• Title, Summary, Keyword: Ultrasonic Pulse Velocity Method

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Reliability Improvement of In-Place Concreter Strength Prediction by Ultrasonic Pulse Velocity Method (초음파 속도법에 의한 현장 콘크리트 강도추정의 신뢰성 향상)

  • 원종필;박성기
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.4
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    • pp.97-105
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    • 2001
  • The ultrasonic pulse velocity test has a strong potential to be developed into a very useful and relatively inexpensive in-place test for assuring the quality of concrete placed in structure. The main problem in realizing this potential is that the relationship between compressive strength ad ultrasonic pulse velocity is uncertain and concrete is an inherently variable material. The objective of this study is to improve the reliability of in-place concrete strength predictions by ultrasonic pulse velocity method. Experimental cement content, s/a rate, and curing condition of concrete. Accuracy of the prediction expressed in empirical formula are examined by multiple regression analysis and linear regression analysis and practical equation for estimation the concrete strength are proposed. Multiple regression model uses water-cement ratio cement content s/a rate, and pulse velocity as dependent variables and the compressive strength as an independent variable. Also linear regression model is used to only pulse velocity as dependent variables. Comparing the results of the analysis the proposed equation expressed highest reliability than other previous proposed equations.

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Ultrasonic Nondestructive On-Site Evaluation of Decks in-Service (초음파 비파괴시험법을 이용한 데크재의 현장평가)

  • Oh, Sei-Chang
    • Journal of the Korean Wood Science and Technology
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    • v.43 no.4
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    • pp.486-493
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    • 2015
  • The ultrasonic nondestructive test (NDT) was applied to deck in-service to inspect and evaluate the performance of decking materials using ultrasonic pulse velocity. First, the measuring method between direct and indirect method according to transducer arrangement was studied. Second, the ultrasonic pulse velocity of decks in-service was compared with the passage of time. Finally, the change of ultrasonic pulse velocity was evaluated to expect service life of decking materials. The results of comparison between direct and indirect method was statistically insignificant and the ratio of direct to indirect method was 1.02. 1.05 respectively. The ultrasonic pulse velocity of decks in-service was decreased as the passage of time and the linear relationship in the ultrasonic pulse velocity to passage of time was found. From the results, The ultrasonic NDT will be helpful as an efficient method of on-site management of decks in-service.

Estimating Compressive Strength of High Strength Concrerte by Ultrasonic Pulse Velocity Method (초음파속도법에 의한 고강도 콘크리트의 압축강도 추정에 관한 연구)

  • Lim, Seo-Hyung;Kang, Hyun-Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.3
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    • pp.123-130
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    • 2001
  • The purpose of this study is to suggest the non-destructive equation for the estimation of concrete strength by ultrasonic pulse velocity at the Age of 28day compressive strength of $600{\sim}1000kg/cm^2$. For this purpose, selected test variables were water-hinder ratio, replacement ratio of silica fume, binder content, maximum size of coarse aggregate and sand-aggregate ratio. From the results, the average increase or decrease of ultrasonic pulse velocity is 61m/sec for each 1% of moisture content. And the correlation equation between the ultrasonic pulse velocity and the compressive strength of concrete is as follows. $F_c=896.3V_p-3514$ ($R^2$ = 0.81) where, $F_c$ : compressive strength($kgf/cm^2$), $V_p$ : ultrasonic velocity(km/sec).

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Application on the Prediction Model of the Compressive Strength of Concrete by Maturity Method (적산온도에 의한 콘크리트 압축강도 추정모델의 적용성 검토)

  • Khil, Bae-Su;Kwon, Young-Jin;Nam, Jae-Hyun;Kim, Moo-Han
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.2
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    • pp.177-183
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    • 1999
  • The major object of this study is to investigate experimentally the experimental equation by the non-destructive testing methods of ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number, maturity which are applicable to the evaluation of compressive strength of concrete at early ages. Also test result of mix are statistically analyzed to infer the correlation coefficient between the maturity and the compressive strength of concrete. The results show good application of Logistic curve for estimating strength development under various curing temperature. The relation between ultrasonic pulse velocity, rebound number, combined method of ultrasonic pulse velocity and rebound number and compressive strength of concrete have low correlation coefficient, but maturity method show good correlation coefficient.

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Quantitative Analysis for Termites Damage of Wooden Heritage using Ultrasonic Pulse Velocity (초음파 전파속도법을 이용한 목조 문화유산 흰개미 피해의 정량 평가)

  • Ahn, Jae-Cheol
    • Journal of architectural history
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    • v.24 no.5
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    • pp.41-48
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    • 2015
  • Quantitative analysis of termites damage is important in terms of conservation and maintenance of wooden cultural heritage buildings, because termites makes cavities and decreases the section area of wooden structural members. The purpose of this study is to forecast the range and spread of termites damage in the wooden structural members by using ultrasonic pulse velocity method. Ultrasonic pulse velocity has been used as one of non-destructive test to analysis the internal defect by using difference velocity between medium material and cavity. This method would be effective to analysis termites damages. From the result of the ultrasonic velocity test, the loss rate of area effected by termites damage had a strong correlation with ultrasonic velocity. And it is possible to predict the loss rate of area from by termites damage by using regression equation in the case of structural member of fine tree.

