Author: Norb Delatte
Publisher: Elsevier
ISBN: 1845697030
Category : Technology & Engineering
Languages : en
Pages : 352
Book Description
Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques.Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete.With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. - Provides a review of concrete deterioration and damage - Discusses condition assessment and repair techniques, standards and guidelines
Failure, Distress and Repair of Concrete Structures
Author: Norb Delatte
Publisher: Elsevier
ISBN: 1845697030
Category : Technology & Engineering
Languages : en
Pages : 352
Book Description
Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques.Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete.With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. - Provides a review of concrete deterioration and damage - Discusses condition assessment and repair techniques, standards and guidelines
Publisher: Elsevier
ISBN: 1845697030
Category : Technology & Engineering
Languages : en
Pages : 352
Book Description
Understanding and recognising failure mechanisms in concrete is a fundamental pre-requisite to determining the type of repair, or whether a repair is feasible. This title provides a review of concrete deterioration and damage, as well as looking at the problem of defects in concrete. It also discusses condition assessment and repair techniques.Part one discusses failure mechanisms in concrete and covers topics such as causes and mechanisms of deterioration in reinforced concrete, types of damage in concrete structures, types and causes of cracking and condition assessment of concrete structures. Part two reviews the repair of concrete structures with coverage of themes such as standards and guidelines for repairing concrete structures, methods of crack repair, repair materials, bonded concrete overlays, repairing and retrofitting concrete structures with fiber-reinforced polymers, patching deteriorated concrete structures and durability of repaired concrete.With its distinguished editor and international team of contributors, Failure and repair of concrete structures is a standard reference for civil engineers, architects and anyone working in the construction sector, as well as those concerned with ensuring the safety of concrete structures. - Provides a review of concrete deterioration and damage - Discusses condition assessment and repair techniques, standards and guidelines
Steel Corrosion-Induced Concrete Cracking
Author: Yuxi Zhao
Publisher: Butterworth-Heinemann
ISBN: 0128092106
Category : Technology & Engineering
Languages : en
Pages : 206
Book Description
Steel Corrosion Induced Concrete Cracking presents the latest advances in the origin, mechanism and development of corrosion-induced cracking in concrete. It investigates topics including expansion coefficient and elastic modulus of steel corrosion, rust layer and rust distribution, spatial distribution of corrosion products, the shape of corrosion-induced cracks and so on. This book concludes by proposing an improved corrosion-induced cracking model, which considers the phenomena of the simultaneous occurrence of corrosion layer accumulation and corrosion filling in concrete. This book will be a valuable reference book for researchers and graduate students in the field of concrete durability and concrete structure, and industry engineers who are concerned with the deterioration mechanisms and the life cycle of reinforced concrete structures. - Proposes a new corrosion-induced concrete cracking model, which takes into account the phenomenon of the simultaneous occurrence of corrosion layer accumulation and corrosion filling paste. - Investigates the parameters and values of expansion coefficients and elastic modulus of steel corrosion, which enables a more rational prediction of concrete surface cracking - Introduces the use of the Gaussian function to describe the non-uniform spatial distribution of corrosion products.
Publisher: Butterworth-Heinemann
ISBN: 0128092106
Category : Technology & Engineering
Languages : en
Pages : 206
Book Description
Steel Corrosion Induced Concrete Cracking presents the latest advances in the origin, mechanism and development of corrosion-induced cracking in concrete. It investigates topics including expansion coefficient and elastic modulus of steel corrosion, rust layer and rust distribution, spatial distribution of corrosion products, the shape of corrosion-induced cracks and so on. This book concludes by proposing an improved corrosion-induced cracking model, which considers the phenomena of the simultaneous occurrence of corrosion layer accumulation and corrosion filling in concrete. This book will be a valuable reference book for researchers and graduate students in the field of concrete durability and concrete structure, and industry engineers who are concerned with the deterioration mechanisms and the life cycle of reinforced concrete structures. - Proposes a new corrosion-induced concrete cracking model, which takes into account the phenomenon of the simultaneous occurrence of corrosion layer accumulation and corrosion filling paste. - Investigates the parameters and values of expansion coefficients and elastic modulus of steel corrosion, which enables a more rational prediction of concrete surface cracking - Introduces the use of the Gaussian function to describe the non-uniform spatial distribution of corrosion products.
