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Modelling concrete damage by acoustic emission
Information which refines and complements the method of inspecting parts by means of the MIB-4 device is provided. The results obtained in testing this equipment abroad are given.
Mo Da-Wei; Liu Yi-Si; Guo Zhi-Ping; An Fu-Liu; Zhang Ghao-Zong; Miao Qi-Tian.
37890
Neutron radiography study in Tsinghua University Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 87-94. D. Reidel Publishing Company Neutron radiography research described in this paper was performed at the research reactor of Tsinghua University, which is a pool-type light water reactor with a power of 2 MW. Work carried out included the development of neutron radiographic convertors, neutron radiography of corn roots growing in soil and an investigation of water permeation in concrete. A preliminary real-time neutron radiography system which can be used to observe two-phase flow was installed.
Mo Dawei; Zhang Chaozong; Guo Zhiping; Liu Yisi; An Fulin; Mio Quitian.
37882
The application of neutron radiography to the measurement of the water- permeability of concrete Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 263-270. D. Reidel Publishing Company The water-permeability of concrete is a significant factor for dams, offshore platforms, bridges etc. This paper describes the use of neutron radiography in conjunction with the traditional fixed pressure technique for determining water permeability in concrete.
Abdul Ghaffar Ramli; Azali Muhamad; Rosly Jaafar; Sheriffa Noor Khamseah. 37840
Status of neutron radiography in Malaysia Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 69-78. D. Reidel Publishing Company The development of neutron radiography (NR) in Malaysia began with the availability of the country's first research reactor. The Reaktor TRIGA PUSPATI (RTP) was commissioned in June 1982 and plans to construct the neutron radiography facility commenced soon after that. In late 1983, a NR test facility (NuR 1) was constructed out of small modular concrete blocks. Tests carried out in this facility enabled the design of the permanent facility (NuR 2) to be finalized. The construction of NuR 2 took place in November 1984 and it was completed in February 1985. NuR 2 is now actively used in developmental work in NR to ensure that an efficient local NR service can be given in the near future. A number of shortcomings in the design of NuR 2 have been identified, and efforts to rectify these are under way. 37745 Hopwood, T.; Deen, R.C. Periodic nondestructive evaluation of in-service metal bridges Kentucky Transportation Research Program, Lexington, Kentucky (United States), PB87--194452, 31 pp. (Mar. 1984). Not held at Harwell. Metal bridges are subject to in-service fracture problems mainly caused by fatigue. The report considers the prevention of bridge failure by the performance of periodic nondestructive evaluations. Differences in visual and other nondestructive inspections are discussed. The use of preliminary inspection strategies for proper testing also is presented. The suitability of common types of nondestructive testing for bridge inspections also are included. 37736 Anon Non-destructive tests for concrete BSI News, pp. 16-17 (Nov. 1987) A new British Standard for concrete is to be introduced which takes into account advances in new equipment and testing techniques, computerised data analysis and better understanding of the relationship between test results and physical parameters. 37693
Ohtsu, M.
Acoustic emission characteristics in concrete and diagnostic applications Journal of Acoustic Emission, Vol. 6, No. 2, pp. 99-108 (Apr./Jun. 1987) We have studied basic properties of acoustic emission (AE) in concrete, including stress dependence of AE events, Kaiser effect, amplitude distribution, and frequency spectra. On the basis of these results, we applied AE to the diagnosis of cracking in concrete structures. Applications encompass the three-dimensional source location, the evaluation of deterioration by testing of core-drilled specimens, and the prediction of crack propagation based on the boundary element method (BEM). 37657 Bekeshko, N.A. Thermal monitoring for building materials Soviet Journal of Nondestructive Testing, Vol. 23, No. 2, pp. 140-142 (Oct. 1987) Experiments have been performed on one-sided thermal monitoring for building materials (concrete, wood, and brick) with uniform distributed surface heating and the observation of a thermal image and the recording of thermal profiles.
