Download or read book Condition Assessment of Cemented Materials Using Ultrasonic Surface Waves written by Ahmet Serhan Kırlangıç and published by . This book was released on 2013 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical waves provide information about the stiffness and the condition of a medium; thus, changes in medium conditions can be inferred from changes in wave velocity and attenuation. Non-destructive testing (NDT) methods based on ultrasonic waves are often more economical, practical and faster than destructive testing. Multichannel analysis of surface waves (MASW) is a well-established surface wave method used for determination of the shear-wave profile of layered medium. The MASW test configuration is also applicable to assess the condition of concrete elements using appropriate frequency range. Both attenuation and dispersion of ultrasonic waves can be evaluated by this technique. In ultrasonic testing, the characterization of a medium requires the precise measurement of its response to ultrasonic pulses to infer the presence of defects and boundary conditions. However, any ultrasonic transducer attached to a surface affects the measured response; especially at high frequencies. On the other hand, ultrasonic transducers available for engineering application are mostly used to measure wave velocities (travel time method). Therefore, these transducers do not have a flat response in the required frequency range. Moreover, in the case of full-waveform methods, the recorded signals should be normalized with respect to the transfer functions of the transducers to obtain the real response of the tested specimen. The main objective of this research is to establish a comprehensive methodology based on surface wave characteristics (velocity, attenuation and dispersion) for condition assessment of cemented materials with irregular defects. To achieve the major objective, the MASW test configuration is implemented in the ultrasonic frequency range. The measured signals are subjected to various signal processing techniques to extract accurate information. In addition, a calibration procedure is conducted to determine the frequency response functions (FRF) of the piezoelectric accelerometers outside their nominal frequency range. This calibration is performed using a high-frequency laser vibrometer. This research includes three main studies. The first study introduces the calibration approach to measure the FRFs of the accelerometers outside of their flat frequency range. The calibrated accelerometers are then used to perform MASW tests on a cemented-sand medium. The original signals and the corrected ones by eliminating the effect of the FRFs are used to determine material damping of the medium. Although, the damping ratios obtained from different accelerometers are not same, the values from the corrected signals are found closer to the characteristic damping value compared to those from the uncorrected signals. The second study investigates the sensitivity of Rayleigh wave velocity, attenuation coefficient, material damping and dispersion in phase velocity to evaluate the sensitivity of these characteristics to the damage quantity in a medium. The soft cemented-sand medium is preferred as the test specimen so that well-defined shaped defects could be created in the medium. MASW test configuration is implemented on the medium for different cases of defect depth. The recorded signals are processed using different signal processing techniques including Fourier and wavelet transforms and empirical mode decomposition to determine the surface wave characteristics accurately. A new index, 'dispersion index', is introduced which quantifies the defect based on the dispersive behaviour. All surface wave characteristics are found capable of reflecting the damage quantity of the test medium at different sensitivity levels. In the final study, the condition assessment of six lab-scale concrete beams with different void percent is performed. The beam specimens involving Styrofoam pellets with different ratios are tested under ultrasonic and mechanical equipment. The assessment produce established in the second study with well-defined defects is pursed for the beams with irregular defects. Among the characteristics, attenuation, P and R-wave velocities and dispersion index are found as the promising characteristics for quantifying the defect volume.

Download or read book Condition Assessment of Cementitious Materials Using Surface Waves in Ultrasonic Frequency Range written by Ahmet Serhan K?rlang?ç and published by . This book was released on 2015 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface waves propagating in a medium provide information about the mechanical properties and condition of the material. Variations in the material condition can be inferred from changes in the surface wave characteristics. Multichannel analysis of surface waves (MASW) is a well-established surface wave method used for determination of the shear-wave profile of the soil layers near the surface. The MASW test configuration is also applicable to assess the condition of construction materials using appropriate frequency range. Previous studies on the detection of surface-breaking cracks in concrete elements, using the dispersion and attenuation of ultrasonic waves, were successful; however, a complete damage assessment of the whole element was not in the scope of these studies. In this study, different wave characteristics, such as Rayleigh wave velocity, wave attenuation, and phase velocity dispersion, are investigated to evaluate their sensitivity to the damage in a medium. The condition of a test specimen, which is a half-space medium made of cement and sand, is evaluated using ultrasonic transducers for different damage cases. The recorded signals are processed using the Fourier and wavelet transforms to determine the surface wave characteristics. A new dispersion index (DI) is introduced, which represents the global correlation between the dispersion of phase velocity and damage level. All features are found to be capable of reflecting the damage in the test medium with different levels of sensitivity. Among the investigated parameters, the proposed dispersion index shows high sensitivity and linear correlation with the damage.

