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Acoustic emission crack monitoring and prediction of remaining life of corroding reinforced concrete beams
There is a requirement for radioactive waste producers to ensure the integrity of the cemented wasteform canisters that they produce. Presently available corrosion monitoring and NDT techniques are not readily applicable to cemented canisters. A technique that offers promise in monitoring degradation of a cement wasteform from the outside of a canister is acoustic emission. This report describes the progress of work being carried out to investigate acoustic emission as a monitor of corrosion and degradation of such wasteforms. 4 0 6 5 4 Miyajima, T.; Ogura, Y.; Takishita, T. T r i a l for spectroscopy in ultrasonic testing of concrete (In Japanese) Journal o f Japanese Society for N o n - D e s t r u c t i v e Inspection, Vol. 37, No. 9A, pp. 8 6 9 - 8 7 0 (Sep. 1988) 40292
Hara, Tadakatu, lshii, Yugoro; Yoshikawa, Satoshi.
Distribution of pulse velocity and sound pressure in mortar and concrete by ultrasonic test Fifth Pan Pacific C o n f e r e n c e on Nondestructive Testing, V a n c o u v e r (Canada), Apr. 1987, pp. 220-228. A t o m i c E n e r g y o f C a n a d a Limited, A E C L - 9 3 9 4 (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 considering 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 backscattered waves in highly heterogeneous media Proceedings o f the I E E E 1987 Ultrasonic S y m p o s i u m , Denver, C o l o r a d o (United States), 14-16 Oct. 1987. Vol. 2, pp. 1053-1056. Edited b y B.R. M c A v o y . Institute o f Electrical a n d 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) backseanered 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. 39964
Askegaard, V.; Moiler, P.H.
Ultimate load of plain concrete specimens determined nondestructively N D T International, Vol. 21, No. 6, pp. 4 2 7 - 4 2 9 (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. 39903
Kozlov, V.N.; Shevaldykin, V.G.; Yakovlev, N.N.
Experimental determination of the attenuation of an ultrasonic wave in concrete Soviet Journal o f 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 particle size of the coarse filler, are given. 39895
Roy, S.K.; Murthy, C.K.; Krishnamurthy, N.
39577
Kim, H.C; Yoon, S.S.
Ultrasonic measurements during eariy-stage hydration of ordinary Portland cement Journal o f Materials Science, Vol. 23, No. 2, pp. 6 1 1 - 6 1 6 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 4007C. 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. 39522
Satoshi Teramura; Koichi Tsukiyama; Hideaki Takahashi.
The detection of the fracture of autoclaved aerated concrete during autoclave curing process by acoustic emission Journal o f Acoustic Emission, Vol. 6, No. 4, pp. 2 6 1 - 2 6 6 ( O c t . - D e c . 1987) Autoclaved Aerated Concrete (AAC) occasionally fractures during the autoclave curing in the production process. To study the cause of the fracture, acoustic emission (AE) activities, during autoclave curing, were investigated. When AE events were detected during both temperature rise and fall periods in the autoclave operation of an AAC, the concrete contained a number of microcracks. When AE events were detected only during temperature fall period of an AAC, it was free of microcracks. AE activities during temperature rise period are indicative of the macrocracking. The macrocracking is influenced by the strength of the material just prior to the autoclave curing process. From these results, a procedure for the prevention against fracturing is proposed. 39517
Titus, R.N.K.; Reddy, D.V.; Dunn, S.E.; Hartt, W.H.
Acoustic emission crack monitoring and prediction of remaining fife of corroding reinforced concrete beams Proceedings o f the 4th E u r o p e a n C o n f e r e n c e on Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1031-1040. P e r g a m o n Press, 3173 pp. (1988) Maintenance of reinforced concrete structures requires the detection and characterization of corrosion damage through a diagnostic method. Acoustic emission (AE) testing has proven to be an effective procedure, and possesses the ability to detect the corrosion cracking damage process at an incipient stage. The paper describes the use of acoustic emission for crack monitoring, and prediction of failure life for reinforced concrete members, subjected to varying periods of corrosion. Test beams were subjected to accelerated corrosion by partial submergence in seawater and impressed currents, with the bottom rebars as the anodes, a stainless steel plate as the cathode, and seawater the electrolyte. Piezoelectric ceramic type transducers were glued to the specimen surface at the mid-span top edge. Counts and amplitude distribution of the acoustic emission were monitored at 12 hour intervals. Plots of the amplitude distribution (cumulative and linear) were made just before the memory reached saturation. Correlation studies between AE counts and flexural strength indicated a 95% confidence that the variations in these parameters are interdependent. Correlation studies for other strength characteristics, such as durability and fatigue life, are anticipated to indicate similar trends. 3 9 4 2 4 Hillger, W. I n s p e c t i o n of concrete by u l t r a s o n i c t e s t i n g Proceedings o f the 4th E u r o p e a n C o n f e r e n c e o n Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1003-1012. P e r g a m o n Press, 3173 pp. (1988) This article reports the investigations to enhance the informative value of the ultrasonic NDT of concrete. The object of the investigations was the defectoseopy, i.e. the monitoring of homogeneity and detection of localized faults. The testing technique was further developed with regard to amplitude evaluation. A US-inspection system "Sonograf 1000" was developed for this purpose. This new flaw detector automatically evaluates the amplitude with a gated digital logarithmic peak detector, the time of flight and the frequency spectrum of the received signal, so that it became possible to record C-scans of precast concrete components by fully automatic procedure. C-scans clearly show the artificially introduced defects and the homogeneity of the material.