NDT International April 1990
37600 N=jjar, W.S. The ~ t =rid apldication of neutron radiography to study concrete, with emphasis on nicrocrackin¢ Dissertation Abstracts International, Vol. 48, No. 1, p. 211 (Jill. 1987) Neutron radiography has been successfully developed and used as a testing method for studying microcracking in concrete. The microcracks in a polished concrete specimen are partially impregnated with a "contrast agent" and subsequently exposed to a neutron flux. The contrast agent is a material with a relatively high neutron attenuation capacity compared to concrete. Gadolinium has been used as the neutron-attenuating contrast agent, which is applied to a polished concrete surface in the form of an aqueous solution of gadolinium nitrate. When a neutron flux is passed through the specimen, neutrons are readily attenuated by the gadolinium in the cracks, which results in a sharp difference in the flux emanating from the cracked and uncracked areas. The resulting radiographs show cracks which are not visible to the unaided eye when directly observing the concrete specimens themselves. Air voids are also identified due to their partial impregnation with the contrast agent. The method is evaluated by comparing it with the more conventional X-ray radiography technique. Neutron radiography appears to be more effective than Xradiography for the identification and study of microcracking in concrete. An analytical model is developed which supports the experimental results. Neutron radiography is successfully applied to study and measure the incidence of microcracking in concrete cylinders as a function of load. 37539 Ellway, K. Pile integrity testing - a misunderstood technology Ground Engineering, Vol. 20, No. 6, pp. 2, 6 (Sep. 1987) The fundamental capabilities and limitations of hammer or vibration based pile integrity tests are set out in detail, as this technique is frequently misunderstood and misused. However pile integrity testing can provide a measure of confidence in the constructed quality of bored piles and is of considerable value to civil engineers dealing with nondestructive evaluation.
Lange, Yu.V.; Ustinov, E.G.; Shlyaktsu, M.L; Abramovskii, V.R.; Vityuk, P.S.
37536
IPB-10UTs Instrument for the nondestructive strength evaluation of concrete by the impact method Soviet Journal of Nondestructive Testing, Vol. 23, No. 2, pp. 120-124 (Oct. 1987) An instrument for impact testing of the strength of concrete is described. The structure of the measurement transducer is discussed, and a block diagram is given for digital processing of the measurement results. The instrument is tested on concrete samples of various strengths. 37490
Yamada, K.; Kosaka, Y.
Damping characteristics of acoustic emission propagating through concrete (In Japanese) Japan Society of Materials Science Journal, Vol. 36, No. 406, pp. 716722 (Jul. 1987) The damping characteristics of acoustic emission propagating through concrete was examined experimentally in order to establish the method of acoustic emission source wave analysis. The parameters chosen in the investigation were the effect of holding technique of sensor (Experiment-l), the effects of shape and size of specimen (Experiment- II), the effect of degree of heterogeneity of material (Experiment- III), and the effect of the degree of accumulative damage of specimen (Experiment-IV), respectively. 37471 Berthelot, J.M.; Robert, J.L. Modeling concrete damage by acoustic emission Journal of Acoustic Emission, Vol. 6, No. 1, pp. 43-60 (Jan./Mar. 1987) Acoustic emission has been used to monitor concrete damage within various specimens. Four acoustic emission transducers are used to locate the fracture mechanisms. Histograms of the amplitude, duration and number of events are also obtained from one of the transducers, following parametric filtering. The homogenized mechanical behavior of a representative volume of concrete shows three stages, which can be characterized by a damage coefficient. The amplitude filtering allows estimation of the distribution of concrete damage and its monitoring during a mechanical test.
AI-Chlabi, A.R.; Raouf, W.Z.A.; Al-Tak, H.H.; Abdul Karim, M.A.H. 37314
Concrete strength uitrasoqie digital tester Journal of Nondestructive Evaluation, Vol. 5, No. 3/4, pp. 157-160 (Dec. 1986) This paper describes the design and construction of a concrete strength ultrasonic digital meter. The method depends on the transmission and reception of two ultrasonic sinusoidal signals. These two signals are so processed so as to yield a digital output number representative of the speed of propagation through the concrete specimen. This velocity figure can be related to the applications on finding the concrete crush strength, concrete crack depth, as well as the concrete behavior with electrical curing temperature. The electronic system employs Complementary-Oxide Semiconductor logic circuits and hybrid conversion circuits. It consumes such a little power, which makes such a design transportable and hence a battery operated device. 37250 Muravin, G.B.; Gur'ev, V.V. Kaiser effect and structural state of concrete
115
Mo Da-Wei; Liu Yi-Si; Guo Zhi-Ping; An Fu-Liu; Zhang Ghao-Zong; Miao Qi-Tian.