Application of Fracture Mechanics to Cementitious Composites
Author: S.P. Shah
Publisher: Springer Science & Business Media
ISBN: 9400951213
Category : Science
Languages : en
Pages : 701
Book Description
Portland cement concrete is a relatively brittle material. As a result, mechanical behavior of concrete, conventionally reinforced concrete, prestressed concrete, and fiber reinforced concrete is critically influenced by crack propagation. It is, thus, not surprising that attempts are being made to apply the concepts of fracture mechanics to quantify the resistance to cracking in cementious composites. The field of fracture mechanics originated in the 1920's with A. A. Griffith's work on fracture of brittle materials such as glass. Its most significant applications, however, have been for controlling brittle fracture and fatigue failure of metallic structures such as pressure vessels, airplanes, ships and pipe lines. Considerable development has occurred in the last twenty years in modifying Griffith's ideas or in proposing new concepts to account for the ductility typical of metals. As a result of these efforts, standard testing techniques have been available to obtain fracture parameters for metals, and design based on these parameters are included in relevant specifications. Many attempts have been made, in the last two decades or so, to apply the fracture mechanics concepts to cement, mortar, con crete and reinforced concrete. So far, these attempts have not led to a unique set of material parameters which can quantify the resistance of these cementitious composites to fracture. No standard testing methods and a generally accepted theoretical analysis are established for concrete as they are for metals.
Publisher: Springer Science & Business Media
ISBN: 9400951213
Category : Science
Languages : en
Pages : 701
Book Description
Portland cement concrete is a relatively brittle material. As a result, mechanical behavior of concrete, conventionally reinforced concrete, prestressed concrete, and fiber reinforced concrete is critically influenced by crack propagation. It is, thus, not surprising that attempts are being made to apply the concepts of fracture mechanics to quantify the resistance to cracking in cementious composites. The field of fracture mechanics originated in the 1920's with A. A. Griffith's work on fracture of brittle materials such as glass. Its most significant applications, however, have been for controlling brittle fracture and fatigue failure of metallic structures such as pressure vessels, airplanes, ships and pipe lines. Considerable development has occurred in the last twenty years in modifying Griffith's ideas or in proposing new concepts to account for the ductility typical of metals. As a result of these efforts, standard testing techniques have been available to obtain fracture parameters for metals, and design based on these parameters are included in relevant specifications. Many attempts have been made, in the last two decades or so, to apply the fracture mechanics concepts to cement, mortar, con crete and reinforced concrete. So far, these attempts have not led to a unique set of material parameters which can quantify the resistance of these cementitious composites to fracture. No standard testing methods and a generally accepted theoretical analysis are established for concrete as they are for metals.
Corrosion of Steel in Concrete
Author: Luca Bertolini
Publisher: John Wiley & Sons
ISBN: 3527651713
Category : Technology & Engineering
Languages : en
Pages : 389
Book Description
Steel-reinforced concrete is used ubiquitously as a building material due to its unique combination of the high compressive strength of concrete and the high tensile strength of steel. Therefore, reinforced concrete is an ideal composite material that is used for a wide range of applications in structural engineering such as buildings, bridges, tunnels, harbor quays, foundations, tanks and pipes. To ensure durability of these structures, however, measures must be taken to prevent, diagnose and, if necessary, repair damage to the material especially due to corrosion of the steel reinforcement. The book examines the different aspects of corrosion of steel in concrete, starting from basic and essential mechanisms of the phenomenon, moving up to practical consequences for designers, contractors and owners both for new and existing reinforced and prestressed concrete structures. It covers general aspects of corrosion and protection of reinforcement, forms of attack in the presence of carbonation and chlorides, problems of hydrogen embrittlement as well as techniques of diagnosis, monitoring and repair. This second edition updates the contents with recent findings on the different topics considered and bibliographic references, with particular attention to recent European standards. This book is a self-contained treatment for civil and construction engineers, material scientists, advanced students and architects concerned with the design and maintenance of reinforced concrete structures. Readers will benefit from the knowledge, tools, and methods needed to understand corrosion in reinforced concrete and how to prevent it or keep it within acceptable limits.
