alkali silica reaction ppt

Alkali-Silica Reaction: Causes and Solutions| Concrete ,Know More

Mar 14, 2013· Alkali-silica reactivity, better known as ASR, has openly been with us since the early1940s when it was discovered in California and publicized by TE Stanton Over seven decades later, occurrences of this reaction may actually be increasing, despite our vast knowledge about ASR gained over these years

Alkali–silica reaction - WikipediaKnow More

The alkali–silica reaction (ASR), 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

Alkali-aggregate expansion inhibiting admixtures ,Know More

Many concrete structures have exhibited deterioration due to the alkali-aggregate expansion reactions A review has been prepared to describe the nature of the alkali-aggregate reactions, test methods that are adopted to evaluate the aggregates for their potential to cause expansion and the methods suggested to counter this reaction

Laser scanning confocal microscopy for in situ monitoring ,Know More

Expansion in concrete caused by swelling of alkali–silica reaction (ASR) gel is a concern in areas of the world where the materials available for concrete construction include aggregate containing potentially reactive silica and high-alkali cementitious and pozzolanic materials

Durability of Concrete - University of WashingtonKnow More

Concrete Technology Durability of Concrete Professor Kamran M Nemati Winter Quarter 2015 4 Concrete Technology 7 Alkali-Silica Reaction (ASR) Signs of ASR Expansion and cracking Loss of strength Pop-outs and exudation of viscous alkali-silicate fluid

NRC: Special NRC Oversight at Seabrook Nuclear Power Plant ,Know More

Alkali-Silica Reaction Monitoring and Closure of NOV for Failure to Complete Operability Determinations for ASR-affected Structures – NRC Inspection Report 05000443/2016004, Sections 4OA2 and 4OA5: 01/13/2017: NRR Audit Plan for Seabrook Alkali-Silica Reaction ,

Standard Specification for Silica Fume Used in ,Know More

C1240-15 Standard Specification for Silica Fume Used in Cementitious Mixtures , Standard Specification for Silica Fume Used in Cementitious Mixtur Active Standard ASTM C1240 | Developed by , for Effectiveness of Pozzolans or Ground Blast-Furnace Slag in Preventing Excessive Expansion of Concrete Due to the Alkali-Silica Reaction

CCANZ - Alkali Aggregate ReactionKnow More

Alkali-aggregate Reactions Some aggregates containing reactive silica will react with the alkalies in cement - sodium and potassium oxides - to form an alkali-silica gel which takes up water and swells This causes abnormal expansion and map-cracking of the concrete

Alkali Aggregate Reaction in Concrete - Types, Causes, and ,Know More

This alkali-aggregate reaction has two forms, namely: Alkali-silica reaction (ASR) and Alkali-carbonate reaction (ACR) The former is of higher concern since aggregates containing various forms of silica materials are very common whereas the latter occurs rarely because of the unsuitability of carbonates for use in concrete

Alkali silica reactivity - SlideShareKnow More

May 05, 2015· Alkali silica reactivity 1 ALKALI-SILICA REACTIVITY (ASR) 2 What is ASR? is a reaction between alkali hydroxide and Silica particles from aggregate that happened in concrete 3 Why is it dangerous? Because : • 1 Alkalies + Reactive Silica → Gel Reaction Product • 2 Gel Reaction Product + Moisture → Expansion 4

Approaches to Mitigate Alkali Silica Reaction (ASR ,Know More

Approaches to Mitigate Alkali Silica Reaction (ASR) Effects at Airports II BACKGROUND Alkali silica reaction (ASR) is pervasive problem in concrete structures in nearly all 50 states in the US ASR occurs when siliceous aggregate reacts with cement alkali hydroxides within the concrete matrix por The reaction creates a gel substance, alkali

Asr Theory Final | Silicon Dioxide | ConcreteKnow More

Asr Theory Final - Free download as Powerpoint Presentation (ppt), PDF File (pdf), Text File (txt) or view presentation slides online Alkali silica reaction

Types of Chemical Attacks on Concrete StructuresKnow More

Alkali-Aggregate reaction on concrete Alkali aggregate reaction is the chemical reaction between alkali in cement and silica content of aggregat Hence it can also be called as Alkali Silica reaction When this reaction takes place, a gel like substance is formed which absorbs water and volume of concrete will increase

REPORT ON ALKALI-AGGREGATE PROBLEMS ON ,Know More

There are two types of recognized alkali-aggregate reaction: alkali-silica reaction (ASR) and the much rarer alkali-carbonate reaction (ACR) In each case, alkalis present in concrete from portland cement, fly ash, admixtures, aggregates, or other sources, react with certain siliceous

