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.
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.
This document discusses various types of chemical attacks that can occur on concrete, specifically chloride attack, sulphate attack, carbonation, and alkali-aggregate attack. It explains that chloride attack from permeable concrete is one of the leading causes of steel reinforcement corrosion in structures. The passive alkaline layer of concrete can degrade due to carbonation which reduces pH, allowing corrosion. Sulphate attack occurs when sulfates from soil, water, or industrial sources react with concrete compounds and expand in volume, cracking the concrete. Alkali-aggregate reaction involves chemical reactions between aggregate minerals and alkalis in concrete that can also cause cracking.
The document summarizes corrosion of steel reinforcement in concrete. It defines corrosion and describes the types as crevice and pitting corrosion. Chlorides are identified as the main cause as they can penetrate the protective oxide layer on the steel. Carbonation is also discussed as it lowers the pH and exposes the steel. The consequences of corrosion are outlined as rust formation which causes cracking, spalling and structural damage. Methods to prevent corrosion include coatings on the steel, using fly ash, galvanizing, and monitoring chlorides. Repair methods involve removing loose concrete, cleaning steel, applying protective coatings, and cement or epoxy patching.
It is the removal of one solid element from alloy by corrosion processes. Dealloying corrosion is also called
Dezincification
Selective Leaching
Parting
Service Life Prediction of RC StructureWith Respect to Corrosion of SteelNitesh Jha
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.
This document discusses corrosion of steel reinforcement in concrete. It outlines the mechanisms of corrosion, including how steel becomes passive in high pH concrete but can become depassivated by chlorides or carbonation. Chlorides from deicing salts, seawater, or contaminated aggregates are common sources of corrosion. Corrosion causes cracking and deterioration of concrete structures like bridges and marine structures. Control methods focus on using low permeability concrete mixes with good cover to prevent ingress of chlorides and carbonation.
corrosion and protection of steel reinforced c...Emad Behdad
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.
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.
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.
This document discusses various types of chemical attacks that can occur on concrete, specifically chloride attack, sulphate attack, carbonation, and alkali-aggregate attack. It explains that chloride attack from permeable concrete is one of the leading causes of steel reinforcement corrosion in structures. The passive alkaline layer of concrete can degrade due to carbonation which reduces pH, allowing corrosion. Sulphate attack occurs when sulfates from soil, water, or industrial sources react with concrete compounds and expand in volume, cracking the concrete. Alkali-aggregate reaction involves chemical reactions between aggregate minerals and alkalis in concrete that can also cause cracking.
The document summarizes corrosion of steel reinforcement in concrete. It defines corrosion and describes the types as crevice and pitting corrosion. Chlorides are identified as the main cause as they can penetrate the protective oxide layer on the steel. Carbonation is also discussed as it lowers the pH and exposes the steel. The consequences of corrosion are outlined as rust formation which causes cracking, spalling and structural damage. Methods to prevent corrosion include coatings on the steel, using fly ash, galvanizing, and monitoring chlorides. Repair methods involve removing loose concrete, cleaning steel, applying protective coatings, and cement or epoxy patching.
It is the removal of one solid element from alloy by corrosion processes. Dealloying corrosion is also called
Dezincification
Selective Leaching
Parting
Service Life Prediction of RC StructureWith Respect to Corrosion of SteelNitesh Jha
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.
This document discusses corrosion of steel reinforcement in concrete. It outlines the mechanisms of corrosion, including how steel becomes passive in high pH concrete but can become depassivated by chlorides or carbonation. Chlorides from deicing salts, seawater, or contaminated aggregates are common sources of corrosion. Corrosion causes cracking and deterioration of concrete structures like bridges and marine structures. Control methods focus on using low permeability concrete mixes with good cover to prevent ingress of chlorides and carbonation.
corrosion and protection of steel reinforced c...Emad Behdad
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.
Selective leaching, also called de-alloying or de-metalification, refers to the selective removal of one element from an alloy by corrosion processes. A common example is the dezincification of brass, where zinc is selectively removed leaving a porous copper structure. There are three steps in the mechanism of dezincification: (1) dissolution of the entire alloy, (2) replating of the more noble metal (copper), and (3) leaching away of the active metal (zinc). Dezincification can occur uniformly or in localized plugs and is caused by water containing sulfur, carbon dioxide, and oxygen. Prevention methods include using less susceptible alloys, adding inhibitors like tin
The document discusses corrosion of steel and methods for corrosion protection. It first covers the causes and types of corrosion including atmospheric corrosion. It then describes some basic methods for corrosion control like coatings, alloying metals, and galvanizing. Organic coatings and passive rust coatings are highlighted as major protective methods. The document also discusses research on corrosion prevention techniques like coatings, galvanizing, and alloying metals with corrosion resistant elements. It notes that corrosion costs the US billions annually and degrades coatings over time through processes like blistering and undermining. Finally, it summarizes some conclusions that coatings, galvanizing, and alloying can effectively prevent corrosion when used appropriately.
