AlkaliAggregate Reaction of Concrete Structures

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Alkali-Aggregate Reaction of Concrete Structures

2013-6-13  Alkali aggregate reaction (AAR) occurs when the alkali in concrete reacts with some deleterious minerals in the aggregate when there is sufficient moisture, causing expansion and cracking of the concrete. AAR was first observed in Hong Kong in 1991. A review of international practice led the promulgation of Works Bureau Technical Circular

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Alkali-Aggregate Reaction (AAR) of Concrete Structures

2013-6-13  alkali content of concrete, use of low alkali cement, include PFA, GGBS, etc. M2: Avoid the presence of a critical amount of reactive silica, e.g. identify non-reactive aggregate M3: reduce the access of moisture and maintain the concrete in a sufficiently dry state, e.g. use external cladding or tanking

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Alkali Aggregate Reaction in Concrete - Types, Causes, and ...

2019-7-16  Effects of Alkali-Aggregate Reaction. Loss of strength, stiffness, impermeability. Affects concrete durability and appearance. Premature failure of concrete structures. Consequently, life of concrete structure is declined. Maintenance cost is increased. Fig. 2: Affect of Alkali Aggregate Reaction

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Alkali-Aggregate Reaction (AAR) of Concrete Structures

Casting 1 day 2 days Percentage increase in weight ( % ) = Wn – W2 x 100 % W2 Where Wn is the weight at n days age. 1 week Percentage increase in length ( % ) = Ln –L2 x 100 % 2 weeks Li Where Ln is the length of prism with studs at n days age. 4 weeks ( Ln = Rn + calibrated length of reference bar). 13 weeks 26 weeks 52 weeks fCPT: RILEM ...

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219-ACS : Alkali Aggregate Reaction in concrete structures ...

The specific uses of these results will be in managing structures affected by alkali reactions, also in specifying, designing and proving concrete mixes for new structures on a project-specific basis. The economic impact will be large. Deterioration of concrete structures because of alkali reactions is an increasing problem worldwide.

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Effects of alkali–aggregate reaction on concrete and ...

2020-1-22  The effects of alkali–aggregate reaction (AAR) on concrete and structures start at the microstructural level, that is, at molecular and microscopic levels, such as the formation of reaction products in concrete and associated microcracking, which ultimately leads to macro-level effects such as visual cracking, differential movements, displacement and so on.

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ALKALI AGGREGATE REACTIONS (AAR) IN CONCRETE

2016-9-28  Alkali-aggregate reaction (ASR) in concrete is one of the least dealt with concrete degradation mechanism in Finland. It is a common belief that it does not occur due to the exceptional quality of Finland’s granitic rock. However, over 50 cases have been identified

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ALKALI AGGREGATE REACTION IN NUCLEAR CONCRETE

2017-6-9  Three main types of alkali aggregate reaction (AAR) have been identified depending on the aggregates: alkali silica reaction, alkali carbonate reaction (ACR) and alkali silicate reaction (ASLR) (Blight and Alexander 2011). ASR involves reactions between alkali pore solution in the concrete and certain forms of alkali-reactive silica.

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MODELLING OF ALKALI-AGGREGATE REACTION EFFECTS

2017-6-3  Modelling of Alkali-Aggregate Reaction Effects in Reinforced Concrete Structures Anca-Cristina Jurcut Master of Applied Sciences Graduate Department of Civil Engineering University of Toronto 2015 Abstract Significant research has been performed worldwide on alkali-aggregate reaction (AAR) since its first deleterious effects on concrete ...

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Analysis of concrete structures deteriorated by alkali ...

2017-8-29  of alkali-aggregate reaction in the studied pier. 2 Alkali-aggregate reaction The Brazilian standard NBR 15577-1 [2], defines the alkali-aggregate reaction (AAR) as: A chemical reaction between certain constituents present in certain types of aggregates and alkali components that are dissolved in the solution of concrete pores.

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Alkali Aggregate Reaction in Concrete - Types, Causes, and ...

Effects of Alkali-Aggregate Reaction. Loss of strength, stiffness, impermeability. Affects concrete durability and appearance. Premature failure of concrete structures. Consequently, life of concrete structure is declined. Maintenance cost is increased. Fig. 2: Affect of Alkali Aggregate Reaction

Get price

Effects of alkali–aggregate reaction on concrete and ...

2020-1-22  The effects of alkali–aggregate reaction (AAR) on concrete and structures start at the microstructural level, that is, at molecular and microscopic levels, such as the formation of reaction products in concrete and associated microcracking, which ultimately leads to macro-level effects such as visual cracking, differential movements, displacement and so on.

Get price

219-ACS : Alkali Aggregate Reaction in concrete structures ...

The specific uses of these results will be in managing structures affected by alkali reactions, also in specifying, designing and proving concrete mixes for new structures on a project-specific basis. The economic impact will be large. Deterioration of concrete structures because of alkali reactions is an increasing problem worldwide.

Get price

ALKALI AGGREGATE REACTION IN NUCLEAR CONCRETE

2017-6-9  ASR concrete and the other regular concrete. The walls were tested under lateral displacement excursions while simultaneously subjected to axial load simulating seismic loads. INTRODUCTION Alkali-Aggregate Reaction (AAR) problem is common in many structures such as bridges, roadways, airport runways, and nuclear power plants.

