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Microprocessor application to concrete crack depth measurement
Fifth Pan Pacific Conference on Nondestructive Testing, Vancouver (Canada), Apr. 1987, pp. 269-277. Atomic Energy of Canada Limited, AECL-9394 (Mar. 1987) The accuracy of magnetic induction testing for reinforced steel has been the subject of previous research. This paper describes the trial manufacture of various types of probe coils and the investigation of reinforcing steels in concrete with various test frequencies. As a result, it was found that the size of the signals was influenced by various factors such as depth (the distance between probe coil and reinforcing steel), and diameter of reinforcing steels diameter, the signal magnitude was influenced by the covering depth. When this depth was constant, it was obvious that similar quality steels with different diameters had an effect on the phase angle and the signal magnitude. 40292
Hara, Tadakatu, lshii, Yugoro; Yoshikawa, Satoshi.
Distribution of pulse velocity and sound pressure in mortar and concrete by ultrasonic test Fifth Pan Pacific Conference on Nondestructive Testing, Vancouver (Canada), Apr. 1987, pp. 220-228. Atomic Energy of Canada Limited. AECL-9394 (Mar. 1987) Investigations of concrete structures showing some distress has been performed to prevent further deterioration. A laboratory investigation of the application of ultrasonic pulse velocity in concrete has been conducted. The authors used a longitudinal wave probe at various frequencies, and found that the frequency has no significant effect in the propagation of pulse velocity in the concrete. Ultrasonic testing in concrete structures has been found to be more convenient when consideing the distribution of the pulse wave, which can define radial propagation direction in the transducer. 40277 Delebarre, C.; Rouvaen, J.M.; Frohly, J.; Bruneel, C. Digital signal processing methods for ultrasonic baekscattered waves in
highly heterogeneous media Proceedings of the I E E E 1987 Ultrasonic Symposium, Denver, Colorado (United States), 14-16 Oct. 1987. Vol. 2, pp. 1053-1056. Edited by B.R. McAvoy. Institute of Electrical and Electronics Engineers. This paper compares two numerical signal processing method which give a signature of highly heterogeneous media based upon the evaluation of mean spacing between the heterogeneities randomly distributed in the medium. The first method is related to the autocorrelation function for the echoes. However, this function doesn't reflect the medium characteristics in the case of highly heterogeneous media: the impulse response of the whole measurement set biases the obtained signature. The second one is derived from the power spectrum of the radio frequency (RF) backscattered signal and gives a non biased signature for red signal and gives a non biased signature for highly heterogeneous media. Data are presented for highly heterogeneous media like concrete. 40165
Goebbels, K.; Dobmann, G.
Localization of steel-reinforcements in concrete: determination of their diameter and cover-thickness measurement by magnetic stray flux Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7A, pp. 533-540. Edited by D . D . T h o m p s o n and D.E.Chimenti, Plenum Press, 1988. An insufficient cover-thickness of concrete is the main reason for corrosion of steel-reinforcements in civil engineering. The volume enlargement of the corroded steel produces stresses at the concrete matrix, initiating cracks, crack growing and finally cover destruction. Codes therefore demand a certain cover-thickness y¢ as function of the steel reinforcement diameter d and the environmental corrosion conditions. A new method is presented to measure the relevant parameters Yc,d non-destructively, based on classical Maxwell- theory: a magnetic field produced by a DC-electromagnetic yoke magnetizes the reinforcement resulting in a stray field. This is measured by an array of Hall-probes situated between the pole shoes. The evaluation leads to the position and diameter of the reinforcement as well as to the cover thickness. The results show that the method meets the practical requirements. 39964 Askegaard, V.; Moiler, P.H. Ultimate load of plain concrete specimens determined nondestruetively N D T International, Vol. 21, No. 6, pp. 427-429 (Dec. 1988) Acceptance of plain concrete specimens, such as large sewers, depends on results of rupture tests carried out on test samples. As such specimens are costly, acoustic emission (AE) has been investigated as a possible method of determining rupture load without unacceptably damaging the specimens, which can then be reused. The AE technique provides an acceptance-rejection criterion and can be used to study the development of strength in newly cast specimens.
Mahadeva lyer, Y.; Srividyara]agopalan, C.; Nayak, N. U.; Suresh Babu, R.H. 39930
Metal depth detec~r Bulletin of Electrochem., Vol. 3, No. 3, pp. 279-280 (May-Jun. 1987) Metal detectors based on eddy current principles find varied applications. They are used in the detection of metals underground, for security purposes, the measurement of cover thickness in reinforced concrete (RCC) structures, etc. This paper describes the design and performance details of such a metal detector used in the measurement of cover thickness of reinforcements in RCC structures.
