Alkali Aggregate Reaction In Concrete Roads And Bridges

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.

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.

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.

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.

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.

Aggregates containing certain constituents can react with alkali hydroxides in concrete. The reactivity is potentially harmful only when it produces significant expansion. This alkali-aggregate reactivity (AAR) has two forms--alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR, sometimes called alkali-carbonate rock reaction, or ACRR). ASR is of more concern than ACR because the occurrence of aggregates containing reactive silica minerals is more common. Alkali-reactive carbonate aggregates have a specific composition that is not very common. Alkali-silica reactivity has been recognized as a potential source of distress in concrete since the later 1930s. Even though potentially reactive aggregates exist throughout North America, ASR distress in structural concrete is not common. There are a number of reasons for this: 1. Most aggregates are chemically stable in hydraulic-cement concrete 2. Aggregates with good service records are abundant in many areas 3. The concrete in service is dry enough to inhibit ASR 4. The use of certain pozzolans or slags controls ASR 5. In many concrete mixtures, the alkali content of the concrete is low enough to control harmful ASR 6. Some forms of ASR do not produce significant deleterious expansion To reduce ASR potential requires understanding the ASR mechanism; properly using tests to identify potentially reactive aggregates; and, if needed, taking steps to minimize the potential for expansion and related cracking. Alkali-carbonate reaction in concrete was not documented until 1957. Although ACR is much less common, this report also briefly reviews the mechanism, visual distress symptoms, identification tests, and control measures.

Lea's Chemistry of Cement and Concrete, Fifth Edition, examines the suitability and durability of different types of cements and concretes, their manufacturing techniques and the role that aggregates and additives play in achieving concrete's full potential of delivering a high-quality, long-lasting, competitive and sustainable product. Provides a 60% revision over the fourth edition last published in 2004 Includes updated chapters that represent the latest technological advances in the industry, including, but not exclusive to the production of low-energy cements, cement admixtures and concrete aggregates Presents expanded coverage of the suitability and durability of materials aggregates and additives