Download or read book Condition Assessment of Concrete Elements Through Two Nondestructive Ultrasonic Techniques written by María José Rodríguez Roblero and published by . This book was released on 2017 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reinforced concrete is one of the materials most used in civil infrastructure, and the expected service life is generally for several decades. However, as any other material, concrete performance is affected by environmental conditions, the normal use of the structure, ageing and extreme load events. All of these factors affect the elements performance and can induce damage. Since all infrastructure components deteriorate over time, it is needed to assess their actual condition. Moreover, to implement adequate corrective measures it is needed to first detect damage and quantify its extent. There are different methods that may be used to inspect concrete elements, and the selection of the adequate technique depends on the property of interest and the available resources. Among the available inspection methods, the nondestructive techniques (NDT) are those used to detect defects, to estimate the material properties or to assess the integrity of components that do not affect the elements under evaluation. Every inspection technique has advantages and disadvantages; and consequently, the current trend is to use a combination of methods. Even though several nondestructive methods are commercially available, currently there is no comprehensive method to evaluate concrete columns. Taking in consideration these aspects, the main objective of this research was to develop a new nondestructive methodology and testing device that would allow inspecting concrete columns in a fast and reliable manner, without affecting their future performance. The proposed methodology relies on ultrasonic tests. The condition evaluation is based on measurements of wave velocity and wave attenuation because it is known that the attenuation is more sensitive to damage than the velocity. However, wave attenuation is generally not used in site evaluations because is very difficult to ensure consistent measurements in the field. To overcome this limitation, a new ultrasonic testing device was developed and tested. To verify the applicability of the methodology, reinforced and unreinforced concrete samples were tested in the laboratory, and a sample of in-service reinforced concrete columns was also evaluated. The main contributions of the research presented in this thesis are: The construction of a new ultrasonic field testing device to test structural elements with circular cross section. The evaluation of a new methodology to evaluate concrete elements based on statistical indexes computed from wave velocity and wave attenuation by testing a sample of in-service columns. The new methodology allows detecting damage at earlier stages which would allow implementing opportune corrective measures. The proposal and evaluation of an alternative testing procedure to evaluate freeze/thaw damage in concrete specimens based on wave attenuation measurements. The appraisal of a new procedure to monitor progressive damage in concrete elements using surface wave measurements. The evaluation of alternative signal processing techniques of the signals obtained from the surface wave testing to facilitate the analysis of the results.

Download or read book Non destructive Testing and Evaluation of Civil Engineering Structures written by Jean-Paul Balayssac and published by Elsevier. This book was released on 2017-11-22 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: The non-destructive evaluation of civil engineering structures in reinforced concrete is becoming an increasingly important issue in this field of engineering. This book proposes innovative ways to deal with this problem, through the characterization of concrete durability indicators by the use of non-destructive techniques. It presents the description of the various non-destructive techniques and their combination for the evaluation of indicators. The processing of data issued from the combination of NDE methods is also illustrated through examples of data fusion methods. The identification of conversion models linking observables, obtained from non-destructive measurements, to concrete durability indicators, as well as the consideration of different sources of variability in the assessment process, are also described. An analysis of in situ applications is carried out in order to highlight the practical aspects of the methodology. At the end of the book the authors provide a methodological guide detailing the proposed non-destructive evaluation methodology of concrete indicators. - Presents the latest developments performed in the community of NDT on different aspects - Provides a methodology developed in laboratory and transferred onsite for the evaluation of concrete properties which are not usually addressed by NDT methods - Includes the use of data fusion for merging the measurements provided by several NDT methods - Includes examples of current and potential applications

Download or read book Nondestructive Testing of Materials and Structures written by Oral Büyüköztürk and published by Springer Science & Business Media. This book was released on 2012-09-14 with total page 1231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Condition assessment and characterization of materials and structures by means of nondestructive testing (NDT) methods is a priority need around the world to meet the challenges associated with the durability, maintenance, rehabilitation, retrofitting, renewal and health monitoring of new and existing infrastructures including historic monuments. Numerous NDT methods that make use of certain components of the electromagnetic and acoustic spectrum are currently in use to this effect with various levels of success and there is an intensive worldwide research effort aimed at improving the existing methods and developing new ones. The knowledge and information compiled in this book captures the current state of the art in NDT methods and their application to civil and other engineering materials and structures. Critical reviews and advanced interdisciplinary discussions by world-renowned researchers point to the capabilities and limitations of the currently used NDT methods and shed light on current and future research directions to overcome the challenges in their development and practical use. In this respect, the contents of this book will equally benefit practicing engineers and researchers who take part in characterization, assessment and health monitoring of materials and structures.