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ALKALI-AGGREGATE REACTION IN CONCRETE : A REVIEW

ALKALI-AGGREGATE REACTION IN CONCRETE : A REVIEW OF BASIC CONCEPTS AND ENGINEERING IMPLICATIONS. ... The management section includes the diagnosis of AAR in existing concrete structures, evaluation of potential for future distress due to AAR, and mitigation and repair approaches used on such structures. This is an introductory paper and sets ...

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Alkali-Aggregate Reaction in Concrete: A World Review

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 ...

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MODELLING OF ALKALI-AGGREGATE REACTION EFFECTS

2017-6-3  Modelling of Alkali-Aggregate Reaction Effects in Reinforced Concrete Structures Anca-Cristina Jurcut Master of Applied Sciences Graduate Department of Civil Engineering University of Toronto 2015 Abstract Significant research has been performed worldwide on alkali-aggregate reaction (AAR) since its first deleterious effects on concrete ...

Get price

Causes of Damage to Concrete-Alkali aggregate reaction ...

The repairing of concrete actively undergoing aggregate alkali reaction considered useless because the continues expansion of concrete will disrupt and damage the repaired portion. Structures undergoing active deterioration should be monitored for the rate of expansion and movement, and only the repairs necessary to maintain safe operation of ...

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MODELLING OF ALKALI-AGGREGATE REACTION IN

2020-11-6  MODELLING OF ALKALI-AGGREGATE REACTION IN CONCRETE PILE CAPS STRUCTURES Marco Juliani1*, Lucas Juliani1, Tiago Juliani1, Daniela David1, Liana Becocci1 1IEME BRASIL Engenharia Consultiva, São Paulo, SP, BRAZIL Abstract Many concrete reinforced structures throughout the world are suffering from deteriorations

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Predicting the incidence of alkali-aggregate reaction in ...

Alkali-aggregate reaction (AAR) is a prominent degradation mechanism of concrete structures, which results from the dissolution of reactive silicate aggregates and the associated formation of damaging, expansive AAR gels.

Get price

Alkali Aggregate Reaction in Concrete - Types, Causes, and ...

Effects of Alkali-Aggregate Reaction. Loss of strength, stiffness, impermeability. Affects concrete durability and appearance. Premature failure of concrete structures. Consequently, life of concrete structure is declined. Maintenance cost is increased. Fig. 2: Affect of Alkali Aggregate Reaction

Get price

Alkali-Aggregate Reaction in Concrete : A World Review ...

Alkali-Aggregate Reaction in Concrete 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 ...

Get price

ALKALI AGGREGATE REACTION IN NUCLEAR CONCRETE

2017-6-9  ASR concrete and the other regular concrete. The walls were tested under lateral displacement excursions while simultaneously subjected to axial load simulating seismic loads. INTRODUCTION Alkali-Aggregate Reaction (AAR) problem is common in many structures such as bridges, roadways, airport runways, and nuclear power plants.

Get price

Alkali-Aggregate Reaction in Concrete

2008-2-15  Testing of Australian Concrete Mixtures for Alkali-Silica Reaction Potential and Calibration with Field Performance of Structures Carse.A 247 Alkali-Aggregate Reaction Assessment in Kansas Clowers, K.A., Abou-Zeid, M.N 257 Evaluation of The Potential Alkali-Reactivity of Concrete Aggregates: Performance of Testing Methods and A Producer's Point ...

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ALKALI AGGREGATE REACTION IN NZ CONCRETE

2018-11-5  to concrete structures needs to be managed during construction by selecting appropriate concrete materials and mix designs. The most common type of AAR is alkali silica reaction (ASR), which occurs with some types of silica minerals found in many of the rock types used as concrete aggregate

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Causes of Damage to Concrete-Alkali aggregate reaction ...

The repairing of concrete actively undergoing aggregate alkali reaction considered useless because the continues expansion of concrete will disrupt and damage the repaired portion. Structures undergoing active deterioration should be monitored for the rate of expansion and movement, and only the repairs necessary to maintain safe operation of ...

Get price

MODELLING OF ALKALI-AGGREGATE REACTION IN

2020-11-6  MODELLING OF ALKALI-AGGREGATE REACTION IN CONCRETE PILE CAPS STRUCTURES Marco Juliani1*, Lucas Juliani1, Tiago Juliani1, Daniela David1, Liana Becocci1 1IEME BRASIL Engenharia Consultiva, São Paulo, SP, BRAZIL Abstract Many concrete reinforced structures throughout the world are suffering from deteriorations

Get price

[PDF] Modelling of Alkali-aggregate Reaction Effects in ...

Corpus ID: 136287169. Modelling of Alkali-aggregate Reaction Effects in Reinforced Concrete Structures @inproceedings{Jurcut2015ModellingOA, title={Modelling of Alkali-aggregate Reaction Effects in Reinforced Concrete Structures}, author={A. Jurcut}, year={2015} }

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Diagnosis of concrete structures distress due to alkali ...

Alkali-aggregate reaction (AAR) occurs either as alkali-silica reaction (ASR) or alkali-carbonate reaction (ACR). Due to more common occurrence of aggregates con-taining reactive silica minerals, alkali-silica reaction is more often the cause of serious deterioration of concrete structures. Alkali-silica reactivity was recognized as a potential ...

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Predicting the incidence of alkali-aggregate reaction in ...

Alkali-aggregate reaction (AAR) is a prominent degradation mechanism of concrete structures, which results from the dissolution of reactive silicate aggregates and the associated formation of damaging, expansive AAR gels.

Get price
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