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Author by : Graham West
Languange Used : en
Release Date : 1996
Publisher by : Thomas Telford
ISBN : 0727720694
This book provides a sound understanding of the alkali-aggregate reaction and how it affects the design, construction and maintenance of concrete roads and bridges. It draws on examples from the UK and around the world to relate experience of damage caused by this reaction and how the problems have been investigated and treated....
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Author by : Ahmad Shayan
Languange Used : en
Release Date : 1994
Publisher by :
ISBN : OCLC:223725364
Alkali-aggregate reaction (AAR) in concrete is potentially a deleterious reaction which can lead to premature deterioration of major structures such as concrete bridges and roads. Severe cracking of the affected structure exposes the interior of the concrete to aggressive agents, leading to further deterioration. Once the structure is built with reactive ingredients, an ongoing expansive reaction takes place which causes continual cracking of the structure and widening of the existing cracks. The decision to repair such structures should be made carefully, based on the residual expansion of the concrete, the environment of the affected structure, the overall condition of the structure and its safety, and cost-effectiveness of the repair. These considerations should form a part of the management strategy of the bridge network. Measures to prevent AAR damage to concrete roads and bridge structure will also be outlined....
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Author by : David Stark
Languange Used : en
Release Date : 1991
Publisher by :
ISBN : UCBK:C101234074
This handbook is designed to help highway engineers and bridge inspectors spot and fix this very damaging and difficult-to-detect problem, namely, alkali-silica reactivity (ASR). The 49-page handbook provides for the field identification of ASR in portland cement concrete structures, such as highway pavements and bridges. ASR occurs when silica or silicates in aggregates react with alkali in the cement to form a gel-like substance which absorbs water and eventually cracks the concrete. Some areas of the country are more susceptible to this than others. Accurate detection of ASR is the key to choosing the best rehabilitation strategy. The proper diagnosis and assessment of the problem is covered....
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Author by : National Research Council (U.S.). Transportation Research Board
Languange Used : en
Release Date : 1999
Publisher by :
ISBN : UCSD:31822034449538
...
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Author by : National Research Council (U.S.). Highway Research Board
Languange Used : en
Release Date : 1958
Publisher by :
ISBN : ERDC:35925002007844
Covers a discussion of the problem of deterioration of certain concretes caused by an expansive reaction between the alkalies in the cement and certain constituents of the aggregate. Presented in 3 parts. One dealing with field experiences. A second with the laboratory tests and a third with theoretical considerations and present research....
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Author by : Ian Sims
Languange Used : en
Release Date : 2017-08-01
Publisher by : CRC Press
ISBN : 9781317484417
Alkali-Aggregate Reaction in Concrete: A World Review is unique in providing authoritative and up to date expert information on the causes and effects of Alkali-Aggregate Reaction (AAR) in concrete structures worldwide. In 1992 a first edition entitled The Alkali-Silica Reaction in Concrete, edited by Professor Narayan Swamy, was published in a first attempt to cover this concrete problem from a global perspective, but the coverage was incomplete. This completely new edition offers a fully updated and more universal coverage of the world situation concerning AAR and includes a wealth of new evidence and research information that has accumulated in the intervening years. Although there are various textbooks offering readers sections that deal with AAR deterioration and damage to concrete, no other single book brings together the views of recognised international experts in the field, and the wealth of scattered research information that is available. It provides a ‘state of the art’ review and deals authoritatively with the mechanisms of AAR, its diagnosis and how to treat concrete affected by AAR. It is illustrated by numerous actual examples from around the world, and comprises specialist contributions provided by senior engineers and scientists from many parts of the world. The book is divided into two distinct but complementary parts. The first five chapters deal with the most recent findings concerning the mechanisms involved in the reaction, methods concerning its diagnosis, testing and evaluation, together with an appraisal of current methods used in its avoidance and in the remediation of affected concrete structures. The second part is divided into eleven chapters covering each region of the world in turn. These chapters have been written by experts with specialist knowledge of AAR in the countries involved and include an authoritative appraisal of the problem and its solution as it affects concrete structures in the region. Such an authoritative compilation of information on AAR has not been attempted previously on this scale and this work is therefore an essential source for practising and research civil engineers, consultant engineers and materials scientists, as well as aggregate and cement producers, designers and concrete suppliers, especially regarding projects outside their own region....
