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Frequency spectrum analysis of ultrasonic testing signal in concrete
N DT Abstracts sonic and ultrasonic pulse echo (UPE) measurements in concrete.
cementitious material types and curing conditions. Normal portland cement, blast-furnace slag cement and silica fume are used individually or in combination. Results show that: a) silica fume in concrete increases the pulse velocity; b) pulse velocity and strength are lower for air-cured concrete than for water-cured concrete; and c) the relationship between strength and pulse velocity is given by an exponential curve which is less influenced by curing or cementitious material types. Evaluation of in-situ concrete strength based on paste efficiency concept is examined.
Measurements were made to demonstrate that the frequencies generated by these types of impacts are in the proper range for making UPE measurements in concrete, i.e. less than 200 kHz. Also, it was demonstrated that the energy level from these impact sources was high, suitable for penetrating large distances.
AI Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete b r i d g e s relative to reinforcement corrosion. Volume 4. Deck membrance effectiveness and a method for evaluating, membrane i n t e g r i t y 53482
Wei-Du,L. Frequency spectrum analysis of ultrasonic testing signal in concrete 52711
Virginia Polytechnic Inst. and State Univ., Blacksburg (United States), PB93-142990/GAR, 152pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of this study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion, when properly installed and overlaid with at least 2.5-in. (6.4-cm) hot-mix asphalt, which should be kept in a good service condition. An average life of 40 years is expected for preformed membrane systems and an increase of 25 years in bridge deck life is expected.
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 104-114. Edited by F. Ansari and S. Sture. A S C E (1992) Description is given on high-speed sample apparatus connected with the CTS-25 low frequency ultrasonoscope and computer, the time domain of ultrasonic testing signal is transformed to the frequency domain by way of Fast Fourier Transform. Study of frequency spectrum analysis has been carried out for compact concrete, loose concrete and concrete with voids.
Popovics,S.; Popovics, J.S. A critique of the ultrasonic pulse velocity method for testing concrete 52710
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 94-103. Edited by F. Ansari and S. Sture. A S C E (1992) This paper is a critical analysis of the existing ultrasonic pulse, velocity method as well as an attempt to explain it's failure for strength determination and damage detection in concrete. Experimental data are presented that demonstrate the insensitivity of the ultrasonic pulse velocity method to the present strength of a variety of materials including concretes, mortars, and pastes.
Andrews, D.R. Future prospects for ultrasonic inspection of concrete 53477
Proceedings o f the Institution o f Civil Engineers, Structures and Buildings, Vol. 99, No. 1, pp. 71-73 (1993) The attractiveness of ultrasonic inspection methods is considered, with reference to factors such as accuracy, convenience, capital cost, cost per inspection, and safety. Recent progress in transducer design and computer interpretation is out-lined in relation to the identification of potential future developments.
52709 Ghorbanpoor, A.; Virmani, Y.P.; Fatemi, G.R. E v a l u a t i o n of concrete bridges by impact-echo Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 82-93. Edited by F. Ansari and S. Sture. A S C E (1992) This study has examined the application and further development of a non-destructive evaluation technique, the Impact-Echo for determination of location and extent of voids in the ducts of post-tensioned bridge structural members. Theoretical laboratory, and field studies have been performed and it has been demonstrated that it is possible to detect, with high reliability, the location and extent of voids in the post-tensioning ducts of concrete structures. It was found that information corresponding to the location of voids within concrete members may readily be obtained by examining the wave reflection frequency values, from an induced impact at the surface of the member, due to the wave incidents at the free boundaries of these voids.
53419 Luong, M.P.; Liu, H. Nonlinear dynamic analysis of damage in concrete Fracture M e c h a n i c s o f Concrete Structures. Edited by Z.P. Bazant. pp. 645-650 Elsevier A p p l i e d Science (1992) ISBN 1851668691 This paper describes experimental results, obtained in the laboratory, using specific testing methods to assess damage accumulation. The damaging process of a concrete specimen has been detected by analysing the signal evolution of ultrasonic pulses travelling through the specimen subject to increasing loads. A nonlinear analyser based on a multidimensional Fourier transform permits to separate the linear and nonlinear part of the concrete response.