Corrosion is one of the leading causes of premature spring failure. There are two main failure mechanisms: fatigue and embrittlement. Corrosion can significantly reduce a spring's fatigue life by facilitating crack initiation and propagation. The frequency of cyclic loading also affects corrosion fatigue behavior, with lower frequencies reducing fatigue strength. To prevent corrosion-related failures, material selection, fabrication processes, and protective coatings must be optimized based on the application environment. Proper diagnosis of corrosion mechanisms helps improve mitigation strategies.
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.
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.
Rishabh Sharma's presentation discusses erosion corrosion, which is an increase in corrosion caused by a high relative velocity between a corrosive environment and a metal surface. It involves both chemical corrosion and mechanical wear as corroded metal is removed. The mechanisms are not fully understood but involve turbulent flow, suspended solids, and gas/liquid interactions. Erosion corrosion is more severe for softer metals and in equipment exposed to high velocities, turbulence, and mass transfer. Examples include pipes, valves, pumps and turbine blades. The presentation covers factors like pH, velocity, material choice, and surface films that influence erosion corrosion rates and provides prevention methods like design changes, environment modifications, material selection, and coatings.
The document discusses various types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking, intergranular corrosion, dealloying, and erosion corrosion. It also examines factors that influence corrosion such as the nature of the metal, temperature, moisture, pH, and impurities in the environment. Finally, it reviews methods to control corrosion including material selection, coatings, cathodic protection, and design considerations.
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..Rushikesh Katkar
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.
This document summarizes a review on corrosion of steel reinforcement in concrete structures. It discusses the two main causes of corrosion as the breakdown of the steel's passive film by chloride ions or carbonation reducing the concrete's alkalinity. Factors that affect corrosion rates are also examined, such as concrete permeability, moisture levels, and chloride concentrations. Monitoring methods like half-cell potential testing are described that can detect corrosion probability. Prevention techniques include using epoxy-coated rebar, fly ash concrete, corrosion inhibitors, or electrochemical extraction of chlorides. The formation of cracks from corrosion product expansion is also addressed.
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
This document provides a review of reinforcement corrosion in reinforced concrete (RC) structures. It discusses the mechanism of corrosion, including the electrochemical process where steel acts as the anode and concrete acts as the cathode. It also outlines various parameters that affect the corrosion rate, such as the presence of impurities, electrolytes like chlorides, and the position of metals in the galvanic series. The document describes different types of corrosion including pitting corrosion, general corrosion, and macro-cell corrosion. It explains how these types of corrosion negatively impact RC structures by causing cracking, delamination, and spalling of the concrete cover.
INHIBITION OF CO2 CORROSION BY FORMATE FLUIDS IN HIGH TEMPERATURE ENVIRONMENTS John Downs
Presentation to the Royal Society of Chemistry's "Chemicals in the Oilfield" conference, November 2005
The paper describes how formate brines protect steels against CO2 corrosion. It also shows the results of stress corrosion cracking tests on CRA steel samples exposed to high-density completion brines containing oxygen at 160 deg C. The 13Cr, 22Cr and 25Cr steels all cracked in the presence of calcium bromide brine containing oxygen.
The document summarizes corrosion of steel in concrete. It discusses the common corrosion processes like pitting and crevice corrosion. The main causes of corrosion are chloride ions and carbonation, which can lower the alkalinity of the concrete and expose the steel. It also outlines prevention methods like using epoxy coatings, fly ash, and cathodic protection to protect the steel reinforcement and prevent corrosion.
This document discusses different types of chemical attacks on concrete, including sulfate attack, sea water attack, and acid attack. Sulfate attack occurs when sulfates react with hydrated lime and calcium aluminate in concrete, forming ettringite and gypsum that cause cracking. Sea water attack involves corrosion of steel reinforcement due to chlorides as well as chemical and physical deterioration. Acid attack, which can be caused by acid rain, sewage, or industrial sources, dissolves calcium compounds in concrete and weakens its structure over time. Proper concrete mix design and coatings can improve resistance to chemical deterioration.
Corrosion inhibitors are chemical substances that minimize or prevent corrosion when added in small concentrations to an environment. They work by forming protective films on metal surfaces or reacting with corrosive components. Inhibitors can be inorganic, like chromates and nitrites, or organic compounds. They are applied through continuous injection, batch treatment, or squeeze treatment. The efficiency of an inhibitor depends on its concentration and ability to form protective barrier films on metals. Scavengers like hydrazine and sodium sulfite are also used to remove oxygen which promotes corrosion. Inhibitors find applications in various industries like petroleum, packaging, sour gas, and cooling systems.
