The Practical Application of a Flatbed Scanner for Air-Void Characterization of Hardened Concrete PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download The Practical Application of a Flatbed Scanner for Air-Void Characterization of Hardened Concrete PDF full book. Access full book title The Practical Application of a Flatbed Scanner for Air-Void Characterization of Hardened Concrete by Karl Peterson. Download full books in PDF and EPUB format.
Author: Karl Peterson Publisher: ISBN: Category : Air-Void Characterization Languages : en Pages : 23
Book Description
Over the past 30 years, with the advent of computers and digital imaging, many automated systems have been introduced for the purpose of air-void characterization. The majority of the systems employs a contrast-enhancement procedure where a polished cross-section of concrete is darkened with paint, and white powder is forced into the depressions left by air-voids. The system described here follows the same approach and uses a flatbed scanner to collect a single digital image of the entire sample. For all of the systems based on contrast enhancement, the first step is to select a threshold level. Image pixels brighter than the threshold level represent air and image pixels darker than the threshold level represent non-air (i.e., paste or aggregate). Further digital processing steps may be employed but the initial selection of threshold level exerts a strong influence on whether a pixel in the final data set is classified as air or non-air. A systematic approach for threshold determination has been proposed based on an iterative procedure that compares automatically determined air-void parameters to manually determined air-void parameters from a set of training specimens. The calibration procedure finds a single optimum threshold level for the automated system that is to be used for all subsequent analyses. The approach was tested on a population of 88 specimens with manually determined air-void parameters, with the goal of determining an appropriate value for the number of training specimens.
Author: Karl Peterson Publisher: ISBN: Category : Air-Void Characterization Languages : en Pages : 23
Book Description
Over the past 30 years, with the advent of computers and digital imaging, many automated systems have been introduced for the purpose of air-void characterization. The majority of the systems employs a contrast-enhancement procedure where a polished cross-section of concrete is darkened with paint, and white powder is forced into the depressions left by air-voids. The system described here follows the same approach and uses a flatbed scanner to collect a single digital image of the entire sample. For all of the systems based on contrast enhancement, the first step is to select a threshold level. Image pixels brighter than the threshold level represent air and image pixels darker than the threshold level represent non-air (i.e., paste or aggregate). Further digital processing steps may be employed but the initial selection of threshold level exerts a strong influence on whether a pixel in the final data set is classified as air or non-air. A systematic approach for threshold determination has been proposed based on an iterative procedure that compares automatically determined air-void parameters to manually determined air-void parameters from a set of training specimens. The calibration procedure finds a single optimum threshold level for the automated system that is to be used for all subsequent analyses. The approach was tested on a population of 88 specimens with manually determined air-void parameters, with the goal of determining an appropriate value for the number of training specimens.
Author: Karl W. Peterson Publisher: ISBN: Category : Air-voids Languages : en Pages : 16
Book Description
In the province of Ontario, Canada, the Ministry of Transportation administers a quality assurance testing program for all new concrete construction where air content and spacing factor are measured. Testing is performed by qualified operators in accordance with ASTM C457/C457M-12. In this study, 324 routine samples that had been tested by qualified operators were obtained and analyzed for air-void parameters by an alternative automated flatbed scanner method. A strong correlation was found between the manual and automated methods. This research explored the premise that summary statistics from a small set of training samples could be used to define a set of global threshold levels to measure air-void parameters from a much larger population. Two different methods for setting the global thresholds were tested: one based on arithmetic means, and another based on modal location parameters derived from type I extreme value distributions. The frequency of false-negative errors (failure to detect a defect) was used as a criterion to assess the different threshold methods. Automated test results derived using global thresholds based on arithmetic means minimized the occurrence of false-negative events.
Author: Freek P. Bos Publisher: Springer Nature ISBN: 3030499162 Category : Technology & Engineering Languages : en Pages : 1209
Book Description
This book gathers peer-reviewed contributions presented at the 2nd RILEM International Conference on Concrete and Digital Fabrication (Digital Concrete), held online and hosted by the Eindhoven University of Technology, the Netherlands from 6-9 July 2020. Focusing on additive and automated manufacturing technologies for the fabrication of cementitious construction materials, such as 3D concrete printing, powder bed printing, and shotcrete 3D printing, the papers highlight the latest findings in this fast-growing field, addressing topics like mixture design, admixtures, rheology and fresh-state behavior, alternative materials, microstructure, cold joints & interfaces, mechanical performance, reinforcement, structural engineering, durability and sustainability, automation and industrialization.