37890
Neutron radiography study in Tsinghua University Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 87-94. D. Reidel Publishing Company Neutron radiography research described in this paper was performed at the research reactor of Tsinghua University, which is a pool-type light water reactor with a power of 2 MW. Work carried out included the development of neutron radiographic convertors, neutron radiography of corn roots growing in soil and an investigation of water permeation in concrete. A preliminary real-time neutron radiography system which can be used to observe two-phase flow was installed.
Mo Dawei; Zhang Chaozong; Guo Zhiping; Liu Yisi; An Fulin; Mio Quitian.
37882
The application of neutron radiography to the measurement of the water- permeability of concrete Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 263-270. D. Reidel Publishing Company The water-permeability of concrete is a significant factor for dams, offshore platforms, bridges etc. This paper describes the use of neutron radiography in conjunction with the traditional fixed pressure technique for determining water permeability in concrete.
Abdul Ghaffar Ramli; Azali Muhamad; Rosly Jaafar; Sheriffa Noor Khamseah. 37840
Status of neutron radiography in Malaysia Neutron Radiography, Proceedings of the Second World Conference, Paris (France), 16-20 Jun. 1986. pp. 69-78. D. Reidel Publishing Company The development of neutron radiography (NR) in Malaysia began with the availability of the country's first research reactor. The Reaktor TRIGA PUSPATI (RTP) was commissioned in June 1982 and plans to construct the neutron radiography facility commenced soon after that. In late 1983, a NR test facility (NuR 1) was constructed out of small modular concrete blocks. Tests carried out in this facility enabled the design of the permanent facility (NuR 2) to be finalized. The construction of NuR 2 took place in November 1984 and it was completed in February 1985. NuR 2 is now actively used in developmental work in NR to ensure that an efficient local NR service can be given in the near future. A number of shortcomings in the design of NuR 2 have been identified, and efforts to rectify these are under way. 37745 Hopwood, T.; Deen, R.C. Periodic nondestructive evaluation of in-service metal bridges Kentucky Transportation Research Program, Lexington, Kentucky (United States), PB87--194452, 31 pp. (Mar. 1984). Not held at Harwell. Metal bridges are subject to in-service fracture problems mainly caused by fatigue. The report considers the prevention of bridge failure by the performance of periodic nondestructive evaluations. Differences in visual and other nondestructive inspections are discussed. The use of preliminary inspection strategies for proper testing also is presented. The suitability of common types of nondestructive testing for bridge inspections also are included. 37736 Anon Non-destructive tests for concrete BSI News, pp. 16-17 (Nov. 1987) A new British Standard for concrete is to be introduced which takes into account advances in new equipment and testing techniques, computerised data analysis and better understanding of the relationship between test results and physical parameters. 37693
Ohtsu, M.
Acoustic emission characteristics in concrete and diagnostic applications Journal of Acoustic Emission, Vol. 6, No. 2, pp. 99-108 (Apr./Jun. 1987) We have studied basic properties of acoustic emission (AE) in concrete, including stress dependence of AE events, Kaiser effect, amplitude distribution, and frequency spectra. On the basis of these results, we applied AE to the diagnosis of cracking in concrete structures. Applications encompass the three-dimensional source location, the evaluation of deterioration by testing of core-drilled specimens, and the prediction of crack propagation based on the boundary element method (BEM). 37657 Bekeshko, N.A. Thermal monitoring for building materials Soviet Journal of Nondestructive Testing, Vol. 23, No. 2, pp. 140-142 (Oct. 1987) Experiments have been performed on one-sided thermal monitoring for building materials (concrete, wood, and brick) with uniform distributed surface heating and the observation of a thermal image and the recording of thermal profiles.
