Ultrasonic Testing to Determine Water-Cement Ratio for Freshly Mixed Concrete


Book Description

The objective of the research presented here was to find promising directions for the development of ultrasonic test method(s) for the direct, instantaneous determination of the water-cement ratio (W/C) in fresh mortar or concrete. The importance of W/C is related to potential strength development and, to a certain extent, the durability potential of the hardened concrete. Since previous efforts during the past 50 years have been unsuccessful in testing fresh concrete due to the complexity of the problem, innovative, high-risk/high-gain methods were selected in the present work. The methods are considered innovative since a literature search detected no sign that they have been used for testing fresh concrete before.







Advanced Techniques for Testing of Cement-Based Materials


Book Description

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.










Testing During Concrete Construction


Book Description

Testing concrete while construction is underway enables decisions to be made which can improve the quality of the finished structure. The book covers testing and measuring techniques for fresh concrete and concrete during the first few days after placing, and for reinforcement and prestressing tendons. Many examples are given of practical methods w







Acoustical Imaging


Book Description

Acoustical imaging has become an indispensable tool in a variety of fields. Since its introduction, the applications have grown and cover a variety of techniques, producing significant results in fields as disparate as medicine and seismology. Cutting-edge trends continue to be discussed worldwide. This book contains the proceedings of the 27th International Symposium on Acoustical Imaging (AI27), which took place in Saarbrücken, Germany, from March 24th to March 27th 2003. The Symposium belongs to a conference series in existence since 1968. AI27 comprised sessions on: Medical Imaging, Non-Destructive Testing, Seismic Imaging, Physics and Mathematics of Acoustical Imaging, Acoustic Microscopy. During two well-attended workshops the applications of quantitative acoustical imaging in biology and medical applications, and in near-field imaging of materials, were discussed. Based on its cross-disciplinary aspects, the authors of the papers of AI27 present experiments, theory and construction of new instruments.




Acoustic Emission Testing


Book Description

This book provides an introduction to Acoustic Emission Testing and its applications to different materials like concrete, steel, ceramics, geotechnical materials, polymers, biological structures and wood. Acoustic Emission Techniques (AET) techniques have been studied in engineering for a long time. The techniques are applied more and more to practical investigations and are more and more standardized in codes. This is because the degradation of structures due to ageing urgently demand for maintenance and rehabilitation of structures in service. It results in the need for the development of advanced and efficient inspection techniques. In mechanical engineering and concerning the monitoring of machines and mechanical components, AE is a widely accepted observing deterioration in the frame of structural health monitoring. The advantages of AE like sensitivity, damage localization potential, non-intrusive nature as well as developments in signal analysis and data transmission allow applications that could not be considered decades ago. As such, AE techniques draw great attention to diagnostic applications and in material testing. This book covers all levels from the description of AE basics for AE beginners (level of a student) to sophisticated AE algorithms and applications to real large-scale structures as well as the observation of the cracking process in laboratory specimen to study fracture processes. This book has proved its worth over the past twelve years. Now in its second edition, it will be a resource that sets the standard and equips readers for the future. All chapters from the 1st edition have been updated and rewritten and eight extra chapters (e.g also regarding AE tomography, AE in plate-like structures and AE for investigations of hardening of fresh concrete) have been added.