Life quality, industrial productivity, and community safety can be assured by the reliability and the safety of infrastructure such as highways, bridges, and energy-supply systems. Reinforced concrete is the most-commonly used massive construction material in urban, road and industrial infrastructure because of its mechanical properties, durability, and mouldability. Concrete has acceptable compressive strength but relatively low tensile strength, so steel reinforcement rods (rebar) are usually added to concrete to enhance its tensile strength. However, steel rebar is subject to the serious and costly problem of corrosion, which eventually can significantly degrade the mechanical properties of concrete. Quantifying the corrosion condition of reinforcing steel can help manage associated risks arising from the unexpected function failure of reinforced concrete structures. In efforts to avoid such failures, engineers rely on quantitative time-history condition monitoring of reinforcing steel to help make decisions on rehabilitation, decommissioning, or replacement of concrete infrastructure. The self-magnetic behaviour of ferromagnetic materials can be used for quantitative condition assessment. Inspection of reinforced concrete structures by a method based on this concept is under development. Improving the data recording, mathematical simulation and interpretation so as to obtain more-reliable outcomes from this novel NDT technology (Passive Magnetic Inspection (PMI)) is the main aim of this research project. This thesis, consisting of eight chapters, investigates various experiments and simulations, and delineates future work: Chapter 1 includes the introduction, theoretical background, and research objectives; Chapter 2 consists of numerical simulations and experimental results on the passive magnetic behavior of a rebar with pitting; Chapter 3 represents the simulations and experimental results of the investigations on rebars with local longitudinal defects; Chapter 4 investigates the self-magnetic behaviour of rebars with different sizes of crack; Chapter 5 covers numerical simulations and experimental results of passive magnetic behavior of an intact rebar and a rebar with general corrosion; Chapter 6 compares the magnetic flux density values generated from rebars with different degrees of general corrosion; Chapter 7 describes a successful fieldwork project; Chapter 8 outlines a general conclusion and future works that can help the further improvement of the inspection technology. To explain the content of the thesis in more detail, through the analysis of magnetic data, Chapters 2, 3, and 4 cover methods for identifying the local defects in steel reinforcements, and Chapters 5 and 6 focus on realizing the general corrosion of steel rebars. Applicable findings generated from Chapter 2 to Chapter 6 are used in detecting and categorizing the local defects and general corrosion in steel rebars. For instance, it is shown that a certain percentile threshold can be applied on magnetic data to accurately detect longitudinal defects. It is also demonstrated that medium and large cracks are detected by magnetic values' absolute gradients of greater than 0.87 (μT/mm) and 0.95 (μT/mm), respectively. In addition, it is shown that the average of standard deviations calculated for a magnetic data set decreases when the degree of general corrosion increases. The findings in the first six chapters are implemented to establish the data gathering, data analysis, and interpretation approaches used in the field work described in Chapter 7. In the field work, the condition of culvert C072's reinforced concrete (RC) bridge structure (located in the north of Markham, Ontario, Canada) is inspected. The inspection, supervised by the Corporation of the City of Markham, uses PMI technology. The inspection outcomes demonstrate that the sections close to the south and north ends of the bridge display the most-severe reinforcement anomalies: roughly, maximums of 20% and 14% of the reinforcement's cross-sectional area loss are detected close to the bridging structure's south and north ends, respectively. Additionally, an area in the middle of the bridge is found to have a noticeable anomaly in the reinforcement. The results generated from the magnetic data, collected using a PMI scanner, are in good agreement with visual-investigation results and the culvert's historical information, such as the concrete's chloride content and compressive strength values, as well as information from a half-cell potential survey. Culvert C072's condition is considered moderately deteriorated and corrective actions are recommended.

