Electrochemical Extraction (ECE)
•Download as PPTX, PDF•
1 like•805 views
This document discusses electrochemical chloride extraction (ECE), a process for removing chloride ions from contaminated concrete and repassivating steel reinforcement. ECE works by applying an external anode and electrolyte to the concrete surface and passing a direct current between the anode and steel reinforcement cathode. This drives chloride ions out of the concrete and increases alkalinity around the steel to repassivate it. The document covers the ECE process, advantages like long-term protection with few standards, and disadvantages such as potential side effects from high current densities. It also summarizes several experimental studies on factors affecting chloride extraction effectiveness.
Report
Share
Report
Share
Recommended
chloride attack and sulphate attack on concrete
This document discusses chloride and sulfate attack on concrete. Chloride attack is a major cause of reinforcement corrosion, accounting for 40% of structure failures. Chlorides enter concrete through water, cement, aggregates or admixtures and exist in both bound and free forms, with free chlorides causing corrosion. Sulfate attack results in the formation of gypsum and ettringite, increasing concrete volume and causing disintegration. Preventative measures for chloride attack include proper cover, epoxy coatings, and permeability reduction. Sulfate attack can be controlled through the use of sulfate-resistant cement, quality concrete work, and pozzolanas or high alumina cement.
Chemical attack in concrete
Mechanism of different chemical attacks in a concrete like chloride attack, sulfate attack , which causes corrosion and spalling. Other reactions are alkali aggregate reaction , alkali silica reaction in concrete etc.
corrosion and protection of steel reinforced c...
Corrosion of steel reinforcement in concrete is an electrochemical process that occurs when oxygen, water and chlorides penetrate the concrete and reach the steel. It results in rust formation which expands and cracks the concrete. Chlorides from deicing salts or seawater and carbonation are the primary causes of corrosion. Methods to prevent corrosion include using epoxy-coated rebar, thermally sprayed zinc or aluminum coatings, fly ash concrete, cathodic protection systems, and corrosion inhibitors. Titanium mesh anodes can provide cathodic protection without needing power sources.
Geopolymer concrete
The document discusses geopolymer concrete as an alternative to traditional Portland cement concrete. It defines geopolymer concrete as a material made through a chemical reaction of aluminosilicate materials like fly ash or slag with an alkaline solution. This reaction forms a three-dimensional polymeric chain and network. In contrast to Portland cement, water is not involved in the chemical reaction and curing of geopolymer concrete. The document outlines the constituents, properties, applications and limitations of geopolymer concrete. It notes the potential for geopolymer concrete to provide environmental benefits over traditional concrete.
Concrete corrosion
Concrete is a composite material made of cement, sand, gravel and water. It can be classified as low, medium or high strength based on its compressive strength. Proper curing is important to achieve maximum properties. Different types of cement and reinforcement fibres are used in concrete. Concrete is susceptible to corrosion from chlorides, sulphates and carbonation which can be prevented through methods like coatings, cathodic protection and using galvanized reinforcement. Models exist to predict corrosion rates based on factors like resistivity and chloride content.
corrosion of steel reinforcement in concrete
It includes mechanism of corrosion of steel reinforcement in concrete. It includes concepts like passivation, chloride ingress and chloride binding. It deals with the durablity aspects of a concrete structure.
Deterioration of concrete ppt
Deterioration of concrete structures can occur through various chemical, physical, and mechanical processes over time. Scaling and disintegration are forms of physical deterioration where the concrete's surface layers break down from freezing and thawing or weathering. Corrosion of reinforcement rebar can develop due to penetration of chloride ions or carbonation reducing the pH. Other causes include sulfate attack, alkali-aggregate reactions, abrasion, high temperatures, and erosion. Proper mix design and concrete quality can increase durability and prevent deterioration.
Structural Strengthening
Structural strengthening, restoring and adding capacity is an integral part of today’s concrete repair industry. Structural strengthening may be required for increasing load capacity of beams, columns, walls, and/or slabs, seismic retrofitting, supporting additional live or dead loads not included in original design, to relieve stresses generated by design or construction errors, or to restore original load capacity to damaged structural elements.
Recommended
chloride attack and sulphate attack on concrete
This document discusses chloride and sulfate attack on concrete. Chloride attack is a major cause of reinforcement corrosion, accounting for 40% of structure failures. Chlorides enter concrete through water, cement, aggregates or admixtures and exist in both bound and free forms, with free chlorides causing corrosion. Sulfate attack results in the formation of gypsum and ettringite, increasing concrete volume and causing disintegration. Preventative measures for chloride attack include proper cover, epoxy coatings, and permeability reduction. Sulfate attack can be controlled through the use of sulfate-resistant cement, quality concrete work, and pozzolanas or high alumina cement.
Chemical attack in concrete
Mechanism of different chemical attacks in a concrete like chloride attack, sulfate attack , which causes corrosion and spalling. Other reactions are alkali aggregate reaction , alkali silica reaction in concrete etc.
corrosion and protection of steel reinforced c...
Corrosion of steel reinforcement in concrete is an electrochemical process that occurs when oxygen, water and chlorides penetrate the concrete and reach the steel. It results in rust formation which expands and cracks the concrete. Chlorides from deicing salts or seawater and carbonation are the primary causes of corrosion. Methods to prevent corrosion include using epoxy-coated rebar, thermally sprayed zinc or aluminum coatings, fly ash concrete, cathodic protection systems, and corrosion inhibitors. Titanium mesh anodes can provide cathodic protection without needing power sources.
Geopolymer concrete
The document discusses geopolymer concrete as an alternative to traditional Portland cement concrete. It defines geopolymer concrete as a material made through a chemical reaction of aluminosilicate materials like fly ash or slag with an alkaline solution. This reaction forms a three-dimensional polymeric chain and network. In contrast to Portland cement, water is not involved in the chemical reaction and curing of geopolymer concrete. The document outlines the constituents, properties, applications and limitations of geopolymer concrete. It notes the potential for geopolymer concrete to provide environmental benefits over traditional concrete.