Download or read book Non Destructive Assessment of Concrete Structures Reliability and Limits of Single and Combined Techniques written by Denys Breysse and published by Springer Science & Business Media. This book was released on 2012-01-20 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives information on non destructive techniques for assessment of concrete structures. It synthesizes the best of international knowledge about what techniques can be used for assessing material properties (strength) and structural properties (geometry, defects...). It describes how the techniques can be used so as to answer a series of usual questions, highlighting their capabilities and limits, and providing advices for a better use of techniques. It also focuses on possible combinations of techniques so as to improve the assessment. It is based on many illustrative examples and give in each case references to standards and guidelines.

Download or read book Non Destructive Testing of Structures written by Magdalena Rucka and published by MDPI. This book was released on 2021-02-16 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Special Issue “Non-Destructive Testing of Structures” has been proposed to present the recent developments in the field of the diagnostics of structural materials and components in civil and mechanical engineering. The papers highlighted in this editorial concern various aspects of non-invasive diagnostics, including such topics as the condition assessments of civil and mechanical structures and the connections of structural elements, the inspection of cultural heritage monuments, the testing of structural materials, structural health monitoring systems, the integration of non-destructive testing methods, advanced signal processing for the non-destructive testing of structures (NDT), damage detection and damage imaging, as well as modeling and numerical analyses for supporting structural health monitoring (SHM) systems.

Download or read book Nondestructive Testing to Identify Concrete Bridge Deck Deterioration written by and published by Transportation Research Board. This book was released on 2013 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: " TRB's second Strategic Highway Research Program (SHRP 2) Report S2-R06A-RR-1: Nondestructive Testing to Identify Concrete Bridge Deck Deterioration identifies nondestructive testing technologies for detecting and characterizing common forms of deterioration in concrete bridge decks.The report also documents the validation of promising technologies, and grades and ranks the technologies based on results of the validations.The main product of this project will be an electronic repository for practitioners, known as the NDToolbox, which will provide information regarding recommended technologies for the detection of a particular deterioration. " -- publisher's description.

Download or read book Cement based Materials Characterization Using Ultrasonic Attenuation written by Wonsiri Punurai and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantitative nondestructive evaluation (NDE) of cement-based materials is a critical area of research that is leading to advances in the health monitoring and condition assessment of the civil infrastructure. Ultrasonic NDE has been implemented with varying levels of success to characterize cement-based materials with complex microstructure and damage. A major issue with the application of ultrasonic techniques to characterize cement-based materials is their inherent inhomogeneity at multiple length scales. Ultrasonic waves propagating in these materials exhibit a high degree of attenuation losses, making quantitative interpretations difficult. Physically, these attenuation losses are a combination of internal friction in a viscoelastic material (ultrasonic absorption), and the scattering losses due to the material heterogeneity. The objective of this research is to use ultrasonic attenuation to characterize the microstructure of heterogeneous cement-based materials. The study considers a real, but simplified cement-based material, cement paste - a common bonding matrix of all cement-based composites. Cement paste consists of Portland cement and water but does not include aggregates. First, this research presents the findings of a theoretical study that uses a set of existing acoustics models to quantify the scattered ultrasonic wavefield from a known distribution of entrained air voids. These attenuation results are then coupled with experimental measurements to develop an inversion procedure that directly predicts the size and volume fraction of entrained air voids in a cement paste specimen. Optical studies verify the accuracy of the proposed inversion scheme. These results demonstrate the effectiveness of using attenuation to measure the average size, volume fraction of entrained air voids and the existence of additional larger entrapped air voids in hardened cement paste. Finally, coherent and diffuse ultrasonic waves are used to develop a direct relationship between attenuation and water to cement (w/c) ratio. A phenomenological model based on the existence of fluid-filled capillary voids is used to help explain the experimentally observed behavior. Overall this research shows the potential of using ultrasonic attenuation to quantitatively characterize cement paste. The absorption and scattering losses can be related to the individual microstructural elements of hardened cement paste. By taking a fundamental, mechanics-based approach, it should be possible to add additional components such as scattering by aggregates or even microcracks in a systematic fashion and eventually build a realistic model for ultrasonic wave propagation study for concrete.

Download or read book Advanced Techniques for Testing of Cement Based Materials written by Marijana Serdar and published by Springer Nature. This book was released on 2020-02-18 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book examines advanced, non-standardized techniques that have been developed for determining different properties of cement paste, mortar and concrete, and provides state-of-the-art information on methods for monitoring hydration-induced changes in cement-based materials (CBMs). These methods are often nondestructive and allow quasi-continuous monitoring covering the time span from placement of the material to formation of a fully hardened cement composite. The book also presents various applications of acoustic emission for characterizing fresh concrete, recent developments in ultrasonic methods for characterizing CBMs since placement, application of ambient response methods for measuring elastic modulus, methods for determining deformational characteristics of CBMs since setting and methods for in situ measurements of stresses in concrete elements during hardening.