CIP 43 - National Ready Mixed Concrete AssociationKnow More

Title: CIP 43pdf Author: sdickens Created Date: 2/5/2014 2:42:38 PM

Concrete Alkali Silica Reaction Presentation - YouTubeKnow More

Nov 18, 2011· Dr Jason Eidiker of Oregon State University Presents His Research on Alkali Silica Reaction of Concrete

Alkali Silica Reaction - MechanismKnow More

Alkali Silica Reaction - Mechanism The Reaction Alkali—sodium, potassium, and lithium—are generally introduced into concrete weakly bonded to hydroxyl ions, (OH)-, by the cementHowever, alkali also may be present in pozzolans, aggregate, admixtures, and mix water used to make the concrete

Understanding CementKnow More

Basic Information Over thirty articles on cement manufacturing, cement hydration and deleterious processes in concrete See the Article Directory or the drop-down menus to get started

Alkali-Carbonate Rock ReactionKnow More

into the nature of the reaction, methods of test and identification, and some hypotheses concerning the mechanism of reaction and expansion •THE expansive type cif alkali-carbonate rock reaction in concrete has now been estab­ lished as a phenomenon quite distinct from the better known alkali-silica reaction,

ALKALI AGGREGATE REACTIONS (AAR) IN CONCRETEKnow More

Alkali Aggregate Reactions (AAR) in concrete , It is well documented that for alkali-silica reaction to occur, three conditions must be present: aggregate with reactive forms of silica, high-alkali (pH) pore solution, and sufficient moisture [2] In the following a description of each of these factors concerning Finnish practise (reality) is

PPT – Alkali-Silica Reaction: PowerPoint presentation ,Know More

Possible ASR damage on concrete retaining wall - picture taken 1/2002 , damage includes the presence of gel and staining Creation of alkali-silica gel , – A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow - id: 1e1319-ZDc1Z

Alkali-Aggregate Reactivity (AAR) Facts BookKnow More

This document provides detailed information on alkali-aggregate reactivity (AAR) It primarily discusses alkali-silica reaction (ASR), cover­ ing the chemistry, symptoms, test methods, prevention, specifica tions, diagnosis and prognosis, and mitigation Alkali-carbonate reaction (ACR) is also addressed

Alkali-Silica Reaction In Concrete - Civil EngineeringKnow More

ALKALI-SILICA REACTION Alkali-silica reaction (ASR) in concrete is a reaction between certain silicious constituents in the aggregate and the alkali-sodium and potassium hydroxide which are released during the hydration of Portland cement

Alkali–silica reaction: Current understanding of the ,Know More

1 Introduction Alkali–silica reaction (ASR) is a deleterious reaction between the alkaline pore solution of concrete and various metastable forms of silica contained in many natural and synthetic aggregates , The silica structure is dissolved by the nucleophilic attack of OH − ions, and the highly degraded silica structure behaves as a hygroscopic silica gel

Alkali-Aggregate Reaction (AAR) of Concrete StructuresKnow More

Alkali-Aggregate Reaction (AAR) of Concrete Structur Outline • What is AAR? • How does AAR work? , structures? AAR • Alkali-silica Reaction (ASR): - only type of AAR occurred in HK • Alkali-silicate Reaction • Alkali-carbonate Reaction Concrete failure due to ASR Concrete failure due to ASR Effect of ASR • Concrete Quality

Alkali-aggregate expansion inhibiting admixtures ,Know More

The effectiveness of silica fume depends on a number of parameters, such as composition (SiOz and alkali contents), the percentage used, the type of alkali aggregate expansion reaction (alkali-silica or alkali- carbonate) and the type, fineness and alkali contents of cement

Topics on Alkali-Silica Reaction - Development BureauKnow More

Alkali­SilicaReaction (ASR) is a result of reaction between the alkalinepore solution and reactive silica in the aggregate The reactionleads to the formation of a gel which absorbs water and expandsleading to damaging expansions and cracking in the concrete

(PDF) Alkali-aggregate reaction in concrete: A review of ,Know More

Alkali-aggregate reaction in concrete: A review of basic concepts and engineering implications , The distress caused by alkali-silica reaction (ASR) to concrete structures can occur long time .

Alkali-Aggregate ReactionKnow More

Alkali-silica reaction (ASR) is of more concern because aggregates containing reactive silica materials are more common In ASR, aggregates containing certain forms of silica will react with alkali hydroxide in concrete to form a gel that swells as it adsorbs water ,

Supplementary Cementitious Materials - PCAKnow More

Alkali-Silica Reactivity (Detwiler 2002) Alkali-silica reactivity can be controlled through the use of SCMs The chart shows the effect of different fly ashes and slag on alkali-silica reactivity Note that some ashes are more effective than others in controlling the reaction and that dosage of the ash or slag is critical A highly