Concrete corrosion
Concrete is a composite material made of cement, sand, gravel and water. It can be classified as low, medium or high strength based on its compressive strength. Proper curing is important to achieve maximum properties. Different types of cement and reinforcement fibres are used in concrete. Concrete is susceptible to corrosion from chlorides, sulphates and carbonation which can be prevented through methods like coatings, cathodic protection and using galvanized reinforcement. Models exist to predict corrosion rates based on factors like resistivity and chloride content.
corrosion of steel reinforcement in concrete
It includes mechanism of corrosion of steel reinforcement in concrete. It includes concepts like passivation, chloride ingress and chloride binding. It deals with the durablity aspects of a concrete structure.
Deterioration of concrete ppt
Deterioration of concrete structures can occur through various chemical, physical, and mechanical processes over time. Scaling and disintegration are forms of physical deterioration where the concrete's surface layers break down from freezing and thawing or weathering. Corrosion of reinforcement rebar can develop due to penetration of chloride ions or carbonation reducing the pH. Other causes include sulfate attack, alkali-aggregate reactions, abrasion, high temperatures, and erosion. Proper mix design and concrete quality can increase durability and prevent deterioration.
Structural Strengthening
Structural strengthening, restoring and adding capacity is an integral part of today’s concrete repair industry. Structural strengthening may be required for increasing load capacity of beams, columns, walls, and/or slabs, seismic retrofitting, supporting additional live or dead loads not included in original design, to relieve stresses generated by design or construction errors, or to restore original load capacity to damaged structural elements.
Corrosion Effects in Concrete
Corrosion of steel reinforcement in concrete is an electrochemical process that results in rust formation and expansion, which can crack and delaminate the concrete over time. The main causes of corrosion are chlorides and carbonation. Chlorides from deicing salts or seawater can penetrate the concrete and destroy the protective oxide layer on the steel. Carbonation occurs when carbon dioxide penetrates the concrete and raises its acidity, also damaging the protective layer. Common methods to protect reinforcement include using epoxy or zinc coatings on the steel, adding corrosion inhibitors to the concrete mix, or installing galvanic or impressed current anode systems that divert corrosion to the more easily corroded anode material.
Basics of Geopolymer concrete
This document summarizes research on geopolymer concrete as an alternative to traditional Portland cement concrete. Geopolymer concrete is made through a chemical reaction of aluminosilicate materials like fly ash with an alkaline solution, forming a three dimensional polymeric chain structure. It offers benefits over Portland cement like lower CO2 emissions in production, higher strength and durability, and the ability to utilize industrial waste materials. Some potential applications highlighted include use in coastal and cold weather construction for its chloride resistance, as well as airport runways and highways due to its heat resistance.
Service Life Prediction of RC Structure With Respect to Corrosion of Steel
This presentation discusses corrosion of steel reinforcement in reinforced concrete structures and its impact on service life. It covers the mechanisms of corrosion including carbonation-induced and chloride-induced corrosion. It also discusses various methods to control and prevent corrosion like using low water-cement ratios, supplementary cementitious materials, corrosion inhibitors, and protective coatings/catheathodic protection of the steel and coatings on the concrete. Maintaining proper concrete mix design, quality control, and reinforcement detailing can improve corrosion resistance and extend service life. Corrosion leads to cracking, loss of steel cross-section, bond degradation and reduced load capacity over time.
Concrete Corrosion of Reinforcing Steel
The document discusses corrosion of steel reinforcement in concrete and methods to minimize it. It describes how carbonation and chloride attacks can cause corrosion through electrochemical processes. Various techniques are presented to mitigate corrosion, including using epoxy coatings on rebar, adding fibers or memory alloys to concrete, using admixtures, hybrid fiber reinforced concrete, and fiber reinforced polymers applied after corrosion begins. Ongoing research gaps and a proposed future study are also mentioned.
A seminar report on control of corrosion on underwater piles
This document is a seminar report on controlling corrosion on underwater piles. It provides background on corrosion mechanisms of steel in seawater and defines zones of corrosion on steel piles. It then discusses corrosion management in three phases: assessment, physical assessment and remediation, and future monitoring. The report also describes various corrosion protection methods like protective coatings (inorganic zinc silicates primers, high build epoxy coatings, aliphatic polyurethane topcoats, zinc rich epoxy primers, non-skid deck coatings) and cathodic protection (suspension anodes, rod anodes). It gives examples of applying FRP composites on bridges to control corrosion.
2.chloride ingress in concrete
Chloride ingress is the penetration of chloride ions through pores into permeable concrete. The chloride ions come from salt containing chlorine. When chloride ions penetrate to the level of reinforcement in concrete and are in the presence of water and oxygen, they can destroy the protective iron oxide layer on the reinforcement and cause corrosion. Chloride ingress occurs through diffusion and absorption and is more likely when concrete has a high permeability from factors like a high water-cement ratio. Chloride ingress can cause expansion of concrete from corrosion, cracking as aggregates become unbonded, and chemical deterioration of reinforcing steel.
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..
The corrosion of reinforcement inside concrete is one of the factors affecting the performance of the structure. Here the presentation will enlighten you about its mechanism and other aspects.
Acid attack on concrete
This presentation gives an overview on different types of acid attacks on concrete. Mechanism of each attack is discussed with few case studies. Hope it is useful
Metakaolin
This document discusses metakaolin, which is produced by calcining kaolin clay between 650-800°C. It has pozzolanic properties and can partially replace cement in high strength concrete. Metakaolin increases the strength and durability of concrete by reacting with calcium hydroxide to produce additional calcium-silicate-hydrate gel. It improves the physical and chemical properties of concrete, leading to applications in infrastructure like bridges, dams, and buildings where high strength and durability are important.
Epoxy crack injection for concrete (the basics)
Epoxy injection offers a permanent repair for cracks (and delaminations) in concrete. The repair is structural, permanent and water-tight with the same lifespan as the surrounding concrete. It can be performed at temperatures as low 35°F, on cracks as narrow as 5 mils (5/1000”) and even underwater.