Publisher: John Wiley & Sons
ISBN: 3527651713
Category : Technology & Engineering
Languages : en
Pages : 389
Book Description
Steel-reinforced concrete is used ubiquitously as a building material due to its unique combination of the high compressive strength of concrete and the high tensile strength of steel. Therefore, reinforced concrete is an ideal composite material that is used for a wide range of applications in structural engineering such as buildings, bridges, tunnels, harbor quays, foundations, tanks and pipes. To ensure durability of these structures, however, measures must be taken to prevent, diagnose and, if necessary, repair damage to the material especially due to corrosion of the steel reinforcement. The book examines the different aspects of corrosion of steel in concrete, starting from basic and essential mechanisms of the phenomenon, moving up to practical consequences for designers, contractors and owners both for new and existing reinforced and prestressed concrete structures. It covers general aspects of corrosion and protection of reinforcement, forms of attack in the presence of carbonation and chlorides, problems of hydrogen embrittlement as well as techniques of diagnosis, monitoring and repair. This second edition updates the contents with recent findings on the different topics considered and bibliographic references, with particular attention to recent European standards. This book is a self-contained treatment for civil and construction engineers, material scientists, advanced students and architects concerned with the design and maintenance of reinforced concrete structures. Readers will benefit from the knowledge, tools, and methods needed to understand corrosion in reinforced concrete and how to prevent it or keep it within acceptable limits.
Steel Corrosion in Concrete
Author: Arnon Bentur
Publisher: CRC Press
ISBN: 9780419225300
Category : Technology & Engineering
Languages : en
Pages : 214
Book Description
Poor durability of concrete is a major cause of problems in modern building and civil engineering structures in all countries: the annual cost of investigating and repairing deteriorating reinforced concrete structures runs into many millions of pounds. This book explains the fundamentals of the corrosion of steel in concrete. It is comprehensive and provides a basis for the practising engineer to design concrete structures which avoid the problem using modern concepts and specifications. A limited discussion of corrosion measurement and repairs is also provided.
Publisher: CRC Press
ISBN: 9780419225300
Category : Technology & Engineering
Languages : en
Pages : 214
Book Description
Poor durability of concrete is a major cause of problems in modern building and civil engineering structures in all countries: the annual cost of investigating and repairing deteriorating reinforced concrete structures runs into many millions of pounds. This book explains the fundamentals of the corrosion of steel in concrete. It is comprehensive and provides a basis for the practising engineer to design concrete structures which avoid the problem using modern concepts and specifications. A limited discussion of corrosion measurement and repairs is also provided.
Damage and Cracking of Concrete Structures
Author: Jacky Mazars
Publisher: John Wiley & Sons
ISBN: 1394185960
Category : Technology & Engineering
Languages : en
Pages : 308
Book Description
Understanding and managing damage and cracking in concrete is essential to ensuring the integrity and durability of civil engineering structures. Both theoretical and practical, this book presents a comprehensive approach to these problems by proposing models and numerical modeling strategies that are treated in a manner that is both simplified and efficient. It proposes a wide variety of applications that are derived from research programs and engineering cases. This book also addresses many situations, such as monotonic or cyclic behavior, seismic responses, a description of fast dynamic situations and effects due to the maturation of concrete at an early age in massive structures. Numerous detailed exercises are provided to help students to understand modeling and calculation techniques. Damage and Cracking of Concrete Structures is indeed intended for students, but also for engineers and researchers in the field of mechanics of materials and structures and, more generally, in civil engineering.
