alkali silica reaction ppt


Alkali-silica reaction gels are composed of two-component mixtures of alkali-calcium-silicate hydrate and alkali-silica sols of nearly fixed compositions. Cracking

Durability of Concrete - University of Washington

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

Mitigating Alkali-Silica Reaction - Slag Cement

Alkali-silica reaction (ASR) is a chemical reaction between the alkalis in portland cement and certain types of silica minerals present in some aggregates. The reaction product is a hygroscopic gel, which absorbs moisture and swells.

Topics on Alkali-Silica Reaction - Development Bureau

Fluorescencemicroscopy image ­Source:Mircolab. Alkali­SilicaReaction (ASR) is a result of reaction between the alkalinepore solution and reactive silica in the aggregate.

NZRMCA Technical Note 1 Alkali Silica Reaction …

Alkali Silica Reaction Precautions for Normal Concrete Published by the Technical Committee, NZRMCA, May 2004 . Alkali Aggregate Reaction Precautions for Normal Concrete 1 May 2004 Alkali Silica Reaction Precautions for Normal Concrete Contents ... Alkali Silica Reaction. The revised version of TR 3, some 90 pages, has been …

Alkali Silica Reaction - CAIT

Silica in aggregates reacts with alkali in cement to produce a gel. Step Two: The gel absorbs water, causing expansion and hydraulic pressures sufficient to fracture and break apart the concrete. Process Requirements: ... Change of Concrete Due to Alkali Silica Reaction

Alkali-Aggregate Reaction (AAR) of Concrete Structures

• Alkali-silica Reaction (ASR): ... • Premature failure of concrete structures • Economic Costs • Maintenance cost increased • The life of concrete structure is reduced • Overall Result • No concrete structures had collapsed due to ASR damage ... Microsoft PowerPoint - ACS - AAR.ppt

Alkali-Silica Reaction: Causes and Solutions| Concrete ...

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

Alkali-Aggregate Reaction -

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 …

Alkali silica reactivity - SlideShare

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 ... 4. Illustration concrete Reaction Alkali-silica gel Gel absord water Gel swells Crack in concrete 5. Solution • Use Fly Ash Because 6. ... PowerPoint Essential ...

Alkali-Silica Reaction In Concrete - IDC-Online

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 …

tech talk Alkali Silica Reactions - NRMCA Expanding the ...

A lkali silica reaction (ASR) is a con-crete durability problem whereby certain forms of silica in aggregates react in high alkaline pore solutions in con-

Chapter 2 Alkali-Silica Reaction - Guidelines for The Use ...

The term alkali-silica reaction is somewhat misleading- the reaction itself is actually between the OH-ions in the pore solution and certain siliceous components of the aggregates. The alkalies, specifically sodium and potassium, do not actually attack the reactive silica.

Alkali-Silica Reaction (Concrete Cancer) – Overview

Alkali-silica reaction - overview Barrage damaged due to an alkali-silica reaction In an alkali-silica reaction (ASR) alkali-sensitive SiO 2 constituents in the aggregates react with the alkali and hydroxide ions (K + , Na + and OH - ) in the pore solution of the concrete to form an alkali silica gel with a tendency to absorb water.

Alkali-silica reaction in concrete - Understanding Cement

Alkali-silica reaction in concrete. Alkali-silica reaction (ASR) can cause serious expansion and cracking in concrete, resulting in major structural problems and sometimes necessitating demolition. This is a short introduction to ASR - for more information, see the Understanding Cement book/ebook.

Alkali-silica reaction in concrete - UPCommons

The expansive reactions between alkalis and reactive aggregates within concrete alkali- structures are a problem which has been known about since the mid 20 th century.

A Critical Assessment to the Performance of Alkali-Silica ...

Abstract: Alkali-silica reaction is one of the most recognized deleterious phenomenon in concrete that results in excessive expansion, cracks, loss in mechanical properties and serviceability problems.

CONCRETE TECHNOLOGY Diagnosis and Control of …

The alkali-silica reaction forms a gel that swells as it draws water from the surrounding cement paste.Reaction 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 paste.The

PPT – Alkali-Silica Reaction: PowerPoint presentation ...

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PPT – Alkali-Silica Reaction: PowerPoint presentation ...

Alkali-Silica Reaction: - PowerPoint PPT Presentation. The presentation will start after a short (15 second) video ad from one of our sponsors. Hot tip: Video ads won’t appear to registered users who are logged in. And it’s free to register and free to log in!

CIP 43 - NRMCA Expanding the Concrete Industry Through ...

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

Concrete Alkali Silica Reaction Presentation - YouTube

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

Investigation of ASR expansion due to total alkali and ...

Alkali-silica reaction (ASR) is a heterogeneous chemical reaction between alkali ions (Na+ and K+) and hydroxide ions (OH-) in the concrete pore solution, generally derived from the Portland cement, and forms of reactive silica (SiO

Alkali–Silica Reactions: An Overview. Part I | SpringerLink

In 1940, Stanton recognized for the first time alkalis, Na and K, in the paste combined with silica from the aggregate, in a deleterious reaction dubbed ‘alkali–silica reaction’ (ASR) (see [27, entry 1008]).

Alkali Silica Reaction - an overview | ScienceDirect Topics

Briefly, alkali-silica reaction is a reaction between the alkali hydroxides in the pore solution of concrete and thermodynamically unstable silica in certain aggregates. The reaction product is an alkali-silica gel (of varying composition) which has the tendency to imbibe water and swell.

CCANZ - Alkali Aggregate Reaction

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.

Alkali Silica Reaction (ASR) Degradation in Nuclear ...

In this session, speakers will describe current research on the effects of Alkali‐ Silica Reaction (ASR) degradation on the structural capacity of nuclear concrete structures.

Alkali-Silica Reaction (ASR) -

Alkali-Silica Reaction (ASR) Prohibitinguse of Class C Fly Ash. Sufficient Alkali Reactive Silica eactive grega Alkalies in Pore Solution eactive ggrega Si02 Alkalies Breakdown Aggregate and Release ... Microsoft PowerPoint - Final ASR Poster [Compatibility Mode] Author: dor9007

Alkali–silica reaction - Wikipedia

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 Silica Reaction | Silicon Dioxide | Concrete

Alkali-silica reaction (ASR) Concrete can be damaged by a chemical reaction between the active silica constituents of the aggregate and the alkalis in the cement; this process is known as alkali – silica reaction.