The cured epoxy restores the monolithic integrity of the concrete, protects the internal reinforcing steel from corrosion and is unaffected by water, chemicals and sunlight. University studies confirm that the repaired concrete matches the original strength of the uncracked concrete. A useful performance specification for the epoxy adhesive is ASTM C881, Type IV for load bearing (structural) applications. The cured high modulus epoxy generally exhibits more than 3 times the compressive strength and over 10 times the tensile strength of the surrounding concrete.
Typical structures repaired using epoxy injection include: parking decks, stadiums, concrete framed buildings, residential foundations, swimming pools, airport runways and taxiways, concrete bridge decks, floor cracking and delaminations in warehouses and manufacturing facilities, concrete pipe and tanks, concrete beams and piers and port facilities including docks, piers and pilings. Facilities where crack injection is often employed include water/sewage treatment plants, industrial sites, machinery foundations, and refrigerated and frozen food storage warehouses.
Specially trained contractors should be considered to properly perform crack repair using proper surface preparation procedures and positive displacement metering pumps to properly proportion and deliver the two component epoxy.
Benefits of Epoxy Injection
• Fast cure strength — up to 5,000 psi compressive yield in less than 5 hours,
• Vibration tolerant during cure — repairs can be made while structure is open,
• Unique concrete crack injection solutions for underwater, corrosive, large void (low exotherm) and other extreme exposures,
• O VOC concrete crack repair adhesives and seals,
• Can be used in temperatures as low as 35°F,
• Restores cracked concrete and structural members including beams and columns to original monolithic strength,
• Stops water leakage through foundations,
• Prevents corrosion of embedded reinforcing steel,
• Useful in secondary containment areas to prevent leaks and
• Unlike urethane chemical grouts, the epoxy crack repair is structural and permanent.
Fibre reinforced concrete
This presentation gives complete detail about the production, construction and applications with examples of Fibre Reinforced concrete.
SELF HEALING CONCRETE
Akif Perwez presented on self-healing concrete at a technical seminar. Bacteria-based self-healing concrete contains bacterial spores and nutrients that become activated when cracks form, allowing the bacteria to consume the nutrients and seal the cracks with limestone. Laboratory tests showed this concrete could self-heal cracks up to 0.8mm wide. Using this concrete could reduce costs by decreasing steel reinforcement needed and improve sustainability by reducing steel usage in waterproof applications. The presentation discussed how the bacteria-based self-healing process works, finding suitable bacteria that can survive in concrete, and full-scale testing of cracked concrete samples.
Carbonation of concrete
Carbonation is a chemical process where atmospheric carbon dioxide reacts with compounds in concrete, like calcium hydroxide, to form calcium carbonate, reducing the pH of concrete. This reaction exposes the reinforcing steel to corrosion. The depth of carbonation depends on factors like CO2 concentration, concrete pore structure, and relative humidity. Carbonation can be tested by using phenolphthalein solution, which changes color at pH 9.2, indicating the boundary between carbonated and uncarbonated concrete. Protective coatings can prevent further carbonation by providing a barrier to water and CO2 ingress.
Sulphate attack
Sulphate attack occurs when sulphates react with hardened cement paste, causing expansion and cracking of concrete. Soil sulphates do not severely damage concrete, but water sulphates can enter porous concrete and react with hydration products. This forms ettringite which increases in volume, disintegrating the concrete. Sulphate attack can be external from sulphates in groundwater penetrating concrete, or internal from sulphates in the original mix. Delayed ettringite formation is a type of internal sulphate attack where ettringite decomposes during curing then reforms, expanding and damaging the concrete.
Durability of concrete
The document discusses the durability of concrete and the factors that affect it. It defines durability as the ability of concrete to resist weathering, chemical attack, and abrasion while maintaining its desired properties. The main factors discussed are abrasion, biological factors, temperature effects, freezing and thawing, and various types of chemical attacks including carbonation, chloride attack, acid attack, and sulfate attack. Prevention and mitigation methods are provided for each factor.
Control of corrosion of underwater piles
This document discusses various methods for controlling corrosion of underwater piles. It describes how corrosion occurs and identifies different zones that piles are exposed to based on wetness and tidal patterns. Common protection methods include protective coatings, cathodic protection using sacrificial anodes, and application of fiber-reinforced polymer (FRP) composites. Protective coatings can include inorganic zinc primers, epoxy coatings, and polyurethane topcoats. Cathodic protection involves connecting anodes to the metal to redirect corrosion. FRP composites provide strength and chemical resistance for repairing damaged piles.
31-7-2021 Durability of concrete
Concrete durability is its ability to resist weathering, chemical attack, abrasion or other deterioration processes. A durable concrete is one that performs satisfactorily in its intended environment over its design service life. Factors that influence concrete durability include the environment/exposure conditions, water-cement ratio, constituent materials, compaction, curing and member shape/size. Common causes of lack of durability are physical effects like freezing/thawing and chemical effects like sulfate or chloride attack. Measures to improve durability include using low water-cement ratios, pozzolanic additions, proper compaction and cover over reinforcement.
Carbonation
Introduction to Carbonation. Detecting Carbonation. Factors affecting Carbonation. Measuring carbonation.
Corrosion on Concrete
Corrosion of steel reinforcement in concrete can occur through chemical or electrochemical reactions between the steel and its environment. This leads to deterioration of the steel and surrounding concrete. Corrosion occurs in two periods - an initiation period where the steel's protective layer is compromised, and a propagation period where corrosion spreads. Factors like concrete quality, chloride levels, cracks, and steel type influence corrosion rates. Corrosion causes issues like concrete cracking, spalling and bar snapping. Protection methods include coatings, cathodic protection, corrosion inhibitors, and improving concrete quality.
4.corrosion of reinforcement in concrete
The document discusses corrosion of reinforcement in concrete structures. It explains that corrosion occurs when the alkaline environment of concrete is lost due to carbonation or chloride ingress, exposing the steel reinforcement. Factors that influence corrosion include moisture, oxygen levels, concrete quality and cracks. Corrosion causes cracks and spalling of concrete as rust occupies more space. To prevent corrosion, sufficient concrete cover, good quality concrete with low water-cement ratio, proper compaction and curing should be used. Cement polymers and electroplating steel can also increase corrosion resistance.