NDT International April 1990
37600 N=jjar, W.S. The ~ t =rid apldication of neutron radiography to study concrete, with emphasis on nicrocrackin¢ Dissertation Abstracts International, Vol. 48, No. 1, p. 211 (Jill. 1987) Neutron radiography has been successfully developed and used as a testing method for studying microcracking in concrete. The microcracks in a polished concrete specimen are partially impregnated with a "contrast agent" and subsequently exposed to a neutron flux. The contrast agent is a material with a relatively high neutron attenuation capacity compared to concrete. Gadolinium has been used as the neutron-attenuating contrast agent, which is applied to a polished concrete surface in the form of an aqueous solution of gadolinium nitrate. When a neutron flux is passed through the specimen, neutrons are readily attenuated by the gadolinium in the cracks, which results in a sharp difference in the flux emanating from the cracked and uncracked areas. The resulting radiographs show cracks which are not visible to the unaided eye when directly observing the concrete specimens themselves. Air voids are also identified due to their partial impregnation with the contrast agent. The method is evaluated by comparing it with the more conventional X-ray radiography technique. Neutron radiography appears to be more effective than Xradiography for the identification and study of microcracking in concrete. An analytical model is developed which supports the experimental results. Neutron radiography is successfully applied to study and measure the incidence of microcracking in concrete cylinders as a function of load. 37539 Ellway, K. Pile integrity testing - a misunderstood technology Ground Engineering, Vol. 20, No. 6, pp. 2, 6 (Sep. 1987) The fundamental capabilities and limitations of hammer or vibration based pile integrity tests are set out in detail, as this technique is frequently misunderstood and misused. However pile integrity testing can provide a measure of confidence in the constructed quality of bored piles and is of considerable value to civil engineers dealing with nondestructive evaluation.
Lange, Yu.V.; Ustinov, E.G.; Shlyaktsu, M.L; Abramovskii, V.R.; Vityuk, P.S.
37536
IPB-10UTs Instrument for the nondestructive strength evaluation of concrete by the impact method Soviet Journal of Nondestructive Testing, Vol. 23, No. 2, pp. 120-124 (Oct. 1987) An instrument for impact testing of the strength of concrete is described. The structure of the measurement transducer is discussed, and a block diagram is given for digital processing of the measurement results. The instrument is tested on concrete samples of various strengths. 37490
Yamada, K.; Kosaka, Y.
Damping characteristics of acoustic emission propagating through concrete (In Japanese) Japan Society of Materials Science Journal, Vol. 36, No. 406, pp. 716722 (Jul. 1987) The damping characteristics of acoustic emission propagating through concrete was examined experimentally in order to establish the method of acoustic emission source wave analysis. The parameters chosen in the investigation were the effect of holding technique of sensor (Experiment-l), the effects of shape and size of specimen (Experiment- II), the effect of degree of heterogeneity of material (Experiment- III), and the effect of the degree of accumulative damage of specimen (Experiment-IV), respectively. 37471 Berthelot, J.M.; Robert, J.L. Modeling concrete damage by acoustic emission Journal of Acoustic Emission, Vol. 6, No. 1, pp. 43-60 (Jan./Mar. 1987) Acoustic emission has been used to monitor concrete damage within various specimens. Four acoustic emission transducers are used to locate the fracture mechanisms. Histograms of the amplitude, duration and number of events are also obtained from one of the transducers, following parametric filtering. The homogenized mechanical behavior of a representative volume of concrete shows three stages, which can be characterized by a damage coefficient. The amplitude filtering allows estimation of the distribution of concrete damage and its monitoring during a mechanical test.
AI-Chlabi, A.R.; Raouf, W.Z.A.; Al-Tak, H.H.; Abdul Karim, M.A.H. 37314
Concrete strength uitrasoqie digital tester Journal of Nondestructive Evaluation, Vol. 5, No. 3/4, pp. 157-160 (Dec. 1986) This paper describes the design and construction of a concrete strength ultrasonic digital meter. The method depends on the transmission and reception of two ultrasonic sinusoidal signals. These two signals are so processed so as to yield a digital output number representative of the speed of propagation through the concrete specimen. This velocity figure can be related to the applications on finding the concrete crush strength, concrete crack depth, as well as the concrete behavior with electrical curing temperature. The electronic system employs Complementary-Oxide Semiconductor logic circuits and hybrid conversion circuits. It consumes such a little power, which makes such a design transportable and hence a battery operated device. 37250 Muravin, G.B.; Gur'ev, V.V. Kaiser effect and structural state of concrete
115