This document discusses various methods for protecting metals from corrosion. It first defines corrosion as the deterioration of materials through chemical interaction with the environment. It then explains that oxygen, humidity, and chemical salts are common causes of corrosion. The document goes on to describe several protection methods, including barrier protection using paints, oils, or electroplating; sacrificial protection using more reactive metals; and cathodic protection of underground pipes using more electropositive anodes.
This document discusses hydrogen embrittlement, which is the loss of ductility in a material caused by hydrogen absorption. It can occur in body-centered cubic and hexagonal close-packed metals when as little as 0.0001% hydrogen is absorbed. Hydrogen is introduced through processes like corrosion and welding. It causes increased strain rate sensitivity and susceptibility to delayed fracture. Several mechanisms are proposed to explain how hydrogen causes embrittlement, including hydride formation and reducing decohesion strength. Prevention techniques include reducing corrosion, using cleaner steels, baking to remove hydrogen, proper welding practices, and alloying to reduce hydrogen diffusion.
IRJET - Comparative Study of Chloride Absorption in Pre-Conditioned Concrte C...IRJET Journal
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
Selective leaching, also called de-alloying or de-metalification, refers to the selective removal of one element from an alloy by corrosion processes. A common example is the dezincification of brass, where zinc is selectively removed leaving a porous copper structure. There are three steps in the mechanism of dezincification: (1) dissolution of the entire alloy, (2) replating of the more noble metal (copper), and (3) leaching away of the active metal (zinc). Dezincification can occur uniformly or in localized plugs and is caused by water containing sulfur, carbon dioxide, and oxygen. Prevention methods include using less susceptible alloys, adding inhibitors like tin
The document discusses corrosion of steel and methods for corrosion protection. It first covers the causes and types of corrosion including atmospheric corrosion. It then describes some basic methods for corrosion control like coatings, alloying metals, and galvanizing. Organic coatings and passive rust coatings are highlighted as major protective methods. The document also discusses research on corrosion prevention techniques like coatings, galvanizing, and alloying metals with corrosion resistant elements. It notes that corrosion costs the US billions annually and degrades coatings over time through processes like blistering and undermining. Finally, it summarizes some conclusions that coatings, galvanizing, and alloying can effectively prevent corrosion when used appropriately.
Corrosion is one of the leading causes of premature spring failure. There are two main failure mechanisms: fatigue and embrittlement. Corrosion can significantly reduce a spring's fatigue life by facilitating crack initiation and propagation. The frequency of cyclic loading also affects corrosion fatigue behavior, with lower frequencies reducing fatigue strength. To prevent corrosion-related failures, material selection, fabrication processes, and protective coatings must be optimized based on the application environment. Proper diagnosis of corrosion mechanisms helps improve mitigation strategies.
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.
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.
Rishabh Sharma's presentation discusses erosion corrosion, which is an increase in corrosion caused by a high relative velocity between a corrosive environment and a metal surface. It involves both chemical corrosion and mechanical wear as corroded metal is removed. The mechanisms are not fully understood but involve turbulent flow, suspended solids, and gas/liquid interactions. Erosion corrosion is more severe for softer metals and in equipment exposed to high velocities, turbulence, and mass transfer. Examples include pipes, valves, pumps and turbine blades. The presentation covers factors like pH, velocity, material choice, and surface films that influence erosion corrosion rates and provides prevention methods like design changes, environment modifications, material selection, and coatings.
The document discusses various types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking, intergranular corrosion, dealloying, and erosion corrosion. It also examines factors that influence corrosion such as the nature of the metal, temperature, moisture, pH, and impurities in the environment. Finally, it reviews methods to control corrosion including material selection, coatings, cathodic protection, and design considerations.
Corrosion of Reinforcement, Carbonation Of Concrete and It's Determination. ..Rushikesh Katkar
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.
This document summarizes a review on corrosion of steel reinforcement in concrete structures. It discusses the two main causes of corrosion as the breakdown of the steel's passive film by chloride ions or carbonation reducing the concrete's alkalinity. Factors that affect corrosion rates are also examined, such as concrete permeability, moisture levels, and chloride concentrations. Monitoring methods like half-cell potential testing are described that can detect corrosion probability. Prevention techniques include using epoxy-coated rebar, fly ash concrete, corrosion inhibitors, or electrochemical extraction of chlorides. The formation of cracks from corrosion product expansion is also addressed.
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
This document provides a review of reinforcement corrosion in reinforced concrete (RC) structures. It discusses the mechanism of corrosion, including the electrochemical process where steel acts as the anode and concrete acts as the cathode. It also outlines various parameters that affect the corrosion rate, such as the presence of impurities, electrolytes like chlorides, and the position of metals in the galvanic series. The document describes different types of corrosion including pitting corrosion, general corrosion, and macro-cell corrosion. It explains how these types of corrosion negatively impact RC structures by causing cracking, delamination, and spalling of the concrete cover.