Crain, Alexis Poster
This research aims to determine the chloride ion permeability in alkali-activated binder systems like fly ash, as a more sustainable alternative to ordinary Portland cement. The experimental process involved three phases: (1) characterizing chloride ion diffusion through non-steady state migration testing, (2) analyzing the pore structure through mercury intrusion porosimetry, and (3) evaluating chloride binding through electrical impedance spectroscopy. Preliminary results found that alkali-activated fly ash indicated increased impedance after migration testing, suggesting pore refinement and chloride binding occurred.
Applications of high performance lightweight concrete in a floating barge gate
This document discusses the application of high performance lightweight concrete (HPLC) in a floating concrete barge gate with a 100-year service life. HPLC was used due to its high strength, workability, low permeability and high durability properties which are essential for the long service life. The HPLC mix design incorporated lightweight aggregate, a low water-cement ratio of 0.38, and corrosion inhibitors to enhance chloride resistance. Chloride diffusion modeling predicted the concrete would resist chloride penetration for over 100 years. Additional protection at construction joints included PVC waterstops and hydrophilic resin injection to prevent water and chloride ingress.
More Related Content
What's hot
Corrosion Effects in Concrete
Corrosion of steel reinforcement in concrete is an electrochemical process that results in rust formation and expansion, which can crack and delaminate the concrete over time. The main causes of corrosion are chlorides and carbonation. Chlorides from deicing salts or seawater can penetrate the concrete and destroy the protective oxide layer on the steel. Carbonation occurs when carbon dioxide penetrates the concrete and raises its acidity, also damaging the protective layer. Common methods to protect reinforcement include using epoxy or zinc coatings on the steel, adding corrosion inhibitors to the concrete mix, or installing galvanic or impressed current anode systems that divert corrosion to the more easily corroded anode material.
Basics of Geopolymer concrete
This document summarizes research on geopolymer concrete as an alternative to traditional Portland cement concrete. Geopolymer concrete is made through a chemical reaction of aluminosilicate materials like fly ash with an alkaline solution, forming a three dimensional polymeric chain structure. It offers benefits over Portland cement like lower CO2 emissions in production, higher strength and durability, and the ability to utilize industrial waste materials. Some potential applications highlighted include use in coastal and cold weather construction for its chloride resistance, as well as airport runways and highways due to its heat resistance.
Service Life Prediction of RC Structure With Respect to Corrosion of Steel
This presentation discusses corrosion of steel reinforcement in reinforced concrete structures and its impact on service life. It covers the mechanisms of corrosion including carbonation-induced and chloride-induced corrosion. It also discusses various methods to control and prevent corrosion like using low water-cement ratios, supplementary cementitious materials, corrosion inhibitors, and protective coatings/catheathodic protection of the steel and coatings on the concrete. Maintaining proper concrete mix design, quality control, and reinforcement detailing can improve corrosion resistance and extend service life. Corrosion leads to cracking, loss of steel cross-section, bond degradation and reduced load capacity over time.
Concrete Corrosion of Reinforcing Steel
The document discusses corrosion of steel reinforcement in concrete and methods to minimize it. It describes how carbonation and chloride attacks can cause corrosion through electrochemical processes. Various techniques are presented to mitigate corrosion, including using epoxy coatings on rebar, adding fibers or memory alloys to concrete, using admixtures, hybrid fiber reinforced concrete, and fiber reinforced polymers applied after corrosion begins. Ongoing research gaps and a proposed future study are also mentioned.
A seminar report on control of corrosion on underwater piles
This document is a seminar report on controlling corrosion on underwater piles. It provides background on corrosion mechanisms of steel in seawater and defines zones of corrosion on steel piles. It then discusses corrosion management in three phases: assessment, physical assessment and remediation, and future monitoring. The report also describes various corrosion protection methods like protective coatings (inorganic zinc silicates primers, high build epoxy coatings, aliphatic polyurethane topcoats, zinc rich epoxy primers, non-skid deck coatings) and cathodic protection (suspension anodes, rod anodes). It gives examples of applying FRP composites on bridges to control corrosion.
2.chloride ingress in concrete
Chloride ingress is the penetration of chloride ions through pores into permeable concrete. The chloride ions come from salt containing chlorine. When chloride ions penetrate to the level of reinforcement in concrete and are in the presence of water and oxygen, they can destroy the protective iron oxide layer on the reinforcement and cause corrosion. Chloride ingress occurs through diffusion and absorption and is more likely when concrete has a high permeability from factors like a high water-cement ratio. Chloride ingress can cause expansion of concrete from corrosion, cracking as aggregates become unbonded, and chemical deterioration of reinforcing steel.
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..
The corrosion of reinforcement inside concrete is one of the factors affecting the performance of the structure. Here the presentation will enlighten you about its mechanism and other aspects.
Acid attack on concrete
This presentation gives an overview on different types of acid attacks on concrete. Mechanism of each attack is discussed with few case studies. Hope it is useful
Metakaolin
This document discusses metakaolin, which is produced by calcining kaolin clay between 650-800°C. It has pozzolanic properties and can partially replace cement in high strength concrete. Metakaolin increases the strength and durability of concrete by reacting with calcium hydroxide to produce additional calcium-silicate-hydrate gel. It improves the physical and chemical properties of concrete, leading to applications in infrastructure like bridges, dams, and buildings where high strength and durability are important.
Epoxy crack injection for concrete (the basics)
Epoxy injection offers a permanent repair for cracks (and delaminations) in concrete. The repair is structural, permanent and water-tight with the same lifespan as the surrounding concrete. It can be performed at temperatures as low 35°F, on cracks as narrow as 5 mils (5/1000”) and even underwater.
The cured epoxy restores the monolithic integrity of the concrete, protects the internal reinforcing steel from corrosion and is unaffected by water, chemicals and sunlight. University studies confirm that the repaired concrete matches the original strength of the uncracked concrete. A useful performance specification for the epoxy adhesive is ASTM C881, Type IV for load bearing (structural) applications. The cured high modulus epoxy generally exhibits more than 3 times the compressive strength and over 10 times the tensile strength of the surrounding concrete.
