting, dirt with epoxy adhesive were analyzed. The measurements were made using the halogen lamp and the eddy currents generator. Varies times of excitation and measurements were analyzed. Recorded sequences of thermograms were processed by assigning approximation functions with different parameters. The obtained results are presented in the form of maps of values, certain approximation coefficients.

6

The Influence of Sensitivity Field of Dual Transducer Probes on Accuracy of Discontinuity Sizing and Evaluation in Terms of Testing of Forgings According to EN 10228-3

Kaczmarek R., Kaczmarek K.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 3

1677--1682

EN

The article presents results of research on the impact of sensitivity distribution of double transducer probes, which are often used in non-destructive ultrasonic testing of components such as forgings. Distribution of sensitivity measured in two orientations, parallel and perpendicular to the plane of separation of a double transducer probe has been tested and analyzed. A significant influence of orientation of a probe on echo envelope of an artificial point discontinuity has been studied. It has revealed great differences in length and shape of an echo envelope, depending on a type of probe and orientation of a probe separation plane to the moving direction. Eventually, the analysis of practical consequences of dual transducer probes usage for characterization of a type, dimensioning and evaluation of internal discontinuities, in accordance to the methodology specified in EN 10228, has been conducted.

7

Computed Tomography for the Eyaluation of the Influence of Porosity on Stress Distribution

Powązka D., Brune M., Eichlseder W., Leitner H., Oppermann H.

Archives of Foundry Engineering

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2008

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Vol. 8, iss. 1 spec.

291--294

EN

High pressure die casting of aluminium components leads to the formation of pores, which decrease the fatigue life under cyclic loading. The fatigue life depends on the location, size, form and general volume of porosity. The porosity in die cast aluminium components is not distributed homogeneously and is concentrated in the interior of the component. Furthermore usually a small layer close to the surface is free of porosity. For the evaluation of fatigue life, it is necessary to characterise the porosity precisely. Traditional metallographic investigation methods do not adequantly identify the pores and mostly destroy the material. Modern analysis method, like computed tomography provide the capability of precise identification of porosity. In order to identify the geometry of a pore, a small specimen must be scanned. The result is a three dimensional model of the porc-afflicted material. Subsequently this model can be meshed to a fine degree. In this way a real strain distribution, caused by non-spherical pores, can be calculated using CAE software. Results published in the literature describe precisely two-dimensional and simplified three-dimensional structures. This article illustrates 3D computed tomography investigations of the porosity of cast aluminium components. The results provide an important input for the evaluation of reliable fatigue life calculation methods.

PL

Podczas ciśnieniowego odlewania komponentów aluminiowych powstają pory, które zmniejszają wytrzymałość zmęczeniową materiału. Redukcja wytrzymałości zależy od położenia, rozmiaru oraz kształtu por, które w podzespołach aluminiowych nie są rozłożone jednorodnie, lecz skoncentrowane są w środkowych partiach odlewów, co znacznie utrudnia oszacowanie ich rzeczywistego oddziaływania. Poza tym komponenty aluminiowe zawierają wąski obszar przypowierzchniowy, który jest wolny od por. Tradycyjne metalograficzne metody badań nie identyfikują w pełni porowatości i zwykle niszczą materiał. Nowoczesne metody analizy, takie jak tomografia komputerowa dają możliwość precyzyjnego opisu kształtu błędów, który jest konieczny do dokładnego określenia jego wpływu na wytrzymałość zmęczeniową. Zdefiniowane tą techniką pojedyncze błędy o rzeczywistym kształcie dzielone są na elementy skończone. W ten sposób oblicza się realny, niejednorodny rozkład naprężeń, spowodowany niekulistymi porami o różnych rozmiarach, położonymi w różnej odległości od powierzchni. Wyniki publikowane w literaturze opisują dokładnie dwuwymiarowe oraz uproszczone trójwymiarowe struktury. Niniejsza publikacja przedstawia szczegółowe trójwymiarowe analizy, które stanowią istotny wkład do poprawienia jakości metod prognozowania wytrzymałości zmęczeniowej konkretnych podzespołów aluminiowych.