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Author by : Reza Akhavan
Languange Used : en
Release Date : 1989
Publisher by :
ISBN : UCBK:C101292962
Colorado frequently experiences pavement deterioration due to reactive aggregates. This study examined whether alkali-silica reactivity was also causing damage to bridge structures. A number of bridges were inspected and samples were extracted from five and subjected to a petrographer's analysis. Three of the five samples showed conclusive evidence of alkali-silica reactivity. Evidence was not conclusive in two other samples (A)....
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Author by : Edward F. Duke
Languange Used : en
Release Date : 1998
Publisher by :
ISBN : OCLC:56029949
This report presents the results of a study to evaluate the extent of alkali-silica (ASR) and alkali-carbonate (ACR) reactions in pavement ans structural concrete from selected sites in South Dakota, and to assess the role of these reactions in premature deterioration of the concrete. The main focus of the report is a petrographic examination of samples from the Platte-Winner Bridge. It was determined that ACR is widespread in concrete cores from failed pier caps 16-17 of the bridge. ACR is known to contribute to premature deterioration of concrete containing dolomite (CaMg[CO3]2) as aggregate, although the exact mechanisms leading to deterioration are not fully understood. Examination of the concrete cores using optical microscopy and scanning electron microscopy indicates two mechanisms by which ACR may have contributed to deterioration of this structure: 1) Secondary porosity is observed within aggregate particles where dolomite is converted to calcite and brucite. 2) Microfractures observed in aggregate appear to have originated near the aggregate rim and propagated outward into the paste. Both effects could be explained by small, local volume contraction associated with ACR. Once secondary porosity and permeability are established on a microscopic scale, deterioration by freezing and thawing or other mechanisms may accelerate the process of concrete deterioration. It was also determined that the bridge samples contained unacceptably low levels of entrained air, and this was likely a major factor leading to failure. The results of the study of the Platte-Winner Bridge, in conjunction with results from concrete pavement samples from eastern South Dakota, indicate that dolomite should be considered a highly deleterious component of both coarse and fine sand aggregate sources, and that its application should be minimized....
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Author by : R N Swamy
Languange Used : en
Release Date : 1991-09-01
Publisher by : CRC Press
ISBN : 9780203036631
This book reviews the fundamental causes and spectrum effects of ASR. It considers he advances that have been made in our understanding of this problem throughout the world....
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Author by : Ian Sims
Languange Used : en
Release Date : 2017-08-01
Publisher by : CRC Press
ISBN : 9781317484424
Alkali-Aggregate Reaction in Concrete: A World Review is unique in providing authoritative and up to date expert information on the causes and effects of Alkali-Aggregate Reaction (AAR) in concrete structures worldwide. In 1992 a first edition entitled The Alkali-Silica Reaction in Concrete, edited by Professor Narayan Swamy, was published in a first attempt to cover this concrete problem from a global perspective, but the coverage was incomplete. This completely new edition offers a fully updated and more universal coverage of the world situation concerning AAR and includes a wealth of new evidence and research information that has accumulated in the intervening years. Although there are various textbooks offering readers sections that deal with AAR deterioration and damage to concrete, no other single book brings together the views of recognised international experts in the field, and the wealth of scattered research information that is available. It provides a ‘state of the art’ review and deals authoritatively with the mechanisms of AAR, its diagnosis and how to treat concrete affected by AAR. It is illustrated by numerous actual examples from around the world, and comprises specialist contributions provided by senior engineers and scientists from many parts of the world. The book is divided into two distinct but complementary parts. The first five chapters deal with the most recent findings concerning the mechanisms involved in the reaction, methods concerning its diagnosis, testing and evaluation, together with an appraisal of current methods used in its avoidance and in the remediation of affected concrete structures. The second part is divided into eleven chapters covering each region of the world in turn. These chapters have been written by experts with specialist knowledge of AAR in the countries involved and include an authoritative appraisal of the problem and its solution as it affects concrete structures in the region. Such an authoritative compilation of information on AAR has not been attempted previously on this scale and this work is therefore an essential source for practising and research civil engineers, consultant engineers and materials scientists, as well as aggregate and cement producers, designers and concrete suppliers, especially regarding projects outside their own region....