Typical structures repaired using epoxy injection include: parking decks, stadiums, concrete framed buildings, residential foundations, swimming pools, airport runways and taxiways, concrete bridge decks, floor cracking and delaminations in warehouses and manufacturing facilities, concrete pipe and tanks, concrete beams and piers and port facilities including docks, piers and pilings. Facilities where crack injection is often employed include water/sewage treatment plants, industrial sites, machinery foundations, and refrigerated and frozen food storage warehouses.
Specially trained contractors should be considered to properly perform crack repair using proper surface preparation procedures and positive displacement metering pumps to properly proportion and deliver the two component epoxy.
Benefits of Epoxy Injection
• Fast cure strength — up to 5,000 psi compressive yield in less than 5 hours,
• Vibration tolerant during cure — repairs can be made while structure is open,
• Unique concrete crack injection solutions for underwater, corrosive, large void (low exotherm) and other extreme exposures,
• O VOC concrete crack repair adhesives and seals,
• Can be used in temperatures as low as 35°F,
• Restores cracked concrete and structural members including beams and columns to original monolithic strength,
• Stops water leakage through foundations,
• Prevents corrosion of embedded reinforcing steel,
• Useful in secondary containment areas to prevent leaks and
• Unlike urethane chemical grouts, the epoxy crack repair is structural and permanent.
Fibre reinforced concrete
This presentation gives complete detail about the production, construction and applications with examples of Fibre Reinforced concrete.
SELF HEALING CONCRETE
Akif Perwez presented on self-healing concrete at a technical seminar. Bacteria-based self-healing concrete contains bacterial spores and nutrients that become activated when cracks form, allowing the bacteria to consume the nutrients and seal the cracks with limestone. Laboratory tests showed this concrete could self-heal cracks up to 0.8mm wide. Using this concrete could reduce costs by decreasing steel reinforcement needed and improve sustainability by reducing steel usage in waterproof applications. The presentation discussed how the bacteria-based self-healing process works, finding suitable bacteria that can survive in concrete, and full-scale testing of cracked concrete samples.
Carbonation of concrete
Carbonation is a chemical process where atmospheric carbon dioxide reacts with compounds in concrete, like calcium hydroxide, to form calcium carbonate, reducing the pH of concrete. This reaction exposes the reinforcing steel to corrosion. The depth of carbonation depends on factors like CO2 concentration, concrete pore structure, and relative humidity. Carbonation can be tested by using phenolphthalein solution, which changes color at pH 9.2, indicating the boundary between carbonated and uncarbonated concrete. Protective coatings can prevent further carbonation by providing a barrier to water and CO2 ingress.
Sulphate attack
Sulphate attack occurs when sulphates react with hardened cement paste, causing expansion and cracking of concrete. Soil sulphates do not severely damage concrete, but water sulphates can enter porous concrete and react with hydration products. This forms ettringite which increases in volume, disintegrating the concrete. Sulphate attack can be external from sulphates in groundwater penetrating concrete, or internal from sulphates in the original mix. Delayed ettringite formation is a type of internal sulphate attack where ettringite decomposes during curing then reforms, expanding and damaging the concrete.
Durability of concrete
The document discusses the durability of concrete and the factors that affect it. It defines durability as the ability of concrete to resist weathering, chemical attack, and abrasion while maintaining its desired properties. The main factors discussed are abrasion, biological factors, temperature effects, freezing and thawing, and various types of chemical attacks including carbonation, chloride attack, acid attack, and sulfate attack. Prevention and mitigation methods are provided for each factor.
Control of corrosion of underwater piles
This document discusses various methods for controlling corrosion of underwater piles. It describes how corrosion occurs and identifies different zones that piles are exposed to based on wetness and tidal patterns. Common protection methods include protective coatings, cathodic protection using sacrificial anodes, and application of fiber-reinforced polymer (FRP) composites. Protective coatings can include inorganic zinc primers, epoxy coatings, and polyurethane topcoats. Cathodic protection involves connecting anodes to the metal to redirect corrosion. FRP composites provide strength and chemical resistance for repairing damaged piles.
31-7-2021 Durability of concrete
Concrete durability is its ability to resist weathering, chemical attack, abrasion or other deterioration processes. A durable concrete is one that performs satisfactorily in its intended environment over its design service life. Factors that influence concrete durability include the environment/exposure conditions, water-cement ratio, constituent materials, compaction, curing and member shape/size. Common causes of lack of durability are physical effects like freezing/thawing and chemical effects like sulfate or chloride attack. Measures to improve durability include using low water-cement ratios, pozzolanic additions, proper compaction and cover over reinforcement.
Carbonation
Introduction to Carbonation. Detecting Carbonation. Factors affecting Carbonation. Measuring carbonation.
Corrosion on Concrete
Corrosion of steel reinforcement in concrete can occur through chemical or electrochemical reactions between the steel and its environment. This leads to deterioration of the steel and surrounding concrete. Corrosion occurs in two periods - an initiation period where the steel's protective layer is compromised, and a propagation period where corrosion spreads. Factors like concrete quality, chloride levels, cracks, and steel type influence corrosion rates. Corrosion causes issues like concrete cracking, spalling and bar snapping. Protection methods include coatings, cathodic protection, corrosion inhibitors, and improving concrete quality.
4.corrosion of reinforcement in concrete
The document discusses corrosion of reinforcement in concrete structures. It explains that corrosion occurs when the alkaline environment of concrete is lost due to carbonation or chloride ingress, exposing the steel reinforcement. Factors that influence corrosion include moisture, oxygen levels, concrete quality and cracks. Corrosion causes cracks and spalling of concrete as rust occupies more space. To prevent corrosion, sufficient concrete cover, good quality concrete with low water-cement ratio, proper compaction and curing should be used. Cement polymers and electroplating steel can also increase corrosion resistance.
What's hot (20)
Service Life Prediction of RC Structure With Respect to Corrosion of Steel
Service Life Prediction of RC Structure With Respect to Corrosion of Steel
A seminar report on control of corrosion on underwater piles
A seminar report on control of corrosion on underwater piles
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..
