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Author: Norbert J. Delatte Publisher: ISBN: Category : Bridges Languages : en Pages : 148
Book Description
Early age cracking of bridge decks is a national problem, and may substantially reduce service lives and increase maintenance costs. Cracking occurs when the tensile stress exceeds the tensile strength of the concrete. This is a time-dependent phenomenon, since both the stress and strength change at early ages. Moisture loss increases stress (with increasing shrinkage) and impairs strength gain. Internal curing is one method that has been suggested to reduce early age bridge deck cracking, particularly of concretes with low water to cementitious materials (w/cm) ratios. Many state highway agencies have implemented high performance concrete (HPC) for bridge decks. The low permeability of HPC is used to protect reinforcing steel and prevent corrosion. However, if the concrete cracks, then the protection may be greatly diminished. Transverse cracks due to concrete shrinkage allow water and corrosive chemicals to quickly reach the reinforcing steel causing corrosion and shortening the lifespan of the bridge deck. Reducing shrinkage cracking has been the focus of recent research into mitigation strategies. One unintended consequence of the use of high performance concrete may be early-age cracking. Field studies have shown that, in some cases, high performance concrete bridge decks have cracked less than a year after placement. The use of internal curing to reduce autogenous shrinkage was investigated in this study. One method of internal curing was through the use of coarse aggregates with high absorption capacities. Another method discussed is the use of a partial replacement of the fine aggregate with a structural lightweight aggregate with a very high absorption capacity. Bridge deck cracking is also affected by the nominal maximum size coarse aggregate. The effect on shrinkage with increasing size is discussed. ODOT's District 12, located in Northeastern Ohio, found in an investigation of 116 HPC bridge decks placed between 1994 and 2001 that bridges with little or no cracking used coarse aggregate with an absorption> 1 %, while 75 % of bridges with unacceptable cracking used coarse aggregate with absorption 1 %. This report discusses the laboratory investigation of the field results to determine the better ways to prevent bridge deck cracking-- internal curing or paste reduction by using an aggregate blend. The laboratory investigation found that the strongest effect on cracking was due to the replacement of a small maximum size coarse aggregate with an optimized coarse aggregate gradation. Increasing the coarse aggregate absorption level from
Author: Norbert J. Delatte Publisher: ISBN: Category : Bridges Languages : en Pages : 148
Book Description
Early age cracking of bridge decks is a national problem, and may substantially reduce service lives and increase maintenance costs. Cracking occurs when the tensile stress exceeds the tensile strength of the concrete. This is a time-dependent phenomenon, since both the stress and strength change at early ages. Moisture loss increases stress (with increasing shrinkage) and impairs strength gain. Internal curing is one method that has been suggested to reduce early age bridge deck cracking, particularly of concretes with low water to cementitious materials (w/cm) ratios. Many state highway agencies have implemented high performance concrete (HPC) for bridge decks. The low permeability of HPC is used to protect reinforcing steel and prevent corrosion. However, if the concrete cracks, then the protection may be greatly diminished. Transverse cracks due to concrete shrinkage allow water and corrosive chemicals to quickly reach the reinforcing steel causing corrosion and shortening the lifespan of the bridge deck. Reducing shrinkage cracking has been the focus of recent research into mitigation strategies. One unintended consequence of the use of high performance concrete may be early-age cracking. Field studies have shown that, in some cases, high performance concrete bridge decks have cracked less than a year after placement. The use of internal curing to reduce autogenous shrinkage was investigated in this study. One method of internal curing was through the use of coarse aggregates with high absorption capacities. Another method discussed is the use of a partial replacement of the fine aggregate with a structural lightweight aggregate with a very high absorption capacity. Bridge deck cracking is also affected by the nominal maximum size coarse aggregate. The effect on shrinkage with increasing size is discussed. ODOT's District 12, located in Northeastern Ohio, found in an investigation of 116 HPC bridge decks placed between 1994 and 2001 that bridges with little or no cracking used coarse aggregate with an absorption> 1 %, while 75 % of bridges with unacceptable cracking used coarse aggregate with absorption 1 %. This report discusses the laboratory investigation of the field results to determine the better ways to prevent bridge deck cracking-- internal curing or paste reduction by using an aggregate blend. The laboratory investigation found that the strongest effect on cracking was due to the replacement of a small maximum size coarse aggregate with an optimized coarse aggregate gradation. Increasing the coarse aggregate absorption level from
Author: Tada-aki Tanabe Publisher: CRC Press ISBN: 0203882954 Category : Technology & Engineering Languages : en Pages : 1552
Book Description
CREEP, SHRINKAGE AND DURABILITY MECHANICS OF CONCRETE AND CONCRETE STRUCTURES contains the keynote lectures, technical reports and contributed papers presented at the Eighth International Conference on Creep, Shrinkage and Durability of Concrete and Concrete Structures (CONCREEP8, Ise-shima, Japan, 30 September - 2 October 2008). The topics covered
Author: Peter C. Taylor Publisher: CRC Press ISBN: 0203866134 Category : Technology & Engineering Languages : en Pages : 214
Book Description
Curing is one of those activities that every civil engineer and construction worker has heard of, but in reality does not worry about much. In practice, curing is often low on the list of priorities on the construction site, particularly when budgets and timelines are under pressure. Yet the increasing demands being placed on concrete mixtures also
Author: Roberto J. Torrent Publisher: CRC Press ISBN: 0429012918 Category : Technology & Engineering Languages : en Pages : 536
Book Description
Durability and service life design of concrete constructions have considerable socio-economic and environmental consequences, in which the permeability of concrete to aggressive intruders plays a vital role. Concrete Permeability and Durability Performance provides deep insight into the permeability of concrete, moving from theory to practice, and presents over 20 real cases, such as Tokyo’s Museum of Western Art, Port of Miami Tunnel and Hong Kong-Zhuhai-Macao sea-link, including field tests in the Antarctic and Atacama Desert. It stresses the importance of site testing for a realistic durability assessment and details the "Torrent Method" for non-destructive measurement of air-permeability. It also delivers answers for some vexing questions: Should the coefficient of permeability be expressed in m2 or m/s? How to get a "mean" pore radius of concrete from gas-permeability tests? Why should permeability preferably be measured on site? How can service life of reinforced concrete structures be predicted by site testing of gas-permeability and cover thickness? Practitioners will find stimulating examples on how to predict the coming service life of new structures and the remaining life of existing structures, based on site testing of air-permeability and cover thickness. Researchers will value theoretical principles, testing methods, as well as how test results reflect the influence of concrete mix composition and processing.