Statistical study of principal parameters for pulse velocity and compressive strength of concrete
Damage measurement via ultrasonic method
Materials Science F o r u m , Vols. 34-36, No. 2, pp. 1077-1085 (1988). Proceedings o f the International C e r a m i c C o n f e r e n c e A U S T C E R A M ' 8 8 S y d n e y , Australia, 2 1 - 2 6 A u g . 1988. C.C. Sorrell, B. B e n - N i s s a n (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.
Proceedings o f the 4th E u r o p e a n C o n f e r e n c e on Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1013-1023. P e r g a m o n Press, 3173 pp. (1988) A special ultrasonic testing method has been developed to measure damage in concrete structures. This technique, which is closely related to the presence of microcracks and/or micropores, takes account of the particular micro-structure of concrete. The first part of this study demonstrates the great influence of the particular nature of undamaged concrete on wave propagation. The second part consists in the analysis of the effects of mechanical damage and specially of its anisotropy.
39582
Abdul-Amir, A.N.; Abdul-Karim, M.A.H.
Microprocessor application to concrete crack depth measurement Journal o f Nondestructive Evaluation, Vol. 6, No. 2, pp. 6 7 - 7 2 (Jun. 1987) This work investigates the possibility of utilizing the tt 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.
N D T & E International October 1991
39423
39367
Berthaud, Y.
Teramura, S.; Tsukiyama, K.; Takahashi, H.
Evaluation of fracture toughness of autoclaved lightweight concrete by means of acoustic emission technique Journal o f Acoustic Emission, Vol. 7, No. 1, pp. 1-8 ( J a n J M a r . 1988) The quality of an autoclaved aerated concrete has usually been evaluated by the mechanical strength, such as compressive strength and bending strength. These mechanical properties, however, are not appropriate for the evaluation of the fragility of the concrete, because the fragility depends strongly upon the crack nucleation and
273
Hara, Tadakatu, lshii, Yugoro; Yoshikawa, Satoshi.
Distribution of pulse velocity and sound pressure in mortar and concrete by ultrasonic test Fifth Pan Pacific C o n f e r e n c e on Nondestructive Testing, V a n c o u v e r (Canada), Apr. 1987, pp. 220-228. A t o m i c E n e r g y o f C a n a d a Limited, A E C L - 9 3 9 4 (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 considering 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 backscattered waves in highly heterogeneous media Proceedings o f the I E E E 1987 Ultrasonic S y m p o s i u m , Denver, C o l o r a d o (United States), 14-16 Oct. 1987. Vol. 2, pp. 1053-1056. Edited b y B.R. M c A v o y . Institute o f Electrical a n d 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) backseanered 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. 39964
Askegaard, V.; Moiler, P.H.
Ultimate load of plain concrete specimens determined nondestructively N D T International, Vol. 21, No. 6, pp. 4 2 7 - 4 2 9 (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. 39903
Kozlov, V.N.; Shevaldykin, V.G.; Yakovlev, N.N.
Experimental determination of the attenuation of an ultrasonic wave in concrete Soviet Journal o f 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 particle size of the coarse filler, are given. 39895
Roy, S.K.; Murthy, C.K.; Krishnamurthy, N.
39577
Kim, H.C; Yoon, S.S.
Ultrasonic measurements during eariy-stage hydration of ordinary Portland cement Journal o f Materials Science, Vol. 23, No. 2, pp. 6 1 1 - 6 1 6 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 4007C. 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. 39522
Satoshi Teramura; Koichi Tsukiyama; Hideaki Takahashi.