Publisher: John Wiley & Sons
ISBN: 1394185960
Category : Technology & Engineering
Languages : en
Pages : 308
Book Description
Understanding and managing damage and cracking in concrete is essential to ensuring the integrity and durability of civil engineering structures. Both theoretical and practical, this book presents a comprehensive approach to these problems by proposing models and numerical modeling strategies that are treated in a manner that is both simplified and efficient. It proposes a wide variety of applications that are derived from research programs and engineering cases. This book also addresses many situations, such as monotonic or cyclic behavior, seismic responses, a description of fast dynamic situations and effects due to the maturation of concrete at an early age in massive structures. Numerous detailed exercises are provided to help students to understand modeling and calculation techniques. Damage and Cracking of Concrete Structures is indeed intended for students, but also for engineers and researchers in the field of mechanics of materials and structures and, more generally, in civil engineering.
Thermal Cracking in Concrete at Early Ages
Author: R. Springenschmid
Publisher: CRC Press
ISBN: 9780419187103
Category : Architecture
Languages : en
Pages : 500
Book Description
Restraint and intrinsic stresses in concrete at early ages are vitally important for concrete structures which must remain free of water-permeable cracks, such as water-retaining structures, tunnel linings, locks and dams. The development of hydration heat, stiffness and strength, also the degree of restraint and, especially for high-strength concrete, non-thermal effects, are decisive for sensitivity to cracking. Determining thses stresses in the laboratory and in construction components has led to a clearer understanding of how they develop and how to optimize mix design, temperature and curing conditions. New testing equipment has enabled the effects of all the important parameters to be qualified and more reliable models for predictiong restraint stresses to be developed. Thermal Cracking in Conrete at Early Ages contains 56 contributions by leading international specialists presented at the RILEM Symposium held in October 1994 at the Technical University of Munich. It will be valuable for construction and site engineers, concrete technologists and scientists.
Publisher: CRC Press
ISBN: 9780419187103
Category : Architecture
Languages : en
Pages : 500
Book Description
Restraint and intrinsic stresses in concrete at early ages are vitally important for concrete structures which must remain free of water-permeable cracks, such as water-retaining structures, tunnel linings, locks and dams. The development of hydration heat, stiffness and strength, also the degree of restraint and, especially for high-strength concrete, non-thermal effects, are decisive for sensitivity to cracking. Determining thses stresses in the laboratory and in construction components has led to a clearer understanding of how they develop and how to optimize mix design, temperature and curing conditions. New testing equipment has enabled the effects of all the important parameters to be qualified and more reliable models for predictiong restraint stresses to be developed. Thermal Cracking in Conrete at Early Ages contains 56 contributions by leading international specialists presented at the RILEM Symposium held in October 1994 at the Technical University of Munich. It will be valuable for construction and site engineers, concrete technologists and scientists.
Control of Cracking in Reinforced Concrete Structures
Author: Francis Barre
Publisher: John Wiley & Sons
ISBN: 1786300524
Category : Technology & Engineering
Languages : en
Pages : 256
Book Description
This book presents new guidelines for the control of cracking in massive reinforced and prestressed concrete structures. Understanding this behavior during construction allows engineers to ensure properties such as durability, reliability, and water- and air-tightness throughout a structure’s lifetime. Based on the findings of the French national CEOS.fr project, the authors extend existing engineering standards and codes to advance the measurement and prediction of cracking patterns. Various behaviors of concrete under load are explored within the chapters of the book. These include cracking of ties, beams and in walls, and the simulation and evaluation of cracking, shrinkage and creep. The authors propose new engineering rules for crack width and space assessment of cracking patterns, and provide recommendations for measurement devices and protocols. Intended as a reference for design and civil engineers working on construction projects, as well as to aid further work in the research community, applied examples are provided at the end of each chapter in the form of expanded measurement methods, calculations and commentary on models.