Similar to Electrochemical Extraction (ECE)
Crain, Alexis Poster
This research aims to determine the chloride ion permeability in alkali-activated binder systems like fly ash, as a more sustainable alternative to ordinary Portland cement. The experimental process involved three phases: (1) characterizing chloride ion diffusion through non-steady state migration testing, (2) analyzing the pore structure through mercury intrusion porosimetry, and (3) evaluating chloride binding through electrical impedance spectroscopy. Preliminary results found that alkali-activated fly ash indicated increased impedance after migration testing, suggesting pore refinement and chloride binding occurred.
Applications of high performance lightweight concrete in a floating barge gate
This document discusses the application of high performance lightweight concrete (HPLC) in a floating concrete barge gate with a 100-year service life. HPLC was used due to its high strength, workability, low permeability and high durability properties which are essential for the long service life. The HPLC mix design incorporated lightweight aggregate, a low water-cement ratio of 0.38, and corrosion inhibitors to enhance chloride resistance. Chloride diffusion modeling predicted the concrete would resist chloride penetration for over 100 years. Additional protection at construction joints included PVC waterstops and hydrophilic resin injection to prevent water and chloride ingress.
Transportation.mst.edu media research_transportation_documents_belarbi_aci_20...
This study investigated the effectiveness of CFRP sheets in repairing corrosion-damaged reinforced concrete (RC) columns. Small-scale and mid-scale RC columns were subjected to accelerated corrosion processes to simulate corrosion damage. Some columns were strengthened with CFRP sheets before or after corrosion conditioning. Testing showed that CFRP sheets decreased but did not prevent corrosion. CFRP wrapping confined spalling and cracking, improving compression capacity compared to unrepaired columns, but capacity was still reduced due to corrosion. Design guidelines were proposed accounting for strength reductions from corrosion.
IRJET - Comparative Study of Chloride Absorption in Pre-Conditioned Concrte C...
This document summarizes a research study that compares chloride absorption in pre-conditioned concrete cubes with different concrete mixtures. Seventy-two concrete cubes were prepared with six different mixtures that varied slump, water-cement ratio, and compressive strength. Cubes were pre-conditioned to be dry, fully saturated, or partially saturated. Cubes were then exposed to a 10% sodium chloride solution for 160 days. Chloride absorption was analyzed at various time intervals. Results showed that chloride absorption varied depending on pre-conditioning, mixture properties, and exposure duration. Absorption increased over time and was higher in dry pre-conditioned cubes compared to saturated cubes. Impregnated cubes generally had lower absorption than
Presentation of iqra malik
This document discusses corrosion in reinforced concrete structures, including its history and causes. It provides details on several bridge failures due to corrosion, including the collapse of the Mianus River bridge in 1983 and the Silver Bridge in 1967. The document also discusses experimental work on corrosion, including the effects of strain level, corrosion duration, and stress. It notes that carbonation and chloride ions can lead to corrosion by lowering the pH and attacking the steel. Permeability of concrete and thermal movement are identified as key causes of cracks in structures. Protection techniques like coatings and cathodic protection are also mentioned.
Behavior of carbon steel in simulated concrete pore solutions of air-entraine...
In Brazil, the air-entrained concrete has been extensively used as structural walls of housing units. Some of these units built recently in urban areas were inspected. Upon inspection, a significant variation of the potential corrosion measurement was obtained and reddish stains on the surface of the reinforcement were also observed, indicating active state of corrosion. Not always the concrete was fully carbonated and a chloride contamination was not detected. The occurrence of crevice corrosion was pointed as a possible cause of the premature corrosion as a non-uniform contact of the concrete with the reinforcement surface was detected.
In order to better understand the occurrence of premature corrosion of the inspected reinforcement, a complementary study was conducted at the laboratory to characterize air-entrained concretes and evaluate the behavior of steel bars immersed in solutions that simulate the water in the pores of these concrete and compare them to the pore solution of an ordinary Portland concrete.
The steel bars were evaluated under three conditions: blasted, corroded and galvanized. An intentional crevice was introduced on one of the bars. The behavior of the bars was monitored by visual examination and by electrochemical measurements. Finally, the corrosion rate was calculated. Tests on concrete specimens were also conducted to validate the results.
The characterization tests showed an inferior quality of the air-entrained concretes, having both high concentrations of pores, many of them fully interconnected. This justified the high deep carbonation observed in a short period of time and a variable electrical resistivity detected in the field.
The pore-solution immersion tests showed the higher corrosion susceptibility of metallic reinforcement in air-entrained concretes especially at the crevice areas. In the studied air-entrained concretes, the corrosion occurred preferentially under the sealant applied on the bar extremities. In one of them, corrosion was also observed on the free surface of the blasted bars. The corrosion was also observed in the air-entrained concrete specimens, confirming the tests solution results.
Recent Advancements in Piping industry and Piping materials.
A brief overview of the new technologies that are available for piping engineers to know the latest advancements in piping materials . As a chemical engineer, it is essential to know about the various piping systems and technologies associated with it, in order to have a better understanding of their project/ process/ installing/ commissioning of the plants/ refineries.
IRJET- Roughness Coefficient of Alkali Activated Mineral based Concrete C...
This document discusses a study that tested the roughness coefficient of alkali-activated mineral-based concrete composite pipes subjected to varying slopes. Geopolymer concrete pipes were cast and tested using a new setup that measured the roughness coefficient effectively. The test apparatus consisted of a discharge tank, steel stands, a valve assembly, hydraulic jack, LVDT, depth measuring gauge, and collecting tank. PVC pipes and conventional concrete pipes were first tested to validate the accuracy of the setup. Geopolymer concrete pipes with different fiber contents were then tested at various slopes measured by the LVDT. The time taken to fill the collecting tank was used to calculate the roughness coefficient value based on the Manning's formula for determining pipe discharge.
