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Types and Causes of Concrete Deterioration

half-cell oxidation reaction or the anodic reaction and is represented as 2Fe → 2Fe2+ + 4e-The electrons remain in the bar and flow to sites called cathodes where they combine with water and oxygen in the concrete The reaction at the cathode is called a reduction reaction A common reduction reaction is 2H 2O + O 2 + 4e-→ 4OH-Get price


permissible limit of reactivity minerals aggregate

Alkali Aggregate Reaction (AAR) is a chemical reaction of alkali in concrete and certain alkaline reactive minerals in aggregate producing a hygroscopic gel which Learn More permissible limit of reactivity minerals aggregate Read More permissible value of aggregates impact value Get price


Similarity between alkali–aggregate reaction and the

Read Similarity between alkali–aggregate reaction and the natural alteration of rocks Cement and Concrete Research on DeepDyve the largest online rental service for scholarly research with thousands of academic publications available at your fingertips Get price



5-10-2016The contribution covers results of studies on the alkali-activated cement concretes intended for marine engineering applications Such properties as strength wear corrosion freeze-thaw weather resistance and many others have been studied and the results are reported and discussed in detail The obtained results suggested to draw Get price


Toxicity and environmental and economic performance of

This paper presents an overview of previous studies on the environmental impact (EI) and toxicity of producing recycled concrete aggregates (RCA) fly ash (FA) cement superplasticizer and water as raw materials and also on the effect of replacing cement and natural aggregates (NA) with FA and RCA respectively on the mentioned aspects EI Get price


Concrete Pavement Maintenance / Repair

and alkali-aggregate reaction (AAR) d-cracking is D-shaped hairline cracks that occur near joints cracks and free edges when certain aggregates in a concrete become saturated freeze and expand The expansion causes the surrounding concrete matrix to crack Alkali-Aggregate reaction is caused by a chemical reaction that occurs when free alkalisGet price


Fly Ash Slag Silica Fume and Natural Pozzolans Chapter 3

alkali-silica reaction The most common natural pozzolans used today are processed materials which are heat treated in a kiln and then ground to a fine powder (Figs 3-10 3-11 and 3-12) they include calcined clay calcined shale and metakaolin ground granulated blast furnace slag and ACI 233 (1995) provides an extensive review of slag Get price


Use of Recycled Aggregate Concrete

cement could be offset by the lower cost of Recycled Concrete Aggregate (RCA) 20% cement replaced by fly ash is found to control alkali silica reaction (ASR) Save environment - There is no excavation of natural resources less transportation Also less land is required Save time - There is no waiting for material availability Get price



Your Alert Profile lists the documents that will be monitored When different sizes are combined the void-content decreases Different aggregate grading may have the same FM ASTM C Clay Lumps and Friable Particles in Aggregate | CTLGroup We think you have liked this presentation Cracking of concrete from alkali-silica reactivity Get price


slag aggregate to concrete pdf

2013812-Keywords Steel slag aggregate Concrete Fire resistance Residual properties Microstructural analysis Download full text in PDF granulated steel slag aggregate in concrete__ 201648- 3 DOC PPT TXT PDF 18 Standard Test Method for Determination of Length Change of Concrete Due to Alkali-Silica Reaction aggregate alkali-silica Get price



Many cases of alkali-aggregate reactions (AAR) have been described in commercial and residential buildings foundations of Recife Metropolitan Area There have not been found in literature AAR cases by arnbat in Types Research Science reao alcali agregado and alkaliaggregate reactionGet price


Sulfate attack in concrete

Commonly associated with alkali-silica reaction (ASR) In laboratory tests limestone coarse aggregate has been found to reduce expansion DEF usually occurs in concrete which has either been steam cured or which reached a high temperature during curing as a result of the exothermic reaction Get price


Alkali–carbonate reactions and 'dedolomitization' in

Adverse reactions between specific aggregate particles and the pore fluids in cement pastes have been widely reported and have been regarded as responsible for the failure of the structures into which the resulting concrete had been emplaced The reactivity of aggregates containing various forms of silica has been well understood but similar Get price


Experimental research on the mechanical properties of

Alkali excitant usually refers to caustic alkali and silicate containing the alkaline element phosphate aluminate sulfate carbonate and so on Its hydration reaction on the geopolymer provided an alkaline and displayed a catalytic action It also provided free silicate ions which caused a polymerization reaction Get price