Al Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete bridges relative to reinforcement corrosion. Volume 4. Deck membrane effectiveness and a method for evaluating membrane i n t e g r i t y 52925
Olson, L.D. Sonic NDE of structural concrete 52708
Nondestructive Testing o f Concrete E l e m e n t s and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 70-81. Edited by F. Ansari and S. Sture. A S C E (1992) Case histories are presented to illustrate applications of nondestructive evaluation (NDE) methods that use stress waves to characterize the conditions of concrete construction. The case histories discuss the following NDE methods and applications: 1. Impact Echo to evaluate cracking in a 1923 thin-arch concrete dam on the downstream face; 2. Impact Echo to investigate honeycomb and void conditions, and to provide quality assurance of repairs to a box girder bridge; and 3. Ultrasonic Pulse Velocity to define the severity of cracking damage in pre-cast bridge segments and for quality assurance of epoxy injection repairs. NDE methods accurately defined the extent and nature of sound and defective concrete conditions.
Virginia Polytechnic Inst. and State Univ., Blacksburg, Virginia (United States), PB93-116911/GAR, 150pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of the study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion when properly installed and overlaid with at least 2.5 in. (6.4 cm) of hot-mix asphalt, which should be kept in good service condition. An average life of 40 years is expected for preformed membrane systems, and an increase of 25 years in bridge deck life is expected.
Sztukiewicz, R.J. Ultrasonic imaging of the asphaltic concrete surface layer 52694
Acoustical Imaging. Vol. 19, pp. 601-605. Edited by H. Ermert and H.P. Harjes. Plenum Press (1992) The author is conducting works in the field of applying ultrasonic methods for describing the condition of the surface layer of flexible pavement. He is also observing the changes which take place in the surface layer in time, using both destructive and non-destructive methods. The purpose of this work is to present the testing results from 1984-89 in the form of an ultrasonic image of the surface layer of flexible pavement. The author also intends to demonstrate the influence of traffic lanes and measuring sections on the parameters of the ultrasonic longitudinal wave propagation by means of variance analysis.
Sri Ravindrarajah, R. Evaluation of compressive strength for high-strength concrete by pulse velocity method 52712
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 115-126. Edited by F. Ansari and S. Sture. A S C E (1992) Development of compressive strength and pulse velocity for highstrength concrete from the age of 5 hours are studied in relation to
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cementitious material types and curing conditions. Normal portland cement, blast-furnace slag cement and silica fume are used individually or in combination. Results show that: a) silica fume in concrete increases the pulse velocity; b) pulse velocity and strength are lower for air-cured concrete than for water-cured concrete; and c) the relationship between strength and pulse velocity is given by an exponential curve which is less influenced by curing or cementitious material types. Evaluation of in-situ concrete strength based on paste efficiency concept is examined.
Measurements were made to demonstrate that the frequencies generated by these types of impacts are in the proper range for making UPE measurements in concrete, i.e. less than 200 kHz. Also, it was demonstrated that the energy level from these impact sources was high, suitable for penetrating large distances.
AI Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete b r i d g e s relative to reinforcement corrosion. Volume 4. Deck membrance effectiveness and a method for evaluating, membrane i n t e g r i t y 53482
Wei-Du,L. Frequency spectrum analysis of ultrasonic testing signal in concrete 52711
Virginia Polytechnic Inst. and State Univ., Blacksburg (United States), PB93-142990/GAR, 152pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of this study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion, when properly installed and overlaid with at least 2.5-in. (6.4-cm) hot-mix asphalt, which should be kept in a good service condition. An average life of 40 years is expected for preformed membrane systems and an increase of 25 years in bridge deck life is expected.
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 104-114. Edited by F. Ansari and S. Sture. A S C E (1992) Description is given on high-speed sample apparatus connected with the CTS-25 low frequency ultrasonoscope and computer, the time domain of ultrasonic testing signal is transformed to the frequency domain by way of Fast Fourier Transform. Study of frequency spectrum analysis has been carried out for compact concrete, loose concrete and concrete with voids.
Popovics,S.; Popovics, J.S. A critique of the ultrasonic pulse velocity method for testing concrete 52710
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 94-103. Edited by F. Ansari and S. Sture. A S C E (1992) This paper is a critical analysis of the existing ultrasonic pulse, velocity method as well as an attempt to explain it's failure for strength determination and damage detection in concrete. Experimental data are presented that demonstrate the insensitivity of the ultrasonic pulse velocity method to the present strength of a variety of materials including concretes, mortars, and pastes.
Andrews, D.R. Future prospects for ultrasonic inspection of concrete 53477
Proceedings o f the Institution o f Civil Engineers, Structures and Buildings, Vol. 99, No. 1, pp. 71-73 (1993) The attractiveness of ultrasonic inspection methods is considered, with reference to factors such as accuracy, convenience, capital cost, cost per inspection, and safety. Recent progress in transducer design and computer interpretation is out-lined in relation to the identification of potential future developments.