MATHEMATICS IN COMPUTATIONAL SCIENCE AND ENGINEERING This groundbreaking new volume, written by industry experts, is a must-have for engineers, scientists, and students across all engineering disciplines working in mathematics and computational science who want to stay abreast with the most current and provocative new trends in the industry. Applied science and engineering is the application of fundamental concepts and knowledge to design, build and maintain a product or a process, which provides a solution to a problem and fulfills a need. This book contains advanced topics in computational techniques across all the major engineering disciplines for undergraduate, postgraduate, doctoral and postdoctoral students. This will also be found useful for professionals in an industrial setting. It covers the most recent trends and issues in computational techniques and methodologies for applied sciences and engineering, production planning, and manufacturing systems. More importantly, it explores the application of computational techniques and simulations through mathematics in the field of engineering and the sciences. Whether for the veteran engineer, scientist, student, or other industry professional, this volume is a must-have for any library. Useful across all engineering disciplines, it is a multifactional tool that can be put to use immediately in practical applications. This groundbreaking new volume: Includes detailed theory with illustrations Uses an algorithmic approach for a unique learning experience Presents a brief summary consisting of concepts and formulae Is pedagogically designed to make learning highly effective and productive Is comprised of peer-reviewed articles written by leading scholars, researchers and professors AUDIENCE: Engineers, scientists, students, researchers, and other professionals working in the field of computational science and mathematics across multiple disciplines

In this era of technological progress and given the need for welfare and safety, everything that is manufactured and maintained must comply with such needs. We would all like to live in a safe house that will not collapse on us. We would all like to walk on a safe road and never see a chasm open in front of us. We would all like to cross a bridge and reach the other side safely. We all would like to feel safe and secure when taking a plane, ship, train, or using any equipment. All this may be possible with the adoption of adequate manufacturing processes, with non-destructive inspection of final parts and monitoring during the in-service life of components. Above all, maintenance should be imperative. This requires effective non-destructive testing techniques and procedures. This Special Issue is a collection of some of the latest research in these areas, aiming to highlight new ideas and ways to deal with challenging issues worldwide. Different types of materials and structures are considered, different non-destructive testing techniques are employed with new approaches for data treatment proposed as well as numerical simulations. This can serve as food for thought for the community involved in the inspection of materials and structures as well as condition monitoring.

Concrete Solutions contains the contributions from some 30 countries to Concrete Solutions, the 6th International Conference on Concrete Repair (Thessaloniki, Greece, 20-23 June 2016). Strengthening and retrofitting are major themes in this volume, with NDT and electrochemical repair following closely, discussing the latest advances and technologies in concrete repair. The book brings together some interesting and challenging theoretical approaches and questions if we really understand and approach such topics as corrosion monitoring correctly. Concrete Solutions is an essential reference work for those working in the concrete repair field, from engineers to architects and from students to clients. The Concrete Solutions Series of international conferences on concrete repair began in 2003 with a conference held in St. Malo, France in association with INSA Rennes. Subsequent conferences have seen the Series partnering with the University of Padua (Italy) in 2009, with TU Dresden (Germany) in 2011 and with Queen’s University Belfast (Northern Ireland) in 2014. In 2016 Thessaloniki (Greece) hosted the conference, partnering with both Aristotle University of Thessaloniki (AUTH) and Democritus University of Thrace (DUTH). The next conference in the series will be held in 2019 in Istanbul.

Nondestructive evaluation of prestressed concrete mainly includes inspection of the condition of the prestressing strands for load rating. This thesis presents a magnetic inspection system to measure main magnetic flux (MMF) and magnetic leakage flux (MFL) signals, to evaluate the condition of prestressing stands. A proof-of-concept has been established using a prototype electromagnet-sensor, showing a direct relationship between the cross-sectional area of the strand and the magnitude of magnetic field induced in it. A field test of a box-beam bridge was conducted using both MMF and MFL detection techniques separately. This led to the realization of a comprehensive MMF-MFL electromagnet-sensor system for inspection of prestressed steel in concrete. A computer aided simulation model was created to model the magnetic field signals and aid in better understanding of the electromagnet-sensor. This model is also useful for generating expected magnetic field signals from magnetization of different strand size and configuration setups and thus, helps in making corrosion estimations. The MMF-MFL signal detection concept was evaluated using the existing electromagnet-sensor in a laboratory setup and on prestressed box-beams obtained from a demolished bridge. It was able to identify corrosion and defects such as breaks or fractures in prestressing strands. For this magnetic inspection system to become practical, certain modifications such as redesign of the magnetic field generated by the magnet to have higher resolution have been suggested. Other features such as accurate measurement of pole face to strand distance and weight reduction have been discussed. The overall outcome of this research has shown that magnetic field signals can be useful to detect hidden corrosion in prestressed box-beams.