• Title, Summary, Keyword: Impact -Echo Method

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Experimental Investigation of Impact-Echo Method for Concrete Slab Thickness Measurement

  • Popovics John S.;Cetrangolo Gonzalo P.;Jackson Nicole D.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.6
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    • pp.427-439
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    • 2006
  • Accurate estimates of in place thickness of early age (3 to 28 days after casting) concrete pavements are needed, where a thickness accuracy of ${\pm}6mm$ is desired. The impact-echo method is a standardized non-destructive technique that has been applied for this task. However, the ability of impact-echo to achieve this precision goal is affected by Vp (measured) and ${\beta}$ (assumed) values that are applied in the computation. A deeper understanding of the effects of these parameters on the accuracy of impact-echo should allow the technique to be improved to meet the desired accuracy goal. In this paper, the results of experimental tests carried out on a range of concrete slabs are reported. Impact-echo thickness estimation errors caused by material property gradients and sensor type are identified. Correction factors to the standard analysis method are proposed to correct the identified errors and to increase the accuracy of the standard method. Results show that improved accuracy can be obtained in the field by applying these recommendations with the standard impact-echo method.

Size Estimation of Concrete Structures Using the Impact Echo Method

  • Hong, Seong-Uk;Yoon, Sang-Ki;Lee, Yong-Taeg;Kim, Seung-Hun
    • Architectural research
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    • v.22 no.1
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    • pp.23-31
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    • 2020
  • This study aims to verify a method for accurately estimating the sizes of the column, slab, and beam members of concrete structures using the impact echo method, which is a nondestructive testing method. The concrete specimens are designed and fabricated with six single-layer frame specimens composed of columns, slabs, and beam members based on three strengths of 24, 30, and 40 MPa. To estimate the sizes of the members according to the member types of concrete structures, the experiment was performed using the impact echo method. As a result of estimating the sizes of the concrete column members using the impact echo method, the error rate is 2.9%. As a result of estimating the depth of the concrete beam members, the error rate is 9.7%. And, as a result of estimating the thickness of the concrete slab members, the error rate is 2.4%. These results confirmed that quality control of the members of concrete structures is possible by estimating their sizes using a non-destructive testing method.

Investigation of the Stress-Wave Propagation In Improve the Reliability of the Impact-Echo Method (충격반향기법의 신뢰성 향상을 위한 탄성파 파동전파 특성의 연구)

  • 조미라
    • Journal of the Korea Concrete Institute
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    • v.14 no.2
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    • pp.266-274
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    • 2002
  • The impact-echo test, which is to evaluate the integrity of concrete and masonry structures nondestructively, is an excellent method in the practical application. However, there are cases that the Impact-Echo testing nay result in the low reliability. In this study, the reliability of the Impact-Echo testing was investigated through the numerical simulation of the Impact-Echo testing. The finite element analysis and the analysis based on the dynamic stiffness matrix method was incorporated for the numerical simulation, in which the cases of a sandwiched shear stiffness, an incr+easing or decreasing stiffness, and a homogeneous stiffness. Based on the results of the analysis were considered, this study proposed the approaches to Improve the reliability of the Impact-Echo testing.

Application of Impact Echo Method to Civil Engineering Fields (토목공학 분야에서의 충격반향법의 응용)

  • Jung, Yun-Moon;Ha, Hee-Sang
    • Geophysics and Geophysical Exploration
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    • v.3 no.3
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    • pp.94-100
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    • 2000
  • Many nondestructive test methods used for metallic materials have some limit in application to concrete materials due to their heterogeneity. Impact echo method utilizes the resonance frequency of reflected seismic waves from defects or the boundary between two materials and can be applied to investigate the interior of concrete structures. In this study, a field data acquisition system for the impact echo method was assembled and field tests under various conditions were performed. The impact echo method was applied for investigating thickness/defects/backfilling of concrete structures/tunnel lining/airport pavement. The applicability of the impact echo method to the civil engineering field was substantiated by providing results within $10\%$ errors.

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Applicability of Impact-Echo Method for Assessment of Residual Strength of Fire-Damaged Concrete (화해된 콘크리트의 잔존 강도 평가에 있어서 충격-반향 기법의 적용성)

  • Shin, Sung-Woo;Kim, Seung-Yong;Kim, Jeong-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.5
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    • pp.105-112
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    • 2013
  • In this study, the applicability of impact-echo method for assessment of residual strength of fire-damaged concrete is investigated. A series of standard fire test is performed to obtain fire-damaged concrete specimens. Impact-echo tests are executed on the specimens and the responses are analyzed. Compressive strengths of the fire-damaged concrete are evaluated and correlated with the ultrasonic wave velocities determined from the impact-echo responses. The effectiveness of impact-echo based ultrasonic wave velocity measurement for assessment of residual strength of fire-damaged concrete is discussed.

