The Diagnosis of alkali-silica reaction

report of a working party.
  • 36 Pages
  • 4.42 MB
  • 7676 Downloads
  • English

British Cement Association , Slough
Alkali-aggregate reactions., Conc
ContributionsBritish Cement Association.
Classifications
LC ClassificationsTA440
The Physical Object
Pagination36p. ;
ID Numbers
Open LibraryOL22612073M
ISBN 100721013694

The alkali-silica reaction forms a gel that swells as it draws water from the surrounding cement on products from ASR have a great affinity for moisture.

In absorbing water, these gels can induce pressure, expansion, and cracking of the aggregate and surrounding reaction can be visualized as a two-step process:†† Size: KB.

Japanese approach to diagnosis Detailed guidance on the various stages of an investigation to establish whether or not a suspect structure has cracked as a consequence of alkali-silica reaction is given in a recent report of a working party which was set up by the Cement and Concrete Association.1 This chapter deals only with diagnosis.

Formerly known as the Cement The Diagnosis of alkali-silica reaction book Concrete Association, the British Cement Association is the trade and research organisation that represents the interests of the UK's cement industry. They have range of publications which include fact sheets, technical reports and good practice guides to support the use of concrete and cement in construction.

the diagnosis of alkali-silica reaction This report deals primarily with the diagnosis of the alkali silica reaction and the assessment of the role this reaction has. Alkali Silica Reaction - Diagnosis. Hobbs () recommends answering each of the following questions before pronouncing alkali-silica reaction as the original corrosion perpetrator.

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Is the map cracking or oriented cracking characteristic of that caused by ASR. Has expansion occurred. Measurements could be taken or the structure could be. Report on the Diagnosis, Prognosis, and Mitigation of Alkali-Silica Reaction (ASR) in Transportation Structures Alkali-aggregate reaction (AAR) is only one of the many factors that might be fully or partly responsible for the deterioration and premature loss in serviceability of concrete by:   This is a summary paper focused on the diagnosis of the alkali–aggregate reaction (AAR) in concrete in practice.

Rather than broadly attributing a crack to AAR, this paper provides guidance for a p Author: M.R. de Rooij. Two types of AAR reaction are currently recognized depending on the nature of the reactive mineral; alkali- silica reaction (ASR) involves various types of reactive silica (SiO.

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2) minerals and alkali-carbonate reaction (ACR) involves certain types of dolomitic rocks. Alkali–silica reaction (ASR)—performance testing: Influence of specimen pre-treatment, exposure conditions and prism size on concrete porosity, moisture state and transport properties Author links open overlay panel Jan Lindgård a Erik J.

Sellevold b Michael D.A. Thomas c Bård Pedersen d Harald Justnes a b Terje F. Rønning eCited by:   Alkali-Silica Reaction: Causes and Solutions Alkali-silica reactivity, better known as ASR, has been with us since the early s. To lessen ASR problems use low-alkali portland cement or incorporate pozzolans.

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The reaction mechanism consists of several successive steps: initial attack of OH − compounds on the SiO 2 at the aggregate–cement paste boundary; formation of silanol groups at the SiO 2 surface; formation of siloxane groups, and their polymerization; adsorption of alkaline and Ca 2+ ions.

The alkali–silica reaction, more commonly known as "concrete cancer", is a swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive non-crystalline silica found in many common aggregates, given sufficient moisture.

This reaction causes the expansion of the altered aggregate by the formation of a soluble and viscous gel of sodium silicate. This. Jones, Trevor N., and Poole, Alan B., “Alkali-Silica Many individuals and organizations within the cement and Reaction in Several U.

Concretes: The Effect of concrete industries have contributed to this first edition of Temperature and Humidity on Expansion, and the Diagnosis and Control of Alkali-Aggregate Reactions in Significance of.

History, the reaction, cracking and pessimum behaviour; effect of mix proportion and constituents upon expansion; effect of applied stress upon the mechanical properties; structural effects and implications and repair; diagnosis; GGBS, PFA and silica fume; testing aggregates and cement aggregate combinations for their reactivity; minimizing the risk of expansion in new construction.

This report describes alkali-silica reaction (ASR) degradation mechanisms and factors influencing the ASR. A fully coupled thermo-hydro-mechanical-chemical model developed by Saouma and Perotti by taking into consideration the effects of stress on the reaction kinetics and anisotropic volumetric expansion is presented in this report.