Concrete Specification and Methods of Quality Testing
This manuscript is about the concrete specification. The concrete specification testing is a process by which different tests are carried out such as compressive strength, carbonation depth, ASTM rapid chloride permeability, NDT chloride and initial surface absorption test (ISAT-10) to determine the quality and performance of the concrete in terms of strength, carbonation depth, chloride permeability and surface absorption.
case paper
This document summarizes a study on rehabilitation techniques for existing concrete structures. It discusses various repair methods and materials that can be used, including polymer modified mortar. Non-destructive tests were conducted on a sample structure to evaluate its condition. Based on the results, polymer modified mortar was selected for repairing columns due to its low cost, ease of application, and ability to extend the life of the building for 15-18 years at a lower cost than reconstruction. The study concludes that repairing existing structures using appropriate technologies and materials is more economical than demolition and aims to provide guidance on cost-effective rehabilitation.
Experimental Study: Determination of Concrete Reinforcement Conditions
Experimental Study: Determination of Concrete Reinforcement ConditionsKhalid Abdel Naser Abdel Rahim
This document summarizes an experimental study that determined concrete reinforcement conditions through four different tests: cover depth, concrete resistivity, 1/2-cell mapping, and chloride content. The tests were conducted on two reinforced concrete cubes with the same water-cement ratio and volume but different cover depth, resistivity, cell potential, and chloride content. The results of each test were analyzed to identify which cube had greater corrosion resistance and corrosion potential. The main causes of reinforcement corrosion in concrete are discussed as chloride attack, carbonation attack, and the presence of water and oxygen. The testing methods, equipment, merits, and limitations of each test are also described.IRJET - Corrosion of Steel Bars in Concrete Mixes Designed According to Diffe...
This document summarizes a study on the corrosion of steel bars in concrete mixes designed according to three different code recommendations (ECP 203-2017, ACI 318-2019, and BS 8500‐1:2015+A2:2019) and exposed to either pure water or sea water environments. 72 concrete cubes, cylinders, and rebar specimens were cast and tested for each mix design and curing environment. The study found that steel bars corroded less in pure water-cured concrete compared to sea water-cured concrete, across all three mix designs. Additionally, steel bars in ACI mix design concrete corroded less than the other two mixes in both curing environments. Compressive and splitting strengths were higher
PC Nov 2013 Internal Coating
1) Internally coating gas pipelines with epoxy coatings was developed in the 1950s to reduce corrosion and increase pipeline efficiency.
2) Epoxy coatings create a smooth inner surface that allows gas to flow more easily, reducing pressure drops and increasing flow rates. This can allow pipelines to transport more gas without increasing size.
3) Studies have found that epoxy coatings can increase a pipeline's gas transport capacity by 5-20%, reducing operating costs through lower compression needs over the lifetime of the pipeline.
Flexural Behaviour of Steel Fibers Reinforced High Strength Self Compacting C...
Flexural Behaviour of Steel Fibers Reinforced High Strength Self Compacting C...International Journal of Engineering Inventions www.ijeijournal.com
The document describes an experimental study that evaluated the flexural behavior of steel fiber reinforced high strength self-compacting concrete slabs. Six concrete slabs were tested with varying concrete types (ordinary, self-compacting, high strength self-compacting) and steel fiber volume fractions (0%, 0.75%, 1.5%). Test results found that using self-compacting concrete and adding steel fibers improved flexural resistance and led to more ductile failure. The high strength self-compacting concrete slab with 1.5% steel fibers showed the highest ultimate load capacity, an 18.8% increase over the non-fiber slab. A finite element analysis was able to reasonably model the slab test results.mahfooz_pulsed electrodeposition technology
The document discusses pulsed electrodeposition technology. It describes pulsed electrodeposition as a unique non-line-of-sight electrolytic deposition technique that uses modulated currents to obtain wear and corrosion resistant nanocrystalline coatings. Key factors that affect pulsed electrodeposition include pulse amplitude, width, and the use of heated baths. The technique has applications in corrosion resistance coatings for automobiles and wear resistance coatings for industrial tools and machinery. Recent research has focused on developing nanocomposite coatings for hard chrome replacement.
A Review On Strengthening Of RCC Square Columns with Reinforced Concrete Jack...
This document reviews strengthening of reinforced concrete square columns with reinforced concrete jacketing. It discusses how RC jacketing leads to uniformly increased strength and stiffness of columns. The durability of the original column is also improved with RC jacketing compared to other techniques. The review examines factors that influence the bond between the column and jacket, such as surface preparation, dowel bars, and transverse reinforcement. It concludes that RC jacketing is an effective and economical retrofitting technique that increases load capacity and improves structural performance of columns.
Abstracts of publications in ppc whilst affiliated with sask power
1) The document summarizes 5 journal publications by Emmanuel K. Quagraine related to power plant chemistry while affiliated with SaskPower.
2) The publications provide evidence that chlorinated compounds can ingress into power plant condensers in gaseous form through weak seals or porous brass tubesheets, causing chloride contamination issues. Regression models were able to confirm this hypothesis.
3) One publication evaluates using a biologically active carbon filter in series with a granular activated carbon filter for removing organics in boiler makeup water, finding over 80% removal with the two filters working synergistically.
Corrosion of steel reinforcement in concrete .ppt
This document discusses corrosion of steel reinforcement in concrete. It outlines the mechanisms of corrosion including factors that affect the passivity of steel like chloride ingress and carbonation. These can lead to the formation of corrosion cells. It also discusses methods to control corrosion like using low permeability concrete mixes, limiting chloride contamination, adequate concrete cover, and protective coatings.
Copy of Steel Corrosion.ppt
This document discusses corrosion of steel reinforcement in concrete. It outlines the mechanisms of corrosion including factors that affect the passivity of steel like chloride ingress and carbonation. These can lead to the formation of corrosion cells. It also discusses methods to control corrosion through the use of low permeability concrete mixes, limiting chloride contamination, adequate concrete cover, and protective coatings.
Seminar1.pptx
corrosion in rcc, prevention, control, effects, latest studies on corrosion, Although reinforced concrete structures are able to withstand towards a variety of adverse environmental conditions, reinforcement corrosion could lead to concrete structure deterioration. The present study examines four different ways of using corrosion inhibitors against pitting corrosion. In particular, it was investigated the chloride penetration resistance of reinforced cement mortars using corrosion inhibitor applied in three different, The corrosion behavior of the specimens was evaluated by electrochemical methods such as Linear Polarization Resistance and Half-cell Potential Resistance. In addition, the mass loss of steel rebars against time of partially immersion in sodium chloride (NaCl) solution was carried out in the lab. The experimental results showed that the corrosion systems examined in the study provide anticorrosion protection on steel rebars against chlorides comparing with the reference group.