112
39903
Kozlov, V.N.; Shevaldykin, V.G.; Yakovlev, N.N.
Experimental determination of the attenuation of an ultrasonic wave in concrete Soviet Journal of Nondestructive Testing, Vol. 24, No. 2. pp. 132-140 (Feb. 1988) The basic technical difficulties occurring in experimental determination of the attenuation coefficient of longitudinal ultrasonic vibrations in concrete are analyzed and possible means of overcoming them are shown. Measurements of results for attenuation coefficients at frequencies of 50-300 kHz in concretes. differing in material and panicle size of the coarse filler, are given. 39895
Roy, S.K.; Murthy, C.K.; Krishnamurthy, N.
Statistical study of principal parameters for pulse velocity and compressive strength of concrete Materials Science Forum, Vols. 34-36, No. 2, pp. 1077-1085 (1988). Proceedings of the International Ceramic Conference A U S T C E R A M ' 8 8 Sydney, Australia, 21-26 Aug. 1988. C.C. Sorrell, B. Ben-Nissan (Eds.) This paper is concerned with the statistical analysis of the four dominant parameters affecting concrete strength as related to the pulse velocity, namely: water content, cement content, ageing and cement type. Two types of cement and two levels (low and high) of the other three parameters were investigated by means of 24 factorial experiment. The measured responses for pulse velocity and compressive strength were analysed for statistical significance. 39654
Bussiere, J.F.; Lord, M.; Non, M.
Relation between hardness, microstructure and magnetic coercive force in rail steels Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sop. 1987. Vot. 3, pp. 1863-1869. Pergamon Press, 3173 pp. (1988) Measurements of magnetic coercive force of fully peariitic rail steels having different hardnesses, chemical composition and thermal history are presented between -200 and 6000?C. A pronounced peak in coercive force is generally observed at the Curie temperature of the cementite (FejC) phase, approx 2100?C for.plain carbon rails. This peak shifts rapidly to lower temperatures with small additions of chromium and with heat-treatment, resulting in large changes of I-|c at room temperature, which are unrelated to changes in mechanical properties. Above the Curie temperature of the carbide phase, the coercive force is found to correlate well with hardness regardless of chemical composition and heat-treatment, inferring that in this temperature range both are controlled by the same microstructural parameters, whereas below approx 2100?C the detailed magnetic behavior of the carbide phase has a strong influence on Hsub/c/. 39651
Joyce, R.P.; Koller, G.M.
Rapid non-destructive delamination detection Proceedings of the 16th Symposium on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 349-361. Nondestructive Testing Information Analysis Center, Texas, USA. Delaminations in concrete bridge decks are a major cause of bridge maintenance problems. While the current sonic methods of testing arc reliable, they are too slow for the survey application. A rapid, non- destructive method for assessing the general condition of the bridge decks without closing the deck to traffic is needed. Electromagnetic sounding, by using pulsed radar, was used in the development of a rapid survey system. This inspection technique can inspect through asphaltic overlays. Creditable surface cover of sand/pebbles, lane marking paint, oil spots and damp pavement have negligible effects on the inspection data. Digital image processing techniques are used to present the individual range scans in a modified B-scan format, providing a cross-sectional view of the deck along the line of travel. Results are presented. 39582
AbduI-Amir, A.N.; Abdul-Karim, M.A.H.
Microprocessor application to concrete crack depth measurement Journal of Nondestructive Evaluation, Vol. 6, No. 2, pp. 67-72 (Jun. 1987) This work investigates the possibility of utilizing the tx p-8085 microprocessor for concrete crack depth evaluation. For the purpose of the nondestructive testing, Ultrasonic pulses are important for the nondestructive assessment of concrete quality as well as flaw detection and measurement. This method will be useful in repairing concrete columns. 39577
Kim, H.C.; Yoon, S.S.
Ultrasonic measurements during early-stage hydration of ordinary Portland cement Journal of Materials Science, Vol. 23, No. 2, pp. 611-616 The variations of ultrasonic pulse velocity peak amplitude of transmitted pulse and heat evolution rate were measured during the hydration prOCess of ordinary Portland cement with water/cement ratio (W/C ratio) ranging from 0.4 to 0.6 at environmental temperatures between 20 and 400?C. The change of heat evolution rate reflected the kinetics of hydration and was sensitively affected by the W/C ratio and environmental temperature. The velocity and peak amplitude were compared with the heat evolution rate to investigate the correlation of elastic properties and structural development with the kinetics of hydration. The dependence of the velocity and the peak amplitude on W/C ratio and environmental temperature are discussed in terms of the concentration of solid phase in the cement paste varying with W/C ratio and the extent of hydration.