52709 Ghorbanpoor, A.; Virmani, Y.P.; Fatemi, G.R. E v a l u a t i o n of concrete bridges by impact-echo Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 82-93. Edited by F. Ansari and S. Sture. A S C E (1992) This study has examined the application and further development of a non-destructive evaluation technique, the Impact-Echo for determination of location and extent of voids in the ducts of post-tensioned bridge structural members. Theoretical laboratory, and field studies have been performed and it has been demonstrated that it is possible to detect, with high reliability, the location and extent of voids in the post-tensioning ducts of concrete structures. It was found that information corresponding to the location of voids within concrete members may readily be obtained by examining the wave reflection frequency values, from an induced impact at the surface of the member, due to the wave incidents at the free boundaries of these voids.
53419 Luong, M.P.; Liu, H. Nonlinear dynamic analysis of damage in concrete Fracture M e c h a n i c s o f Concrete Structures. Edited by Z.P. Bazant. pp. 645-650 Elsevier A p p l i e d Science (1992) ISBN 1851668691 This paper describes experimental results, obtained in the laboratory, using specific testing methods to assess damage accumulation. The damaging process of a concrete specimen has been detected by analysing the signal evolution of ultrasonic pulses travelling through the specimen subject to increasing loads. A nonlinear analyser based on a multidimensional Fourier transform permits to separate the linear and nonlinear part of the concrete response.
Al Qadi, I.L.; Weyers, R.E.; Galagedera, N.L.; Cady, P.D. Condition evaluation of concrete bridges relative to reinforcement corrosion. Volume 4. Deck membrane effectiveness and a method for evaluating membrane i n t e g r i t y 52925
Olson, L.D. Sonic NDE of structural concrete 52708
Nondestructive Testing o f Concrete E l e m e n t s and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 70-81. Edited by F. Ansari and S. Sture. A S C E (1992) Case histories are presented to illustrate applications of nondestructive evaluation (NDE) methods that use stress waves to characterize the conditions of concrete construction. The case histories discuss the following NDE methods and applications: 1. Impact Echo to evaluate cracking in a 1923 thin-arch concrete dam on the downstream face; 2. Impact Echo to investigate honeycomb and void conditions, and to provide quality assurance of repairs to a box girder bridge; and 3. Ultrasonic Pulse Velocity to define the severity of cracking damage in pre-cast bridge segments and for quality assurance of epoxy injection repairs. NDE methods accurately defined the extent and nature of sound and defective concrete conditions.
Virginia Polytechnic Inst. and State Univ., Blacksburg, Virginia (United States), PB93-116911/GAR, 150pp. (Sep. 1992) An intensive investigation was conducted to evaluate membrane performance and effectiveness. The main objectives of the study were to: develop a nondestructive test method for evaluating the integrity of membranes in place; investigate the effectiveness of membranes, relative to chloride barrier properties, as a function of membrane integrity; and evaluate the factors that may affect membrane performance, including membrane type and age, climate, and deicer application rate. A nondestructive methodology using ultrasonic pulse velocity was developed to predict the membrane status. The laboratory study and field validation concluded that preformed membrane systems reduce chloride intrusion when properly installed and overlaid with at least 2.5 in. (6.4 cm) of hot-mix asphalt, which should be kept in good service condition. An average life of 40 years is expected for preformed membrane systems, and an increase of 25 years in bridge deck life is expected.
Sztukiewicz, R.J. Ultrasonic imaging of the asphaltic concrete surface layer 52694
Acoustical Imaging. Vol. 19, pp. 601-605. Edited by H. Ermert and H.P. Harjes. Plenum Press (1992) The author is conducting works in the field of applying ultrasonic methods for describing the condition of the surface layer of flexible pavement. He is also observing the changes which take place in the surface layer in time, using both destructive and non-destructive methods. The purpose of this work is to present the testing results from 1984-89 in the form of an ultrasonic image of the surface layer of flexible pavement. The author also intends to demonstrate the influence of traffic lanes and measuring sections on the parameters of the ultrasonic longitudinal wave propagation by means of variance analysis.
Sri Ravindrarajah, R. Evaluation of compressive strength for high-strength concrete by pulse velocity method 52712
Nondestructive Testing o f Concrete Elements and Structures, San Antonio, Texas (United States), 13-15 Apr. 1992, pp. 115-126. Edited by F. Ansari and S. Sture. A S C E (1992) Development of compressive strength and pulse velocity for highstrength concrete from the age of 5 hours are studied in relation to
260