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  • 15 Factors Affecting Durability of Concrete

    13. Alkali Aggregate Reaction. Alkali-aggregate reaction or alkali-silica reaction, takes place between alkali content of cement and silica content of aggregates is also a major factor effecting durability of concrete. Due to this reaction, Concrete expansion occurs which finally lead to severe cracking and concrete gets deteriorated.

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  • Alkali Content of Concrete Mix Water and Aggregates

    Alkali Content of Concrete Mix Water and Aggregates Introduction Alkali silica reaction (ASR) is a chemical reaction between some types of aggregate and the highly alkaline pore water present in all Portland cement concretes. When the concrete contains sufficient moisture, alkalis and reactive aggregate the reaction produces

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  • (PDF) Alkali-Aggregate Reaction (AAR) of Concrete

    Alkali-Aggregate Reaction (AAR) of Concrete Structures

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  • Aggregate Reaction - an overview | ScienceDirect Topics

    Alkali-aggregate reaction (AAR) is a reaction between the alkali hydroxides present in the pore solution of concrete and certain constituents of some aggregates; under certain conditions the reaction may produce deleterious expansion and cracking of the concrete. There are two distinct types of alkali-aggregate reaction in concrete; these are

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  • Aggregates for Concrete

    The aggregate is tested using ASTMC1293, Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction (Concrete Prism Test), commonly called CPT. Because this test takes one year to complete, a rapid assessment test, in the form of ASTM C1260 (AASHTO T 303), Potential Alkali-Reactivity of Aggregates (Mortar-Bar

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  • (PDF) Alkali-Aggregate Reaction (AAR) of Concrete

    Alkali-Aggregate Reaction (AAR) of Concrete Structures

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  • 1Joe Logan 10-22-08 SCLB Presentation

    Alkali Aggregate Reaction Carbonation Shrinkage Early Frost Damage Plastic Settlement Plastic Shrinkage Thermal Freeze/Thaw Spalling Seasonal Temp. Cracking Early Thermal Cracking. Loss of Support. Microsoft PowerPoint - 1Joe Logan 10-22-08 SCLB Presentation.ppt Author: jdellarocco

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  • Chemical attack in concrete - SlideShare

    Sep 29, 2014· Alkali-Aggregate Reaction • Chemical reactions between aggregate containing certain reactive constituents and alkalis (sodium and potassium salts) and hydroxyl ions released by the hydration of cement can have deleterious effects on concrete. •Granite, granite gneiss and schist, quartzite and sandstone, containing strained quartz are among

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  • Aggregate Reaction - an overview | ScienceDirect Topics

    Alkali-aggregate reaction (AAR) is a reaction between the alkali hydroxides present in the pore solution of concrete and certain constituents of some aggregates; under certain conditions the reaction may produce deleterious expansion and cracking of the concrete. There are two distinct types of alkali-aggregate reaction in concrete; these are

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  • (PDF) Comparative study of the alkali-silica reaction (ASR

    The alkali-silica reaction (ASR) is caused by the presence of reactive aggregates in contact with sufficiently alkaline pore solution and a moisture level above 80%, which leads to the formation

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  • Alkali Aggregate Reaction | Materials | Chemical Compounds

    Alkali aggregate reaction • Alkali aggregate reaction is a term mainly referring to a reaction which occurs over time in concrete between the highly alkaline cement paste and non crystalline silicon dioxide, which is found in many common aggregates. • This reaction can cause expansion of the altered aggregate, leading to spalling and loss of strength of the concrete.

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  • Alkali Aggregate reaction in Dam Structures a Review

    Alkali Aggregate Reactions available, Alkali Silica Reaction and Alkali Carbonate Reaction and this paper reviews Alkali Aggregate reaction within concrete construction. Keywords: Alkali – Aggregate Reaction, moisture, durability. 1. INTRODUCTION Concrete is the most utilized construction material across the world. Good quality

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  • Silica Fume | Seminar Report, PPT, PDF for Civil Engineering

    Feb 21, 2020· Alkali- aggregate reaction The amount of pozzolan needed for reducing the alkali - aggregate expansion depends on the reactivity of the pozzzolan. Whereas many researchers have reported that 30 to 40% replacement of a high- alkali Portland cement by a class F fly ash may be needed to control the alkali- aggregate expansion according to the ASTM

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  • Alkali-Aggregate Reaction (AAR) of Concrete Structures

    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-carbonate reaction in concrete and its implications

    Jan 15, 2014· According to Katayama, the alkali-aggregate reaction of carbonate rocks can be subdivided into three categories: (1) the ACR of dolomitic limestone that results in dedolomitisation, (2) the ACR of non-dolomitic limestone that produces reaction rims and (3) the alkali-silica reaction (ASR) of various carbonate rocks.

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  • Alkali-Silica Reaction In Concrete

    alkali-aggregate reaction. There are three types of alkali-aggregate reactions, namely the alkali-silica, alkali-silicate and akali-carbonate reactions. Deterioration due to the alkali-silica reaction is more common and this paper refers to this aspect. The alkali-silica reaction was first recognized as a problem in North American in 1940, in

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  • Alkali-silica reaction in concrete

    Less reactive aggregates often expensive or difficult to find exerting a force against surrounding concrete. Creation of alkali-silica gel – A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow - id: 174929-ZDc1Z

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  • durability PPT.pptx | Concrete | Corrosion

    * Sulfate attack * Alkali aggregate reaction * Chloride ion attack - Corrosion *Carbonation *Acid Attack * Effect on concrete in Seawater Sulfate attack * Sulfate attack denotes an increase in the volume of cement paste in concrete or mortar due to chemical action between the products of hydration of cement and solution containing sulfate, and

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  • Alkali Aggregate Reaction in Concrete - UK Essays

    Alkali Aggregate Reaction; 2.2 Alkali Aggregate Reaction. 2.2.1 Background. Thomas Stanton (Munn et. al., 2011) at California Department of Transportation detected cracking in concrete which was occurred due to certain aggregate reacting with cement alkalis for the first time; therefore he called this phenomena Alkali-aggregate reaction (AAR).

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

    Jul 16, 2019· Alkali aggregate reactions (AAR) occur when aggregates in concrete react with the alkali hydroxides in concrete producing a hygroscopic gel which, in the presence of moisture, absorbs water and causes expansion and cracking over a period of many years. This alkali-aggregate reaction has two forms, namely: Alkali-silica reaction (ASR) and Alkali-carbonate reaction (ACR). The former []

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alkali aggregate reaction ppt

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