Publisher: John Wiley & Sons
ISBN: 1786300524
Category : Technology & Engineering
Languages : en
Pages : 256
Book Description
This book presents new guidelines for the control of cracking in massive reinforced and prestressed concrete structures. Understanding this behavior during construction allows engineers to ensure properties such as durability, reliability, and water- and air-tightness throughout a structure’s lifetime. Based on the findings of the French national CEOS.fr project, the authors extend existing engineering standards and codes to advance the measurement and prediction of cracking patterns. Various behaviors of concrete under load are explored within the chapters of the book. These include cracking of ties, beams and in walls, and the simulation and evaluation of cracking, shrinkage and creep. The authors propose new engineering rules for crack width and space assessment of cracking patterns, and provide recommendations for measurement devices and protocols. Intended as a reference for design and civil engineers working on construction projects, as well as to aid further work in the research community, applied examples are provided at the end of each chapter in the form of expanded measurement methods, calculations and commentary on models.
Fracture Mechanics of Concrete
Author: Surendra P. Shah
Publisher: John Wiley & Sons
ISBN: 9780471303114
Category : Technology & Engineering
Languages : en
Pages : 588
Book Description
FRACTURE MECHANICS OF CONCRETE AND ROCK This book offers engineers a unique opportunity to learn, frominternationally recognized leaders in their field, about the latesttheoretical advances in fracture mechanics in concrete, reinforcedconcrete structures, and rock. At the same time, it functions as asuperb, graduate-level introduction to fracture mechanics conceptsand analytical techniques. Reviews, in depth, the basic theory behind fracture mechanics * Covers the application of fracture mechanics to compressionfailure, creep, fatigue, torsion, and other advanced topics * Extremely well researched, applies experimental evidence ofdamage to a wide range of design cases * Supplies all relevant formulas for stress intensity * Covers state-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Describes nonlinear fracture mechanics (NLFM) and the latestRILEM modeling techniques for testing nonlinear quasi-brittlematerials * And much more Over the past few years, researchers employing techniques borrowedfrom fracture mechanics have made many groundbreaking discoveriesconcerning the causes and effects of cracking, damage, andfractures of plain and reinforced concrete structures and rock.This, in turn, has resulted in the further development andrefinement of fracture mechanics concepts and tools. Yet, despitethe field's growth and the growing conviction that fracturemechanics is indispensable to an understanding of material andstructural failure, there continues to be a surprising shortage oftextbooks and professional references on the subject. Written by two of the foremost names in the field, FractureMechanics of Concrete fills that gap. The most comprehensive bookever written on the subject, it consolidates the latest theoreticalresearch from around the world in a single reference that can beused by students and professionals alike. Fracture Mechanics of Concrete is divided into two sections. In thefirst, the authors lay the necessary groundwork with an in-depthreview of fundamental principles. In the second section, theauthors vividly demonstrate how fracture mechanics has beensuccessfully applied to failures occurring in a wide array ofdesign cases. Key topics covered in these sections include: * State-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Nonlinear fracture mechanics (NLFM) and the latest RILEM modelingtechniques for testing nonlinear quasi-brittle materials * The use of R-Curves to describe cracking and fracture inquasi-brittle materials * The application of fracture mechanics to compression failure,creep, fatigue, torsion, and other advanced topics The most timely, comprehensive, and authoritative book on thesubject currently available, Fracture Mechanics of Concrete is botha complete instructional tool for academics and students instructural and geotechnical engineering courses, and anindispensable working resource for practicing engineers.
