chemical attack in concrete slideshare

Chemical attack in concrete - SlideShare

Sep 29, 2014  Chemical attack in concrete. 1. Chloride Attack Chloride attack is one of the most important aspects while dealing with durability of concrete. It primarily causes corrosion of reinforcement. Statistics have indicated that over 40% of failure of structures is due to corrosion of steel. Concrete and the Passive Layer The strongly alkaline nature ...

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Chemical attack on concrete - SlideShare

Sep 26, 2016  Concrete acts as the electrolyte, and the metallic connection is provided by wire ties, chair supports, or the rebar itself. 5. Chemical attacks: Chloride attack Sulphate attack Carbonation Alkali-aggregate attack 6. CHLORIDE ATTACK • Chloride attack is one of the most important aspects while dealing with durability of concrete.

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Chemical attack on concrete 2017 - SlideShare

Mar 07, 2017  Chemical attack is the reaction of chemical elements from exposure and moisture present in the concrete which results into deterioration of RCC structure. THE MAHARAJA SAYAJIRAO UNIVERSITY, BARODA 23/02/2017 2 CHEMICAL ELEMENT FROM + EXPOSURE MOISTURE IN CONCRETE CRACKS = IN CONCRETE OR REINFORCEMENT. 3.

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Chemical attack - SlideShare

Jan 15, 2018  9/12/2015 3 INTRODUCTION Sulphate attack is one of the most important causes of concrete deterioration. Soilds salts don’t attack concrete but when present in solution, they can react with the hydrated cement paste. Soluble sulfate (Na, Ca and Mg) is common in mining operations, chemical and paper milling industries. Sodium and calcium most ...

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Chemical attack on the durability of ... - SlideShare

Aug 18, 2016  Chemical attack on the durability of underground structures 1. Chemical attack on the durability of underground structures Workshop Middle East Concrete 2015 Abu Saleh Mohammod PhD, MICT General Manager Pudlo Middle East Building Materials L.L.C 2.

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Chemical attack on the durability of ... - SlideShare

Aug 18, 2016  Chemical attack on the durability of underground structures 1. Chemical attack on the durability of underground structures Workshop Middle East Concrete 2015 Abu Saleh Mohammod PhD, MICT General Manager Pudlo Middle

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Chemical attack in concrete - SlideShare

Mechanism of different chemical attacks in a concrete like chloride attack, sulfate attack , which causes corrosion and spalling. Other reactions are alkali ag

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Sulphate attack - SlideShare

Nov 28, 2015  3. Sulphate Attack • Increase in the volume of cement paste in concrete or mortar due to the chemical reaction between the products of HCP and solution containing sulphates. • In hardened concrete, C-A-H can react with sulphate salt from

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durability and permeability of concrete - SlideShare

Dec 04, 2018  Durability Permeability of concrete. 2. Durability • Durability of concrete is its ability to resist weathering action, chemical attack, abrasion or any other process of deterioration . • When exposed to environment durable concrete is likely to retain its original form, quality and serviceability during its lifetime. 3.

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Durability of concrete - SlideShare

Feb 06, 2017  CHEMICAL CAUSES • Attack by sulfates, acids, sea water, and also by chlorides, which induce electrochemical corrosion of steel reinforcement. • Since this attack takes place within the concrete mass, the attacking agent must be able to penetrate throughout the concrete, which therefore has to be permeable.

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Acid attack on concrete - SlideShare

Chemical compositions of the core layers in both aceticand nitric acid attacks are similarCore-layer originates due to portlandite dissolution inunaffected part of the cement paste and diffusion ofCa2+ and OH- ions towards corrosion zone where theymeet the acid diffusing from the opposite directionFormation of the core layer is noticeable only ...

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Properties of Concrete - Portland Cement Association

Sulfate Attack. Others. The durability of concrete may be defined as the ability of concrete to resist weathering action, chemical attack, and abrasion while maintaining its desired engineering properties. Concrete is exposed to a greater variety of potentially harmful exposure conditions than any other construction material.

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ABRASION RESISTANCE OF CONCRETE AND THE USE OF

Concrete deterioration primarily results from some combination of the following mechanisms: abrasion and hydraulic pressure cracking at rail seat, freeze-thaw damage, chemical attack like alkali silica reaction (ASR), and cracking under impact and frequent dynamic loads[2]. One possible solution to this problem is the use of high performance ...

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Chemical disruption - BrainKart

Chemical disruption . Resistance of concrete to chemical attack: ü The cement composition used in the concrete.. ü Conditions under which the cement paste hardened . ü All determine properties of concrete . 1Sulphate Attack . Mechanism-sulphates are found in most of the soils as calcium, potassium, sodium and magnesium sulphates.

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19 Types of cement - Cement Concrete

Nov 10, 2019  Due to the attack of sulphate in O.P.C. cement, there are chances of expansion within the framework of concrete and there are cracks and subsequent disruption. Many research found that to reduce sulphate attack, cement with low C3A content better results. Sulphates resisting cement has a high silicate content that is with low C3A and low C4AF.

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Chloride Attack on Concrete Structures - Cause and ...

Prevention of Chloride Attack on Concrete Structures Several methods are available in order to prevent the effect of chlorides on concrete structures. Some of them are: Increasing the cover over the reinforcement bar. This is the simplest way to prevent chloride attack. Studies have shown that an increase in cover by one inch can increase the ...