The detection of the fracture of autoclaved aerated concrete during autoclave curing process by acoustic emission Journal o f Acoustic Emission, Vol. 6, No. 4, pp. 2 6 1 - 2 6 6 ( O c t . - D e c . 1987) Autoclaved Aerated Concrete (AAC) occasionally fractures during the autoclave curing in the production process. To study the cause of the fracture, acoustic emission (AE) activities, during autoclave curing, were investigated. When AE events were detected during both temperature rise and fall periods in the autoclave operation of an AAC, the concrete contained a number of microcracks. When AE events were detected only during temperature fall period of an AAC, it was free of microcracks. AE activities during temperature rise period are indicative of the macrocracking. The macrocracking is influenced by the strength of the material just prior to the autoclave curing process. From these results, a procedure for the prevention against fracturing is proposed. 39517
Titus, R.N.K.; Reddy, D.V.; Dunn, S.E.; Hartt, W.H.
Acoustic emission crack monitoring and prediction of remaining fife of corroding reinforced concrete beams Proceedings o f the 4th E u r o p e a n C o n f e r e n c e on Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1031-1040. P e r g a m o n Press, 3173 pp. (1988) Maintenance of reinforced concrete structures requires the detection and characterization of corrosion damage through a diagnostic method. Acoustic emission (AE) testing has proven to be an effective procedure, and possesses the ability to detect the corrosion cracking damage process at an incipient stage. The paper describes the use of acoustic emission for crack monitoring, and prediction of failure life for reinforced concrete members, subjected to varying periods of corrosion. Test beams were subjected to accelerated corrosion by partial submergence in seawater and impressed currents, with the bottom rebars as the anodes, a stainless steel plate as the cathode, and seawater the electrolyte. Piezoelectric ceramic type transducers were glued to the specimen surface at the mid-span top edge. Counts and amplitude distribution of the acoustic emission were monitored at 12 hour intervals. Plots of the amplitude distribution (cumulative and linear) were made just before the memory reached saturation. Correlation studies between AE counts and flexural strength indicated a 95% confidence that the variations in these parameters are interdependent. Correlation studies for other strength characteristics, such as durability and fatigue life, are anticipated to indicate similar trends. 3 9 4 2 4 Hillger, W. I n s p e c t i o n of concrete by u l t r a s o n i c t e s t i n g Proceedings o f the 4th E u r o p e a n C o n f e r e n c e o n Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1003-1012. P e r g a m o n Press, 3173 pp. (1988) This article reports the investigations to enhance the informative value of the ultrasonic NDT of concrete. The object of the investigations was the defectoseopy, i.e. the monitoring of homogeneity and detection of localized faults. The testing technique was further developed with regard to amplitude evaluation. A US-inspection system "Sonograf 1000" was developed for this purpose. This new flaw detector automatically evaluates the amplitude with a gated digital logarithmic peak detector, the time of flight and the frequency spectrum of the received signal, so that it became possible to record C-scans of precast concrete components by fully automatic procedure. C-scans clearly show the artificially introduced defects and the homogeneity of the material.
Statistical study of principal parameters for pulse velocity and compressive strength of concrete
Damage measurement via ultrasonic method
Materials Science F o r u m , Vols. 34-36, No. 2, pp. 1077-1085 (1988). Proceedings o f the International C e r a m i c C o n f e r e n c e A U S T C E R A M ' 8 8 S y d n e y , Australia, 2 1 - 2 6 A u g . 1988. C.C. Sorrell, B. B e n - N i s s a n (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.
Proceedings o f the 4th E u r o p e a n C o n f e r e n c e on Non-Destructive Testing, L o n d o n (United K i n g d o m ) , 13-17 Sep. 1987. Vol. 2, pp. 1013-1023. P e r g a m o n Press, 3173 pp. (1988) A special ultrasonic testing method has been developed to measure damage in concrete structures. This technique, which is closely related to the presence of microcracks and/or micropores, takes account of the particular micro-structure of concrete. The first part of this study demonstrates the great influence of the particular nature of undamaged concrete on wave propagation. The second part consists in the analysis of the effects of mechanical damage and specially of its anisotropy.
39582
Abdul-Amir, A.N.; Abdul-Karim, M.A.H.
Microprocessor application to concrete crack depth measurement Journal o f Nondestructive Evaluation, Vol. 6, No. 2, pp. 6 7 - 7 2 (Jun. 1987) This work investigates the possibility of utilizing the tt 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.
N D T & E International October 1991
39423
39367
Berthaud, Y.
Teramura, S.; Tsukiyama, K.; Takahashi, H.
Evaluation of fracture toughness of autoclaved lightweight concrete by means of acoustic emission technique Journal o f Acoustic Emission, Vol. 7, No. 1, pp. 1-8 ( J a n J M a r . 1988) The quality of an autoclaved aerated concrete has usually been evaluated by the mechanical strength, such as compressive strength and bending strength. These mechanical properties, however, are not appropriate for the evaluation of the fragility of the concrete, because the fragility depends strongly upon the crack nucleation and
273