Publisher: John Wiley & Sons
ISBN: 9780471303114
Category : Technology & Engineering
Languages : en
Pages : 588
Book Description
FRACTURE MECHANICS OF CONCRETE AND ROCK This book offers engineers a unique opportunity to learn, frominternationally recognized leaders in their field, about the latesttheoretical advances in fracture mechanics in concrete, reinforcedconcrete structures, and rock. At the same time, it functions as asuperb, graduate-level introduction to fracture mechanics conceptsand analytical techniques. Reviews, in depth, the basic theory behind fracture mechanics * Covers the application of fracture mechanics to compressionfailure, creep, fatigue, torsion, and other advanced topics * Extremely well researched, applies experimental evidence ofdamage to a wide range of design cases * Supplies all relevant formulas for stress intensity * Covers state-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Describes nonlinear fracture mechanics (NLFM) and the latestRILEM modeling techniques for testing nonlinear quasi-brittlematerials * And much more Over the past few years, researchers employing techniques borrowedfrom fracture mechanics have made many groundbreaking discoveriesconcerning the causes and effects of cracking, damage, andfractures of plain and reinforced concrete structures and rock.This, in turn, has resulted in the further development andrefinement of fracture mechanics concepts and tools. Yet, despitethe field's growth and the growing conviction that fracturemechanics is indispensable to an understanding of material andstructural failure, there continues to be a surprising shortage oftextbooks and professional references on the subject. Written by two of the foremost names in the field, FractureMechanics of Concrete fills that gap. The most comprehensive bookever written on the subject, it consolidates the latest theoreticalresearch from around the world in a single reference that can beused by students and professionals alike. Fracture Mechanics of Concrete is divided into two sections. In thefirst, the authors lay the necessary groundwork with an in-depthreview of fundamental principles. In the second section, theauthors vividly demonstrate how fracture mechanics has beensuccessfully applied to failures occurring in a wide array ofdesign cases. Key topics covered in these sections include: * State-of-the-art linear elastic fracture mechanics (LEFM)techniques for analyzing deformations and cracking * Nonlinear fracture mechanics (NLFM) and the latest RILEM modelingtechniques for testing nonlinear quasi-brittle materials * The use of R-Curves to describe cracking and fracture inquasi-brittle materials * The application of fracture mechanics to compression failure,creep, fatigue, torsion, and other advanced topics The most timely, comprehensive, and authoritative book on thesubject currently available, Fracture Mechanics of Concrete is botha complete instructional tool for academics and students instructural and geotechnical engineering courses, and anindispensable working resource for practicing engineers.
Corrosion of Steel in Concrete Structures
Author: Amir Poursaee
Publisher: Woodhead Publishing
ISBN: 0323851320
Category : Technology & Engineering
Languages : en
Pages : 400
Book Description
Essential reading for researchers, practitioners, and engineers, this book covers not only all the important aspects in the field of corrosion of steel reinforced concrete but also discusses new topics and future trends. Theoretical concepts of corrosion of steel in concrete structures, the variety of reinforcing materials and concrete, including stainless steel and galvanized steel, measurements and evaluations, such as electrochemical techniques and acoustic emission, protection and maintenance methods, and modelling, latest developments, and future trends in the field are discussed. - Comprehensive coverage of the corrosion of steel bars in concrete, investigating the range of reinforcing materials, and types of concrete - Introduces the latest measuring methods, data collection, and advanced modeling techniques - Second edition covers a range of new, emerging topics such as the concept of chloride threshold value, concrete permeability and chloride diffusion, the role of steel microstructure, and innovations in corrosion detection devices
Publisher: Woodhead Publishing
ISBN: 0323851320
Category : Technology & Engineering
Languages : en
Pages : 400
Book Description
Essential reading for researchers, practitioners, and engineers, this book covers not only all the important aspects in the field of corrosion of steel reinforced concrete but also discusses new topics and future trends. Theoretical concepts of corrosion of steel in concrete structures, the variety of reinforcing materials and concrete, including stainless steel and galvanized steel, measurements and evaluations, such as electrochemical techniques and acoustic emission, protection and maintenance methods, and modelling, latest developments, and future trends in the field are discussed. - Comprehensive coverage of the corrosion of steel bars in concrete, investigating the range of reinforcing materials, and types of concrete - Introduces the latest measuring methods, data collection, and advanced modeling techniques - Second edition covers a range of new, emerging topics such as the concept of chloride threshold value, concrete permeability and chloride diffusion, the role of steel microstructure, and innovations in corrosion detection devices