Calculation of Aging Effects of Ultrasonic Pulse Velocity in Concrete by Non-Destructive Test (비파괴시험에 의한 콘크리트 초음파속도의 재령계수 산정)

  • Cho, Chang-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.6
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    • pp.173-179
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    • 2008
  • This paper aims to calculate age coefficient of ultrasonic pulse velocity by non-destructive test. When concrete compressive strength is measured by non-destructive test, rebound test hammer method is applied to estimate age coefficient depending on the course of time after concrete casting, but ultrasonic pulse velocity method is not applied in the process. Although it is necessary to consider age coefficient with change of ultrasonic pulse velocity of concrete depending on aging, there have been little attempts to apply that method. The experiments were conducted to calculate aging effects which will be applied to establish the formula of measuring concrete strength. As a result of experiments, it was found that ultrasonic pulse velocity showed radical changes depending on concrete hardening in comparison with initial standard values. So, it was concluded that age coefficient must be applied to calculate strength. In conclusion, age coefficient of ultrasonic pulse velocity of concrete was suggested on the basis of experimental results.

Crack Depth Evaluation of Concrete Structures using Ultrasonic Pulse Velocity method (초음파 속도법을 이용한 콘크리트 구조물의 균열깊이 측정)

  • 오병환;김광수;김세훈
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.659-662
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    • 1999
  • Ultrasonic pulse velocity method is employed for evaluation of crack depth in concrete structures. Due to the heterogeneous nature of concrete and the indirect transmission arrangement for the transit time measurement through the surface-opening cracks in concrete structures, ultrasonic pulse velocity has so many variations as crack depths and transmission lengths vary. In this study, ultrasonic pulse velocity method is investigated to evaluate the surface-opening crack depth of concrete slabs, reinforced concrete slabs, reinforced concrete flexural members. the resent study gives a modified method for deminishing errors in transit time measurements and show limitations to the evaluation of crack depth in reinforced concrete structures.

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Evaluation Technique of Concrete Strength Using Impact-Resonance and Combined Method (충격공진법 및 복합법을 이용한 콘크리트의 강도 평가 기법)

  • 이광명;이회근;김동수;김지상
    • Journal of the Korea Concrete Institute
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    • v.11 no.4
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    • pp.157-167
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    • 1999
  • Among several non-destructive testing methods, ultrasonic pulse velocity method and rebound index method have been widely used for the evaluation of concrete strength. However, such methods might not provide accurate estimated results since factors influencing the relationship between strength and either ultrasonic pulse velocity or rebound index are not considered. In this paper, the evaluation method of concrete strength using rod-wave velocity measured by impact-resonance method is proposed. A basic equation is obtained by the linear regression of velocity vs, strength data at specific age and then, aging factor is employed in the equation to consider the difference of the increasing rate between wave velocity and strength. Strengths predicted by the proposed equation agree well with test results. Furthermore, the combined method of rod-wave velocity and rebound index is proposed.

A Study on Factors Influencing P-wave Velocity of Concrete (콘크리트의 P파 속도에 영향을 주는 인자에 관한 연구)

  • 이광명;이회근;김동수;김지상
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.725-730
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    • 1998
  • Recently, non-destructive tests are getting popular in evaluating concrete properties without braking specimens. Among several NDT methods, P-wave velocity measurement technique has been widely used to evaluate the stiffness and strength of concrete. The purpose of this study is to investigate factors influencing P-wave velocity measured by impact-resonant method and ultrasonic pulse velocity method, such as moisture content of concrete, existence and size of coarse aggregates, sensor and sampling rate. Test results show that rod-wave velocity measured by impact-resonant method and ultrasonic pulse velocity are significantly affected by the moisture content of concrete, i.e., the lower moisture content, the lower velocity. Moisture content influences rod-wave velocity stronger than ultrasonic pulse velocity. Rod-wave velocity is faster in concrete than in mortar and is also faster in concrete containing small size aggregates. Sensor and sampling rate have little influence on velocity.

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Development of Evaluation Method of External Tendon Force by Using the Deriving Ultrasonic Pulse (유도초음파를 이용한 외부 강선의 긴장력 평가기법 개발)

  • Park, Seung-Bum;Hong, Sung-Su;Yoo, Sung-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.6
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    • pp.181-192
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    • 2007
  • In domestic case, there are no results of corresponding researches for measuring external tendon force. The purpose of the present paper is therefore to measure external tendon force by using deriving ultrasonic method. For this purpose, we designed and manufactured wedges and test system, and measured ultrasonic pulse velocity and pulse amplitude. By using measured data, we tried to analyze the characteristics of tendon force, and to derive the relationship between tendon force and ultrasonic pulse velocity, finally to develop the technic of measuring system using ultrasonic pulse velocity. So tendon force-velocity relationship was proposed by equations, and those equations of which errors were 3.92~8.77% will be possible to adapt in-site.