Author: Alan Poole Publisher: CRC Press ISBN: 1466583827 Category : Architecture Languages : en Pages : 778
Book Description
This classic reference has established the value of petrography as a powerful method for the investigation of concrete as a material. It provides an authoritative and well-illustrated review of concrete composition and textures, including the causes of defects, deterioration, and failure that can be identified using a petrological microscope. This new edition is entirely revised and updated and also greatly extended to take account of new scientific developments and significant improvements in instrumentation and to reflect current laboratory working practices, as well as to reflect new understanding of the performance of concrete and related materials. Now in full color throughout, Concrete Petrography, Second Edition provides case study examples, with appropriate explanatory discussions and practical advice on selecting, handling and preparing specimens. It assists and guides the engineer, the trainee and the experienced petrographer in understanding the scientific evidence that is basic to petrographic analysis and so will lead to more accurate and timely diagnosis and treatment of problems in structural concrete. This book includes: Contributions in specialist areas by internationally recognized experts Explanation of computer techniques as an aid to petrography Full coverage of inspection, sampling, and specimen preparation New sections covering recent technological development of equipment Guidance on observation of cement and concrete mineralogy and microfabrics Discussion and illustrative examples of deterioration and failure mechanisms New work and guidance on the determination of water/cement ratio New color illustrations and micrographs throughout Thorough updating of standards, other authoritative publications, and references A fully revised, extended, and updated glossary of optical and other properties
Author: A. M. Ramezanianpour Publisher: ISBN: Category : Air-Void Characterization Languages : en Pages : 14
Book Description
Air-void analysis of hardened concrete is typically performed according to ASTM C457-09 ["Standard Test Method for Microscopical Determination of Parameters of Air-Void System in Hardened Concrete," Annual Book of ASTM Standards, Vol. 4.2, ASTM International, West Conshohocken, PA], which can be tedious to perform and is operator subjective. Several alternative automated methods have been proposed, two of which are the Rapid Air 457 and the scanner method developed at Michigan Technological University. In each of these methods, images are collected from contrast enhanced surfaces of polished concrete, and image analysis is performed to calculate air-void system parameters. In this research, 22 concrete samples were examined using these two methods, the air-void system parameters were compared to those obtained from the ASTM C457 standard, and the precision of the results was compared to the recommendations of ASTM standard. It was concluded that the total air content and the spacing factor of the air voids measured by Rapid Air 457 and the scanner method were comparable to the air content and the spacing factor measured according to the standard manual method. Considering the fact that the automated image systems could detect air voids smaller in diameter than those typically seen by an operator, it was found that if these small air voids are counted, calculated spacing factors are smaller than those calculated by the manual method. If small diameter air voids are removed from the analysis, then spacing factors agree fairly well with those calculated by ASTM C457 from stereo-optical microscopy.
Author: Anthony Torres Publisher: ISBN: Category : Air-entrained concrete Languages : en Pages : 0
Book Description
The air void system in concrete provides a strong influence on the behavior of cementitious materials in both the fresh and hardened state, especially as it relates to freeze-thaw resistance and deicer scaling. The most common test procedure to characterize the air void system is ASTM C457 – Standard Test method for Microscopical Determination of Parameters of the Air-Void System in Hardened Concrete, which involves microscopic determination of the air content, paste content, air-void size distribution, and spatial dispersion of a sawn concrete sample. This procedure is reliant on the user to make hundreds of critical decisions per sample, which requires significant time, and is potentially subject to human error. Additionally, ASTM C457 provides minimal guidance regarding the exact steps and equipment necessary to prepare a sample for evaluation. The outcome of this research not only provides specific information regarding sample preparation for hardened concrete air void analysis, it also develops an alternative characterization technique that drastically minimizes evaluation time, human error, and increases reliability of key hardened air void characterization parameters. Specific results show on average air void difference of 0.5% and 0.7% between the alternative method versus ASTM C457 Procedure A and B, respectively. The results also show a significant reduction of analysis time from approximately 2 – 4 hours per sample to 15 minutes per sample when using the alternative method.
Author: Karl Peterson
Author: Karl Peterson
Author: Karl W. Peterson
Author: Karl W. Peterson
Author: Jeremy Carlson
Author: Freek P. Bos
Author: Alan Poole
Author: Sona Nezami
Author: A. M. Ramezanianpour
Author: Basil Mark Harris
Author: Anthony Torres