Author: National Research Council (U.S.). Highway Research Board. Western Summer Meeting Publisher: Transportation Research Board National Research ISBN: Category : Technology & Engineering Languages : en Pages : 254
Book Description
This issue of HRB Special Report contains the papers presented at the Western Summer Meeting, held in Sacramento, California and is organized into three categories. The first group are papers that attempt to identify some of the factors contributing to the deterioration of concrete bridge decks. The second group addresses the general subject of evaluating pavement serviceability and performance. The third group investigates the design and construction of overlays and surface treatments for pavement rehabilitation.
Author: Hiroshi Yokota Publisher: CRC Press ISBN: 1000173755 Category : Technology & Engineering Languages : en Pages : 926
Book Description
Bridge Maintenance, Safety, Management, Life-Cycle Sustainability and Innovations contains lectures and papers presented at the Tenth International Conference on Bridge Maintenance, Safety and Management (IABMAS 2020), held in Sapporo, Hokkaido, Japan, April 11–15, 2021. This volume consists of a book of extended abstracts and a USB card containing the full papers of 571 contributions presented at IABMAS 2020, including the T.Y. Lin Lecture, 9 Keynote Lectures, and 561 technical papers from 40 countries. The contributions presented at IABMAS 2020 deal with the state of the art as well as emerging concepts and innovative applications related to the main aspects of maintenance, safety, management, life-cycle sustainability and technological innovations of bridges. Major topics include: advanced bridge design, construction and maintenance approaches, safety, reliability and risk evaluation, life-cycle management, life-cycle sustainability, standardization, analytical models, bridge management systems, service life prediction, maintenance and management strategies, structural health monitoring, non-destructive testing and field testing, safety, resilience, robustness and redundancy, durability enhancement, repair and rehabilitation, fatigue and corrosion, extreme loads, and application of information and computer technology and artificial intelligence for bridges, among others. This volume provides both an up-to-date overview of the field of bridge engineering and significant contributions to the process of making more rational decisions on maintenance, safety, management, life-cycle sustainability and technological innovations 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 engineers, researchers, academics and students from all areas of bridge engineering.
Author: Geert De Schutter Publisher: CRC Press ISBN: 0203834445 Category : Technology & Engineering Languages : en Pages : 209
Book Description
Serious degradation mechanisms can severely reduce the service life of concrete structures: steel reinforcement can corrode, cement matrix can be attacked, and even aggregates can show detrimental processes. Therefore, it is important to understand how damage can occur to concrete structures and to appreciate the timing of the actions leading to damage. Damage to Concrete Structures summarizes the state-of-the-art information on the degradation of concrete structures, and gives a clear and comprehensive overview of what can go wrong. Offering a logical flow, the chapters are ordered according to the chronological timing of the actions leading to concrete damage. The author explains the different actions or mechanisms in a fundamental manner, without too many physical or chemical details, to provide greater clarity and readability. The book describes the different causes of damage to concrete, including inappropriate design, errors during execution, mechanisms occurring during hardening of concrete, and actions or degradation mechanisms during service life (hardened concrete). The degradation mechanisms are illustrated with numerous real-world examples and many drawings and photographs taken of actual structures. Written as a textbook for students as well as a reference for professionals, this easy-to-comprehend book gives readers a deeper understanding of the damage that can occur to concrete during the construction process and service.
Author: Francois de Larrard Publisher: CRC Press ISBN: 9780419235002 Category : Architecture Languages : en Pages : 450
Book Description
The design of concrete mixes is becoming increasingly complex, with the addition of new materials in the compounds, such as organic admixtures, fibres and supplementary cementitious materials. Moreover, the list of properties which concretes are required to possess for certain applications has increased, and interest is developing in rheology, durability, deformability and whole-life behaviour. This book presents a number of simple models for the understanding of a concrete system, and provides the techniques for developing more sophisticated models for the practical design of concrete mixes.
Author: H. Hilsdorf Publisher: CRC Press ISBN: 0203626672 Category : Architecture Languages : en Pages : 226
Book Description
This is a state-of-the-art report prepared by RILEM Technical Committee 116-PCD and is an authoritative, international review of the subject and is an essential reference source for engineers and technologists. Performance Criteria for Concrete Durability explains key aspects of concrete durability, and the relationships between transport mechanisms and concrete durability characteristics. It reviews test methods for measuring permeability in the laboratory and on site, and discusses the many factors which influence the durability of concrete to carbonation, chlorides, abrasion etc.
Author: Norbert J. Delatte
Author: Norbert J. Delatte
Author: Tada-aki Tanabe
Author: Peter C. Taylor
Author: Roberto J. Torrent
Author: National Research Council (U.S.). Highway Research Board. Western Summer Meeting
Author: Zhigang Zhang
Author: Hiroshi Yokota
Author: Geert De Schutter
Author: Francois de Larrard
Author: H. Hilsdorf