Similar to Electrochemical Extraction (ECE) (20)
Applications of high performance lightweight concrete in a floating barge gate
Applications of high performance lightweight concrete in a floating barge gate
Transportation.mst.edu media research_transportation_documents_belarbi_aci_20...
Transportation.mst.edu media research_transportation_documents_belarbi_aci_20...
IRJET - Comparative Study of Chloride Absorption in Pre-Conditioned Concrte C...
IRJET - Comparative Study of Chloride Absorption in Pre-Conditioned Concrte C...
Behavior of carbon steel in simulated concrete pore solutions of air-entraine...
Behavior of carbon steel in simulated concrete pore solutions of air-entraine...
Recent Advancements in Piping industry and Piping materials.
Recent Advancements in Piping industry and Piping materials.
IRJET- Roughness Coefficient of Alkali Activated Mineral based Concrete C...
IRJET- Roughness Coefficient of Alkali Activated Mineral based Concrete C...
Concrete Specification and Methods of Quality Testing
Concrete Specification and Methods of Quality Testing
Experimental Study: Determination of Concrete Reinforcement Conditions
Experimental Study: Determination of Concrete Reinforcement Conditions
IRJET - Corrosion of Steel Bars in Concrete Mixes Designed According to Diffe...
IRJET - Corrosion of Steel Bars in Concrete Mixes Designed According to Diffe...
Flexural Behaviour of Steel Fibers Reinforced High Strength Self Compacting C...
Flexural Behaviour of Steel Fibers Reinforced High Strength Self Compacting C...
A Review On Strengthening Of RCC Square Columns with Reinforced Concrete Jack...
A Review On Strengthening Of RCC Square Columns with Reinforced Concrete Jack...
Abstracts of publications in ppc whilst affiliated with sask power
Abstracts of publications in ppc whilst affiliated with sask power
Electrochemical Extraction (ECE)
- 1. By EHAB HASUNA Electrochemical Chloride Extraction (ECE) By Ehab M.Hasuna
- 2. INTRODUCTION ECE PROCESS ADVANTAGES OF ECE DISADVATAGES OF ECE EXPERMINTAL STUDIES ON ECE CONCLUSION REFRENCESS
- 3. Electrochemical chloride extraction is a non- destructive treatment which : a) Extracts chloride ions from contaminated concrete. b) Reinstates the passivity of steel reinforcement. c) Produces a high pH environment. d) Re-establish the original properties and allows the concrete to continue in service without further concerns.
- 4. ECE accomplished by applying auxiliary anode and electrolyte to structure surface, and passing direct current between this anode and reinforcing steel which acts as a cathode. It aims to move chloride ions away from reinforcing steel and out of the concrete structure. The speed of chloride removal depends on the magnitude of the applied current. During ECE the electrochemical reaction occurring at the steel surface also increases the alkalinity of surrounding concrete through the generation of hydroxyl ions, which repassivates the steel by achieving chloride/hydroxyl ratios lower than initiation threshold level .
- 5. Nor cure chloride extraction process ECE SYSTEM
- 8. Chloride binding. Cement type. Alkalinity. Temperature. Aggregate. Current density. Rebar configuration.
- 9. Environmentally friendly: Major reduction of concrete breakout. Long term global protection: Provides effective treatment for the entire area of application. Proven technology: Long history and an excellent track record. Treatment completed in 4 to 8 weeks with no further maintenance. Temporary power supply can be used , no mains required.
- 10. New technology , few standards or specifications available yet. High charge density can cause some problems. Lifetime treatment not well defined yet. Require specialist knowledge.
- 11. ECE has gradually gained acceptance as an effective method for nondestructive treatment of concrete where chloride ingress has occurred to such an extent that may induce steel corrosion. The treatment usually utilizes a current density of 1-5 A/m2 (electrical field of less than 41V for safety reasons) for 4-8 weeks. Removed chloride can range between 40 and 60%.
- 12. In 1993, a few studies 22-24 funded by the Strategic Highway Research Program (SHRP) investigated the effectiveness of ECE as a rehabilitation measure for concrete bridge components, as well as the adverse side effects of elevated system current, such as increased concrete permeability, decreased steel- concrete bond, and cracking of the concrete. In a study by Minnesota Department of Transportation in 1999 25, although the ECE process reduced chloride levels in the treated structures by approximately 50%, several locations in the structures following ECE still had chloride concentrations in excess of the chloride threshold level.
- 13. Higher chloride extraction was obtained in non- carbonated concrete than in carbonated concrete irrespective of the configuration of the reinforcement system. Accumulations of alkali ions were greater in the non-carbonated concrete specimens.
- 14. According to some experimental studies it has been observed that concrete reinforced with multiple mats having the rebars directly placed over each other showed better chloride removal than those in which the rebars were displaced with respect to one another.
- 15. It was observed that circular columns containing spiral reinforcements showed better ECE performance than structures within planar surfaces. Practical studies implication is that supplemental ECE application may be more necessary in systems with planar surfaces than those with geometrically curved surfaces.
- 16. ECE can be effective method of removing chloride ions but during this process many side effects may occur inside the treatment concrete. .
- 17. Electrochemical realkalisation and chloride extraction treatments for reinforced concrete, CEN / TS 14038 -1. Standard Practice: Electrochemical realkalisation and chloride extraction treatments for reinforced concrete, NACE SP0107- 2007. Concrete society :Electrochemical realkalization and chloride extraction treatments for reinforced concrete, Part 2: Chloride extraction. J. Bennett, K.F. Fong, and T.J. Schue, Electrochemical Chloride Removal and Protection of Concrete Bridge Components: Field Trials, Strategic Highway Research Program, Washington DC, USA, Report #SHRP-S-669, 1993.