NDT International April 1990
Hara, Tadakatu, lshii, Yugoro; Yoshikawa, Satoshi.
Distribution of pulse velocity and sound pressure in mortar and concrete by ultrasonic test Fifth Pan Pacific Conference on Nondestructive Testing, Vancouver (Canada), Apr. 1987, pp. 220-228. Atomic Energy of Canada Limited. AECL-9394 (Mar. 1987) Investigations of concrete structures showing some distress has been performed to prevent further deterioration. A laboratory investigation of the application of ultrasonic pulse velocity in concrete has been conducted. The authors used a longitudinal wave probe at various frequencies, and found that the frequency has no significant effect in the propagation of pulse velocity in the concrete. Ultrasonic testing in concrete structures has been found to be more convenient when consideing the distribution of the pulse wave, which can define radial propagation direction in the transducer. 40277 Delebarre, C.; Rouvaen, J.M.; Frohly, J.; Bruneel, C. Digital signal processing methods for ultrasonic baekscattered waves in
highly heterogeneous media Proceedings of the I E E E 1987 Ultrasonic Symposium, Denver, Colorado (United States), 14-16 Oct. 1987. Vol. 2, pp. 1053-1056. Edited by B.R. McAvoy. Institute of Electrical and Electronics Engineers. This paper compares two numerical signal processing method which give a signature of highly heterogeneous media based upon the evaluation of mean spacing between the heterogeneities randomly distributed in the medium. The first method is related to the autocorrelation function for the echoes. However, this function doesn't reflect the medium characteristics in the case of highly heterogeneous media: the impulse response of the whole measurement set biases the obtained signature. The second one is derived from the power spectrum of the radio frequency (RF) backscattered signal and gives a non biased signature for red signal and gives a non biased signature for highly heterogeneous media. Data are presented for highly heterogeneous media like concrete. 40165
Goebbels, K.; Dobmann, G.
Localization of steel-reinforcements in concrete: determination of their diameter and cover-thickness measurement by magnetic stray flux Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7A, pp. 533-540. Edited by D . D . T h o m p s o n and D.E.Chimenti, Plenum Press, 1988. An insufficient cover-thickness of concrete is the main reason for corrosion of steel-reinforcements in civil engineering. The volume enlargement of the corroded steel produces stresses at the concrete matrix, initiating cracks, crack growing and finally cover destruction. Codes therefore demand a certain cover-thickness y¢ as function of the steel reinforcement diameter d and the environmental corrosion conditions. A new method is presented to measure the relevant parameters Yc,d non-destructively, based on classical Maxwell- theory: a magnetic field produced by a DC-electromagnetic yoke magnetizes the reinforcement resulting in a stray field. This is measured by an array of Hall-probes situated between the pole shoes. The evaluation leads to the position and diameter of the reinforcement as well as to the cover thickness. The results show that the method meets the practical requirements. 39964 Askegaard, V.; Moiler, P.H. Ultimate load of plain concrete specimens determined nondestruetively N D T International, Vol. 21, No. 6, pp. 427-429 (Dec. 1988) Acceptance of plain concrete specimens, such as large sewers, depends on results of rupture tests carried out on test samples. As such specimens are costly, acoustic emission (AE) has been investigated as a possible method of determining rupture load without unacceptably damaging the specimens, which can then be reused. The AE technique provides an acceptance-rejection criterion and can be used to study the development of strength in newly cast specimens.
Mahadeva lyer, Y.; Srividyara]agopalan, C.; Nayak, N. U.; Suresh Babu, R.H. 39930
Metal depth detec~r Bulletin of Electrochem., Vol. 3, No. 3, pp. 279-280 (May-Jun. 1987) Metal detectors based on eddy current principles find varied applications. They are used in the detection of metals underground, for security purposes, the measurement of cover thickness in reinforced concrete (RCC) structures, etc. This paper describes the design and performance details of such a metal detector used in the measurement of cover thickness of reinforcements in RCC structures.
112
39903
Kozlov, V.N.; Shevaldykin, V.G.; Yakovlev, N.N.