Lightweight Aggregate Concrete

28-10-2002Purchase Lightweight Aggregate Concrete - 1st Edition receive and download all of Lightweight Aggregate Concrete to Chemical Attack Introduction Acid Resistance Alkali-Aggregate Reaction Carbonation and Corrosion Chloride Ion Penetration Fire Resistance of Lightweight Aggregate Concrete Get price


ASR Field Identification Handbook

ASR Field Identification Handbook Download PDF Comment 4MB Size 11 Downloads 75 Views OREWORD This field identification handbook provides guidance in identifying alkali-silica reactivity (ASR) in concrete field structures Abstract Two types of alkali-aggregate reaction (AAR) Get price



The pozzolanic reaction can also reduce the risk of expansive alkali-silica reactions between the cement and aggregates by changing the binder pore solution Lowering the solution alkalinity and increasing alumina concentrations strongly decreases or inhibits the dissolution of the aggregate Get price


Project Report – Six Months Summer Training

Project Report – Six Months Summer Training Pozzolana combines with lime and alkali in cement when water is added and forms compounds which contribute to strength It also contributes to workability reduced bleeding and controls destructive expansion from alkali-aggregate reaction Get price


CONCRETE Optimizing the Use of Fly Ash in Concrete

1995) controlling expansion due to alkali-silica reaction (Shehata 2000) and providing resistance to sulfate attack (Shashiprakash 2002) These issues are addressed in sections Effect of Fly Ash on the Properties of Fresh Concreteand Durability Figure 4 shows the distribution in Get price


alkali aggregate reaction ppt descargar

chemguide copper complex physical properties alkali aggregate reaction ppt descargar Alkali metalWikipedia the free encyclopedia The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li) soPropertiesCompoundsExtensions # Get Price Ms informacin Get price


aggregate sampling methods rifling

2009-11-01 As 1141111-2009 Methods for Sampling and Testing Aggregates Particle Size Distribution - Sieving Method - Free download as PDF File (pdf) Text File (txt) or read online for free Scribd is the world's largest social reading and publishing site Get Info sampling from conveyor belt for aggregate pptGet price


Alkali silica reactivity

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 Get price


recycled aggregate concrete ppt download

RECYCLED CONCRETE AGGREGATE ppt video online download Recycled concrete aggregates (RCA) contain not only the original aggregates but also hydrated cement paste Recycling of aggregate can take place either at the site from which the material is sourced using mobile crushers Get price



viii) Alkali content 0 05 (for prestressed structures see Note) NOTE — Alkali aggregates reactions have been noticed in aggregates in some parts of the country On large and important jobs where the concrete is likely to be exposed to humid atmosphere or wetting action it is advisable that the aggregate be tested for alkali aggregate reaction Get price


What is an Admixture

CivilDigital Civil Engineering Articles Civil Engineering Articles for Mobile What is an Admixture | Functions of Admixtures What are Admixtures Air Entraining Admixtures Alkali-Aggregate Reaction Inhibiting Admixtures cement cement admixture cement companies cement products Get price


nano technology in concrete ppt

Nano Concrete Seminar Report and PPT Why nanotechnology for concrete?Improves the materials' volume properties Ability to control or handle materials at the atomic scale NANOSCALE ATTACK ON ASR (ALKALI SILICATE REACTION) To attain thinner ultimate products and rapid setting time Cost usefulness and Lowered levels of environmental spoliation Get price


Was ist AAR

03-berblich ppt (deutsch) 1 Fachtagung Alkali Aggregat Reaktion 1 16 November 2005 Fachtagung Alkali Aggregat Reaktion 16 November 2005 Th Henoch Was ist AAR ? Thomas Henoch alkali-aggregate reaction (AAR) raction alcali-granulat (RAG) Fachtagung Alkali Aggregat Reaktion 16 November 2005 Th HenochGet price


application of recycled aggregate concrete produced by

application of recycled aggregate concrete produced by aggregate replacing method ppt download Recycled Aggregate the method of construction area of application form of hydration reaction Details of these various types of concrete their properties and recycling concrete construction field alkali-silica-reaction fine aggregate Get price


Types of Admixtures of Concrete Cement

Alkali and sulfate (SO4) contents are generally higher in Class C fly ashes In addition to economic and ecological benefits the use of fly ash in concrete improves its workability reduces segregation bleeding heat evolution and permeability inhibits alkali-aggregate reaction and enhances sulfate resistance Get price


Alkali aggregate reaction

Alkali aggregate reaction 1 BY AKRAM AFRIDI 2 Alkali-Aggregate Reaction Is the reaction between the active mineral constituents of some aggregates and the sodium and potassium alkali hydroxide in the concrete Harmful only when it produes significant expansionGet price

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