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Notes On Concrete Durability Chapter Welcome To

The resistance of concrete to weathering, chemical attack, abrasion, frost and fire depends largely upon its quality and constituent materials. All concrete in service will be subject to chemical and physical changes. Chapter 2 seviceability and durability - LinkedIn SlideShare

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Protecting Concrete Tanks in Water and Wastewater ...

Dec 28, 2000  This expansion from within creates large tensile forces within the concrete. Since concrete is relatively weak in tension, the concrete cracks to relieve the tensile stresses (Figure 3). Once the concrete cracks, water, oxygen and aggressive chemicals can freely enter the concrete and attack the embedded rebar and the deterioration process ...

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Durability of Concrete Types of Durability and Factors ...

Feb 14, 2017  Durability is defined as the capability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties. It normally refers to the duration or life span of trouble-free performance. Different concretes require different degrees of durability depending on the exposure environment and properties desired.

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Chemical attack in concrete - SlideShare

Chemical attack in concrete 1. Chloride Attack Chloride attack is one of the most important aspects while dealing with durability of concrete. It primarily causes corrosion of reinforcement. Statistics have indicated that over 40% of failure of structures is due

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1. cement ppt - SlideShare

1. cement ppt 1. Cement: Cement is the mixture of calcareous, siliceous, argillaceous and other substances. Cement is used as a binding material in mortar, concrete, etc.

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ABRASION RESISTANCE OF CONCRETE AND THE USE OF

Concrete deterioration primarily results from some combination of the following mechanisms: abrasion and hydraulic pressure cracking at rail seat, freeze-thaw damage, chemical attack like alkali silica reaction (ASR), and cracking under impact and frequent dynamic loads[2]. One possible solution to this problem is the use of high performance ...

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Chloride Attack on Concrete Structures - Cause and ...

Prevention of Chloride Attack on Concrete Structures Several methods are available in order to prevent the effect of chlorides on concrete structures. Some of them are: Increasing the cover over the reinforcement bar. This is the simplest way to prevent chloride attack. Studies have shown that an increase in cover by one inch can increase the ...

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Concrete: Scientific Principles

Concrete has the ability to be molded or cast into almost any desired shape. Building of the molds and casting can occur on the work-site which reduces costs. Concrete is a non-combustible material which makes it fire-safe and able withstand high temperatures. It

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Durability of Concrete Types of Durability and Factors ...

Feb 14, 2017  Durability is defined as the capability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties. It normally refers to the duration or life span of trouble-free performance. Different concretes require different degrees of durability depending on the exposure environment and properties desired.

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(PDF) Corrosion of Steel in Concrete Professor Dr ...

Corrosion of Steel in Concrete Understanding, investigation and repair 2nd edition John P. Broomfield

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Repairs and Rehabilitation of Concrete Structures for ...

Resin based Repairs of Concrete The resins normally used are from epoxide, polyester, acrylic or polythene families. The application of resins for repair work requires a thorough understanding of their chemical and physical properties and their performance in the structure, particularly with the passage of time and under unfriendly environs.

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CORROSION OF CONCRETE REINFORCEMENT – CAUSES REMEDIES ...

Dec 23, 2015  Corrosion of Concrete Reinforcement Corrosion is a chemical process of destruction of material because of its reaction with the environmental conditions. The most predominant among various factors of corrosion is the atmospheric corrosion which causes the rusting of steel. Appreciable corrosion only starts when the relative humidity of the air exceeds around 65%. In dry, []

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Cement - The major cements: composition and properties ...

Set cement and concrete can suffer deterioration from attack by some natural or artificial chemical agents. The alumina compound is the most vulnerable to chemical attack in soils containing sulfate salts or in seawater, while the iron compound and the two calcium silicates are more resistant. Calcium hydroxide released during the hydration of ...

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Protecting Concrete Tanks in Water and Wastewater ...

Dec 28, 2000  This expansion from within creates large tensile forces within the concrete. Since concrete is relatively weak in tension, the concrete cracks to relieve the tensile stresses (Figure 3). Once the concrete cracks, water, oxygen and aggressive chemicals can freely enter the concrete and attack the embedded rebar and the deterioration process ...

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Plant Engineering Corrosion: Chemical oxidation

Feb 11, 2011  Concrete corrosion. Corrosion in concrete can happen two ways, through the reinforcement bars and through chemical attack. Corrosion of the concrete though the reinforcement bars is a form of electrochemical corrosion because of the moisture that makes its way to the bars through the concrete since it’s very porous.

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Notes On Concrete Durability Chapter Welcome To

The durability of concrete depends on its resistance to deterioration and the environment in which it is placed. The resistance of concrete to weathering, chemical attack, abrasion, frost and fire depends largely upon its quality and constituent materials. All concrete in service will be subject to chemical and physical changes. Page 14/31

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High performance concrete ppt - es.slideshare

Concrete may be regarded as high performance for several different reasons: Very low porosity through a tight and refined pore structure of the cement paste. Very low permeability of the concrete High resistance to chemical attack. Low heat of hydration High early strength and continued strength development Low water binder ratio Low bleeding ...

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