The Development of Flaw Detection in Concrete by the Impact-Echo Testing Method (충격탄성파법을 이용한 콘크리트 내부의 결함탐상 기술개발)

  • 박선균;임창덕
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.105-110
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    • 1991
  • The conventional high-frequency testing method is difficult to detect flaw in concrete because the high frequency stress wave is strongly attenuated due to the large grain size and heterogeneous structure. For restoration of this problem, we develop the stu요 of flaw detection in large concrete block containing various artificial flaws by low frequency spectrum anlysis of impact-echo waveforms. This impact-echo testing method is possible to determine the flaw size, shape and location in large concrete block even if required some attention in case of containing reinforcing steel bar.

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Estimation of Thickness of Concrete Structures using the Impact Echo Method and Ultrasonic Pulse Velocity Method

  • Hong, Seonguk;Lee, Yongtaeg;Kim, Seunghun;Lee, Changsik
    • Architectural research
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    • v.18 no.4
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    • pp.179-184
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    • 2016
  • The structure must be periodically checked and measures must be taken to prevent deterioration in building construction. From this point of view, a nondestructive test is essential to estimate whether the construction of buildings is proper, and whether the dimension of depositing concrete is consistent and without damage. This study estimated the thickness of the concrete component of construction framework using the ultrasonic velocity method and the impact echo method, in order to investigate reliability of the estimation of the thickness of normal strength concrete and high strength concrete, leading to the following conclusions. In the estimation of the thickness of the concrete structures, specimens of normal strength of 24MPa and specimens of high strength of 40MPa demonstrated an average error rate of 5.1% and 2.2%, respectively. The impact-echo method, one of the non-destructive tests, is verified as an efficient diagnostic technique. With this information, we will determine specific standards for the maintenance of structures, and the re-creation of lost building blueprints.

A Study Using Rebound Method and Impact Echo Method for the Comparison of the Compressive Strength of Concrete Slab (반발 경도법 및 충격반향기법을 이용한 콘크리트 슬래브의 압축강도 비교에 관한 연구)

  • Hong, Seong-Uk;Cho, Young-Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.3
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    • pp.199-207
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    • 2008
  • As infrastructures are being deteriorated, nondestructive evaluation of existing structures and construction quality control are increasingly demanded. The importance of predicting compressive strength of concrete structure is also gradually increasing in construction industry. The estimation of concrete compressive strength is a critical factor of the construction management and quality control. This study has been conducted using Schmidt hammer test and Impact echo method, which are nondestructive test methods for the comparison of the concrete compressive strength. It is focusing to examine the relationship between compressive strength of concrete and rebound number by Schmidt hammer test result by Impact echo method. It was found that concrete compressive strength and rebound number have a close correlation.

Characteristics of Elastic Wave in Fire damaged High Strength Concrete using Impact-echo Method (충격반향기법을 이용한 화해를 입은 고강도 콘크리트의 탄성파 특성)

  • Lee, Jun Cheol;Lee, Chang Joon;Kim, Wha Jung;Lee, Ji Hee
    • Fire Science and Engineering
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    • v.29 no.1
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    • pp.1-6
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    • 2015
  • In this study, the damages of high strength concrete exposed to high temperature have been evaluated by the impact echo method. Elastic wave velocity and dynamic modulus of elasticity were measured by the impact echo method, and the compressive strength and the static modulus of elasticity were measured by the compression testing method after exposure to high temperature. The results showed that elastic wave velocity has a linear correlation with the compressive strength and dynamic modulus of elasticity has a linear correlation with static modulus of elasticity. Based on results, it is concluded that the impact echo method can be effectively applied to evaluate the mechanical properties of fire damaged high strength concrete.

A Study of Structural Safety Diagnosis using Frequency Domain Analysis of Impact-Echo Method (충격반향기법의 주파수영역 해석을 이용한 구조물 안전진단에 관한 연구)

  • 안제훈;서백수
    • Tunnel and Underground Space
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    • v.14 no.1
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    • pp.35-42
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    • 2004
  • Impact-echo is a method for non-destructive testing of concrete structure. This method is based on the use of impact-generated stress wave which is propagated and reflected from internal flaws within concrete structure and external surface. In this study, we performed non-destructive testing using impact-echo methods for safety diagnosis of civil engineering and building structures. There are testing cases for the three models having one-dimensional form ; The first case is the measurement of thickness change of the model, the second is the detection of cavity in the model, and the third is the predictions of the lining thickness and the position of the cavity under tunnel lining condition.