Download or read book Journal of Research of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1988 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Non destructive Testing of Materials in Civil Engineering written by Krzysztof Schabowicz and published by MDPI. This book was released on 2019-11-19 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book was proposed and organized as a means to present recent developments in the field of nondestructive testing of materials in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of nondestructive testing of different materials in civil engineering—from building materials to building structures. The current trend in the development of nondestructive testing of materials in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. From this point of view, interesting results with significance for building practices have been obtained

Download or read book Maintenance Safety Risk Management and Life Cycle Performance of Bridges written by Nigel Powers and published by CRC Press. This book was released on 2018-07-04 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges contains lectures and papers presented at the Ninth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2018), held in Melbourne, Australia, 9-13 July 2018. This volume consists of a book of extended abstracts and a USB card containing the full papers of 393 contributions presented at IABMAS 2018, including the T.Y. Lin Lecture, 10 Keynote Lectures, and 382 technical papers from 40 countries. The contributions presented at IABMAS 2018 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of bridge maintenance, safety, risk, management and life-cycle performance. Major topics include: new design methods, bridge codes, heavy vehicle and load models, bridge management systems, prediction of future traffic models, service life prediction, residual service life, sustainability and life-cycle assessments, maintenance strategies, bridge diagnostics, health monitoring, non-destructive testing, field testing, safety and serviceability, assessment and evaluation, damage identification, deterioration modelling, repair and retrofitting strategies, bridge reliability, fatigue and corrosion, extreme loads, advanced experimental simulations, and advanced computer simulations, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of more rational decision-making on bridge maintenance, safety, risk, management and life-cycle performance of bridges for the purpose of enhancing the welfare of society. The Editors hope that these Proceedings will serve as a valuable reference to all concerned with bridge structure and infrastructure systems, including students, researchers and engineers from all areas of bridge engineering.

Download or read book Structural Condition Assessment written by Robert T. Ratay and published by John Wiley & Sons. This book was released on 2005-01-17 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Structural Condition Assessment, editor-in-chief Robert T. Ratay gathers together the leading people in the field to produce the first unified resource on all aspects of structural condition assessment for strength, serviceability, restoration, adaptive reuse, code compliance, and vulnerability. Organized by the four main stages of a structural evaluation, this book provides an introduction to structural deterioration and its consequences, the business and legal aspects of conducting an evaluation, initial survey and evaluation techniques for various structures, and specific tests for five of the most common structural materials (concrete, steel, masonry, timber and fabric.)

Download or read book Concrete Repair Rehabilitation and Retrofitting IV written by Frank Dehn and published by CRC Press. This book was released on 2015-09-17 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fourth International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2015) was held 5-7 October 2015 in Leipzig, Germany. This conference is a collaborative venture by researchers from the South African Research Programme in Concrete Materials (based at the Universities of Cape Town and The Witwatersrand) and the Material

Download or read book NEHRP Commentary on the Gidelines for the Seismic Rehabilitation of Buildings written by Eugene Zeller and published by DIANE Publishing. This book was released on 2000-06 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document from the National Earthquake Hazards Reduction Program (NEHRP) was prepared for the Building Seismic Safety Council (BSSC) with funding from the Federal Emergency Management Agency (FEMA). It provides commentary on the NEHRP Guidelines for the Seismic Rehabilitation of Buildings. It contains systematic guidance enabling design professionals to formulate effective & reliable rehabilitation approaches that will limit the expected earthquake damage to a specified range for a specified level of ground shaking. This kind of guidance applicable to all types of existing buildings & in all parts of the country has never existed before. Illustrated.

Download or read book Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements written by William G. Buttlar and published by Springer. This book was released on 2018-05-26 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Premature cracking in asphalt pavements and overlays continues to shorten pavement lifecycles and creates significant economic and environmental burden. In response, RILEM Technical Committee TC 241-MCD on Mechanisms of Cracking and Debonding in Asphalt and Composite Pavements has conducted a State-of-the-Art Review (STAR), as detailed in this comprehensive book. Cutting-edge research performed by RILEM members and their international partners is presented, along with summaries of open research questions and recommendations for future research. This book is organized according to the theme areas of TC 241-MCD - i.e., fracture in the asphalt bulk material, interface debonding behaviour, and advanced measurement systems. This STAR is expected to serve as a long term reference for researchers and practitioners, as it contributes to a deeper fundamental understanding of the mechanisms behind cracking and debonding in asphalt concrete and composite pavement systems.