Alkali Silica Reactions By Karthik Obla, Ph.D., P.E. Director of Research and Materials Engineering, NRMCA Reactivity Level Aggregate Expansion, C1-year % Equal to or greater than Less than Very Highly Reactive (VHR) - Highly Reactive (HR) Moderately Reactive (MR) Significant research and efforts have gone toward.

Description The Diagnosis of alkali-silica reaction EPUB

The alkali–silica reaction has received much attention and the first to be recognized involves a reaction between the OH-ion associated with the alkalis (Na 2 O and K 2 O) from the cement and other sources, with certain siliceous constituents [P NO ] that can be present in the aggregate.

This phenomenon was referred to as an alkali–aggregate reaction but is more properly designated as. Summary. 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 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.

AAR has been studied since the mid s after the discovery of alkali-silica reaction (ASR) by Thomas Stanton of the California Division of Highways. A conference series devoted to understanding reaction mechanisms, testing methods, prediction, diagnosis and repair has been active since with a total of 14 conferneces held to date.

The alkali–silica reaction (ASR) is the most general form of AAR which only rarely causes degradation in Finland. The pool at Tampere Swimming Centre was only the third such case in the country.

Diagnosing Alkali-Silica Reaction. Diagnosis of ASR typically begins with visual inspection prompted by the presence of characteristic surface features, such as macro-cracking, gel exudation and staining along the cracks, closing of expansion joints, and even localized crushing (blowups) in pavements.

The Diagnosis of Alkali-Silica Reaction—Report of a Working Party. British Cement Association, Slough, British Cement Association, Slough, Google ScholarCited by: 1.

A method using concentrated aqueous solutions of sodium cobaltinitrite and rhodamine B is described which can be used to identify concrete that contains gels formed by the alkali-silica reaction (ASR). These solutions present little health or environmental risk, are readily applied, and rapidly discriminate between two chemically distinct gels; K-rich, Na--K--Ca--Si gels are identified by Cited by: 3.

Information on the development of alkali-silica reaction (ASR) damage in the UK, the chemical process of ASR, and the diagnosis and assessment of expansion and cracking on concrete.

Data derived from research presented at the 8th International alkali-aggregate reaction conference held in Kyoto inand additional field experience of the. 12 Practices to Mitigate Alkali-Silica Reaction (ASR) Affected Pavements at Airports As explained by Thomas and colleagues (a), ASR is initiated by a reaction between the hydroxyl ions in the pore solution and certain types of silica in the aggregate.

4. Alkali-Aggregate Reactions 5. Principles of Minimising the Risk of ASR 6. Assessment of Aggregates 7. Estimation of Alkali Contributed by Concrete Constitutents Apendix A: Glossary Apendix B: Chemistry of the Alkali Silica Reaction Apendix C: Sample Calculations Apendix D: Results of Testing Aggregates Using ASTM C Publication Details Report on the Diagnosis, Prognosis, and Mitigation of Alkali- Silica Reaction (ASR) in Transportation Structures.

Primary Topic: Materials-Concrete. Description: Alkali–aggregate reaction (AAR) is only one of the many factors that might be fully or partly responsible for the deterioration and premature loss in serviceability of concrete infrastructure.

Alkali-silica reaction (ASR) is a leading cause of premature concrete deterioration, resulting in cracks that develop in concrete structures.

ASR is a slow chemical reaction, taking years to manifest. Therefore, ASTM currently has several widely used laboratory tests to more rapidlyCited by: 1. 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 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 Cited by: 9.

The alkali-silica reaction though not true is described as a concrete cancer. A human cancer, if untreated is terminal, whereas the alkali-silica reaction and the expansion it induces, if untreated, eventually stops.

No concreted structure or part of a concrete structure any where in the world has collapsed due to alkali-silica reaction alone. In this study, the suitability of the threshold alkali level, TAL, the kinetic parameter, In k, and the microstructural disorder coefficient, Cd, of the aggregates, taken as alkali-silica reactivity criteria, was assessed using different typologies of Italian natural ASR-susceptible aggregates of known field performance.

The TAL, In k, and Cd were determined using a modified version of the Cited by: alkali-silica reaction (ASR). (Martinez, ). This usually occurs between the highly alkaline Portland cement and the various siliceous substances contained in the aggregate. (Mishra, ).

This reaction produces a hygroscopic gel, which absorbs water and swells, causing cracking to occur as tension builds in the concrete structure.