Experimental determination of the attenuation of an ultrasonic wave in concrete Soviet Journal of Nondestructive Testing, Vol. 24, No. 2. pp. 132-140 (Feb. 1988) The basic technical difficulties occurring in experimental determination of the attenuation coefficient of longitudinal ultrasonic vibrations in concrete are analyzed and possible means of overcoming them are shown. Measurements of results for attenuation coefficients at frequencies of 50-300 kHz in concretes. differing in material and panicle size of the coarse filler, are given. 39895
Roy, S.K.; Murthy, C.K.; Krishnamurthy, N.
Statistical study of principal parameters for pulse velocity and compressive strength of concrete Materials Science Forum, Vols. 34-36, No. 2, pp. 1077-1085 (1988). Proceedings of the International Ceramic Conference A U S T C E R A M ' 8 8 Sydney, Australia, 21-26 Aug. 1988. C.C. Sorrell, B. Ben-Nissan (Eds.) This paper is concerned with the statistical analysis of the four dominant parameters affecting concrete strength as related to the pulse velocity, namely: water content, cement content, ageing and cement type. Two types of cement and two levels (low and high) of the other three parameters were investigated by means of 24 factorial experiment. The measured responses for pulse velocity and compressive strength were analysed for statistical significance. 39654
Bussiere, J.F.; Lord, M.; Non, M.
Relation between hardness, microstructure and magnetic coercive force in rail steels Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sop. 1987. Vot. 3, pp. 1863-1869. Pergamon Press, 3173 pp. (1988) Measurements of magnetic coercive force of fully peariitic rail steels having different hardnesses, chemical composition and thermal history are presented between -200 and 6000?C. A pronounced peak in coercive force is generally observed at the Curie temperature of the cementite (FejC) phase, approx 2100?C for.plain carbon rails. This peak shifts rapidly to lower temperatures with small additions of chromium and with heat-treatment, resulting in large changes of I-|c at room temperature, which are unrelated to changes in mechanical properties. Above the Curie temperature of the carbide phase, the coercive force is found to correlate well with hardness regardless of chemical composition and heat-treatment, inferring that in this temperature range both are controlled by the same microstructural parameters, whereas below approx 2100?C the detailed magnetic behavior of the carbide phase has a strong influence on Hsub/c/. 39651
Joyce, R.P.; Koller, G.M.
Rapid non-destructive delamination detection Proceedings of the 16th Symposium on Nondestructive Evaluation, San Antonio, Texas (United States), 21-23 Apr. 1987. pp. 349-361. Nondestructive Testing Information Analysis Center, Texas, USA. Delaminations in concrete bridge decks are a major cause of bridge maintenance problems. While the current sonic methods of testing arc reliable, they are too slow for the survey application. A rapid, non- destructive method for assessing the general condition of the bridge decks without closing the deck to traffic is needed. Electromagnetic sounding, by using pulsed radar, was used in the development of a rapid survey system. This inspection technique can inspect through asphaltic overlays. Creditable surface cover of sand/pebbles, lane marking paint, oil spots and damp pavement have negligible effects on the inspection data. Digital image processing techniques are used to present the individual range scans in a modified B-scan format, providing a cross-sectional view of the deck along the line of travel. Results are presented. 39582
AbduI-Amir, A.N.; Abdul-Karim, M.A.H.
Microprocessor application to concrete crack depth measurement Journal of Nondestructive Evaluation, Vol. 6, No. 2, pp. 67-72 (Jun. 1987) This work investigates the possibility of utilizing the tx p-8085 microprocessor for concrete crack depth evaluation. For the purpose of the nondestructive testing, Ultrasonic pulses are important for the nondestructive assessment of concrete quality as well as flaw detection and measurement. This method will be useful in repairing concrete columns. 39577
Kim, H.C.; Yoon, S.S.
Ultrasonic measurements during early-stage hydration of ordinary Portland cement Journal of Materials Science, Vol. 23, No. 2, pp. 611-616 The variations of ultrasonic pulse velocity peak amplitude of transmitted pulse and heat evolution rate were measured during the hydration prOCess of ordinary Portland cement with water/cement ratio (W/C ratio) ranging from 0.4 to 0.6 at environmental temperatures between 20 and 400?C. The change of heat evolution rate reflected the kinetics of hydration and was sensitively affected by the W/C ratio and environmental temperature. The velocity and peak amplitude were compared with the heat evolution rate to investigate the correlation of elastic properties and structural development with the kinetics of hydration. The dependence of the velocity and the peak amplitude on W/C ratio and environmental temperature are discussed in terms of the concentration of solid phase in the cement paste varying with W/C ratio and the extent of hydration.
NDT International April 1990