• 콘크리트학회논문집
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• 제19권1호
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• pp.75-81
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• 2007

콘크리트는 전체 체적의 $70{\sim}80%$가 골재로 이루어져 있다. 따라서 골재의 품질은 콘크리트 특성에 지대한 영향을 미친다. 현재 건설 현장에서는 부순모래 콘크리트의 비파괴 강도 추정을 일반적으로 슈미트해머를 이용한 반발 경도법이나 초음파를 이용한 초음파속도법 그리고 둘을 조합한 복합법을 이용하고 있으며 기존의 천연골재를 사용한 콘크리트에 의해 얻어진 여러 가지 제안식들에 적용시켜 추정하고 있다. 따라서 본 연구의 목적은 전형적인 파괴 시험과 코어 채취 그리고 반발경도법과 초음파속도법을 이용하여 부순모래 콘크리트의 강도 추정식을 제안하고자 하였다. 실험의 변수는 양생 재령과 양생 조건 그리고 콘크리트의 설계기준강도이다. 그 결과 본 연구에서 얻은 제안식이 기존식에 비해 모든 측면에서 양호한 것으로 나타나 실제 건설 현장의 부순모래 콘크리트 구조물의 평가 기술 향상에 기여할 것으로 사려 된다.

• 농업과학연구
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• 제39권1호
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• pp.111-116
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• 2012

Nondestructive evaluation of seed viability is one of the highly demanding technologies for seed production industry. Conventional seed sorting technologies, such as tetrazolium and standard germination test are destructive, time consuming, and labor intensive methods. Near infrared spectroscopy technique has shown good potential for nondestructive quality measurements for food and agricultural products. In this study, FT-NIR spectroscopy was used to classify normal and artificially aged lettuce seeds. The spectra with the range of 1100~2500 nm were scanned for lettuce seeds and analyzed using the principal component analysis(PCA) method. To classify viable seeds from nonviable seeds, a calibration modeling set was developed with a partial least square(PLS) method. The calibration model developed from PLS resulted in 98% classification accuracy with the Savitzky-Golay $1^{st}$ derivative preprocessing method. The prediction accuracy for the test data set was 93% with the MSC(Multiplicative Scatter Correction) preprocessing method. The results show that FT-NIR has good potential for discriminating non-viable lettuce seeds from viable ones.

• 한국농공학회논문집
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• 제46권1호
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• pp.61-71
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• 2004

The performance evaluation and deflection of 3 spans concrete simplicity slab bridge analyzed by non-destructive and loading test. Compressive strength of slab and pier appeared in the range of each 353∼366 kgf/$cm^2$ and 152∼215 kgf/$cm^2$ in rebound number test. Also, it appeared that concrete quality of slab was good after performance improvement. The average compressive strength of slab by core picking appeared 229 kg/$cm^2$. In reinforcing bar arrangement test of span and member, it appeared that horizontal and vertical reinforcing bar was arranged to fixed interval. The value of calculation deflection that carried structural analysis with deflection analysis wave in static loading test appeared higher than that of experimental deflection and it appeared that hardness of this bridge was good. Maximum impact factor that estimated from deflection by running speed in dynamic loading test appeared by 0.216 in 10 km/hr running speed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.69-70
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• 2013

This is an foundational study to adequacy the non-destruction testing for the estimation of compressive strength of high strength concrete The results are as follows, In high strength concrete, H type is NR type rebound number rather than higher. The relation between rebound number and compressive strength of high strength concrete have lower coefficient. when compressive strength estimation of high strength concrete, it consider that rebound hardness test is not applied and should be consider to combined method or addition method.

• 한국정밀공학회지
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• 제18권9호
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• pp.37-44
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• 2001

Ultrasonic testing has a characteristics such as excellent permeability, high-sensitivity to find defect and an almost exact measurement for position. size and direction of inner defect, which differ from other non-destructive testing. In the study, we developed program into optimal testing condition, to distinguish obstacle echo and defect position. This program shows generation and processing of ultrasonic pulse. We compared simulation with ultrasonic test in 45$^\circ$, 60$^\circ$and 70$^\circ$transducer. Test results were in accordance with simulation within 0.1~7.2%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.13-16
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• 2005

This study is aimed to investigate the strength variation of fire-damaged reinforced concrete column by non-destructive test. It is studied to infer the recovery degree of residual strength of fire-damaged concrete. For measuring the surface hardness of RC columns. Schmidt hammer test is used. Testing is performed three-times: before fire test, directly after fire test and after 20 days.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.622-628
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• 2004

In general, Reinforced Slopes by Shotcrete are difficult to inspect because of stiff Slope and highly Working Area. So the Inspection Techniques are needed by the Non-contact and Non-destructive. On this Study, Appling the safety method to finding the weak zones(cavity area, dampness area, etc.) by using the Infrared Thermal Technique That is detecting the Detail Thermal Difference on the Surface of Reinforced Slopes by Shotcrete.

• 한국건축시공학회지
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• 제16권3호
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• pp.229-235
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• 2016

현장에서는 콘크리트 공사시 거푸집 탈형작업을 위한 다양한 기술들이 활용되고 있다. 그중에서 콘크리트의 압축강도추정을 위한 비파괴 시험방법에는 다양한 방법들이 제시되고 있지만, 일반적으로 타격법(반발경도법이라 칭함)과 비타격법(초음파법이라 칭함)을 활용한 시험방법이 주로 활용된다. 비파괴시험에 의한 압축강도의 추정은 경험 값에 의한 방정식에 의하여 계산할 수 있으며 다양한 식들이 제시되고 있으나, 초기재령에서 조기강도가 발현되는 콘크리트에 대한 데이터는 적은 편으로 기존의 강도추정식에 의한 압축강도의 계산에는 한계점이 있을 수 있다. 본 연구에서는 현장에서 주로 활용되는 조기탈형용 콘크리트의 배합을 활용하여 소형 공시체 및 Mock-up 시험체의 파괴 및 비파괴검사를 수행하였으며, 기존 비파괴검사 추정식을 통한 강도 결과 값을 분석하였다. 실험결과, 기존 연구의 비파괴시험에 의한 제안식을 활용한 압축강도 추정값은 파괴시험방법에 비하여 하회하는 경향으로 70% 이하의 값을 나타냈으며, 초음파속도에 의한 신뢰성은 강도가 높아질수록 낮아지는 것으로 확인되었다. 본 연구의 범위에서 조기강도 발현 콘크리트의 강도추정에 있어 기존식의 활용의 한계점이 있을 것으로 분석되어, 24~60MPa의 콘크리트를 대상으로 반발경도법 및 초음파속도법에 의한 추정식을 제안하였다.

• Journal of Welding and Joining
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• 제33권4호
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• pp.57-62
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• 2015

Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing(ECT) is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. The New ECT sensor which can detect inner defects was developed regardless the condition of surface. This sensor is verified to do experiment which measure the loss of induced electromotive force. The loss of induced electromotive force was measured in 5.4% and this low frequency ECT device can detect internal defects at depth 20 mm.

• Journal of Welding and Joining
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• 제33권4호
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• pp.63-67
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• 2015

Non-destructive techniques are used widely in the metal industry in order to control the quality of materials. Eddy current testing(ECT) is one of the most extensively used non-destructive techniques for inspecting electrically conductive materials at very high speeds that does not require any contact between the test piece and the sensor. The New ECT sensor which can detect inner defects was developed regardless the condition of surface. This sensor is verified to do experiment which measure the loss of induced electromotive force. The loss of induced electromotive force was measured in 5.4% and this low frequency ECT device can detect internal defects at depth 20 mm.