INHIBITION OF CO2 CORROSION BY FORMATE FLUIDS IN HIGH TEMPERATURE ENVIRONMENTS John Downs
Presentation to the Royal Society of Chemistry's "Chemicals in the Oilfield" conference, November 2005
The paper describes how formate brines protect steels against CO2 corrosion. It also shows the results of stress corrosion cracking tests on CRA steel samples exposed to high-density completion brines containing oxygen at 160 deg C. The 13Cr, 22Cr and 25Cr steels all cracked in the presence of calcium bromide brine containing oxygen.
The document summarizes corrosion of steel in concrete. It discusses the common corrosion processes like pitting and crevice corrosion. The main causes of corrosion are chloride ions and carbonation, which can lower the alkalinity of the concrete and expose the steel. It also outlines prevention methods like using epoxy coatings, fly ash, and cathodic protection to protect the steel reinforcement and prevent corrosion.
This document discusses different types of chemical attacks on concrete, including sulfate attack, sea water attack, and acid attack. Sulfate attack occurs when sulfates react with hydrated lime and calcium aluminate in concrete, forming ettringite and gypsum that cause cracking. Sea water attack involves corrosion of steel reinforcement due to chlorides as well as chemical and physical deterioration. Acid attack, which can be caused by acid rain, sewage, or industrial sources, dissolves calcium compounds in concrete and weakens its structure over time. Proper concrete mix design and coatings can improve resistance to chemical deterioration.
Corrosion inhibitors are chemical substances that minimize or prevent corrosion when added in small concentrations to an environment. They work by forming protective films on metal surfaces or reacting with corrosive components. Inhibitors can be inorganic, like chromates and nitrites, or organic compounds. They are applied through continuous injection, batch treatment, or squeeze treatment. The efficiency of an inhibitor depends on its concentration and ability to form protective barrier films on metals. Scavengers like hydrazine and sodium sulfite are also used to remove oxygen which promotes corrosion. Inhibitors find applications in various industries like petroleum, packaging, sour gas, and cooling systems.
This document discusses various methods for protecting metals from corrosion. It first defines corrosion as the deterioration of materials through chemical interaction with the environment. It then explains that oxygen, humidity, and chemical salts are common causes of corrosion. The document goes on to describe several protection methods, including barrier protection using paints, oils, or electroplating; sacrificial protection using more reactive metals; and cathodic protection of underground pipes using more electropositive anodes.
This document discusses hydrogen embrittlement, which is the loss of ductility in a material caused by hydrogen absorption. It can occur in body-centered cubic and hexagonal close-packed metals when as little as 0.0001% hydrogen is absorbed. Hydrogen is introduced through processes like corrosion and welding. It causes increased strain rate sensitivity and susceptibility to delayed fracture. Several mechanisms are proposed to explain how hydrogen causes embrittlement, including hydride formation and reducing decohesion strength. Prevention techniques include reducing corrosion, using cleaner steels, baking to remove hydrogen, proper welding practices, and alloying to reduce hydrogen diffusion.
IRJET - Comparative Study of Chloride Absorption in Pre-Conditioned Concrte C...IRJET Journal
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
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.
A 36-year-old building collapsed in Bhiwandi, Thane, India at 3:40 am on September 21, 2020, killing 39 people. The building had 48 flats total, with 24 collapsing. The owner has been booked for culpable homicide and negligence. Building collapses are not uncommon in India, with over 13,000 structural collapses reported from 2010-2014 resulting in over 6,500 deaths. Concrete permeability and durability are important factors in preventing collapses. Permeability is influenced by water-cement ratio, compaction, and curing. The Indian code specifies minimum cement contents, water-cement ratios, and concrete grades required for different exposure conditions to ensure
IRJET - Correlation of Chloride Solution Absorption-Time in Pre-Condition...IRJET Journal
This document summarizes a research study that investigated chloride absorption in pre-conditioned dry concrete cubes (DCC) with different mixture designs. Seventy-two 100mm concrete cubes were cast with six mixtures that varied compressive strength, water-cement ratio, and slump. Cubes were submerged in 10% NaCl solution for 160 days and weighed periodically to determine chloride absorption. Results showed chloride absorption increased over time and was lower in solvent-based and water-based impregnated cubes compared to control DCC cubes. Chloride absorption also decreased with increasing compressive strength and was correlated to time using logarithmic expressions for all cube types. The study aimed to characterize the influence of dry conditions and impregnation
Pudlo is a concrete admixture that modifies the microstructure of concrete to improve its durability. It reduces permeability, absorption, and diffusion by densifying the cement paste and reducing porosity and pore size. This makes concrete virtually water-tight and prevents ingress of chloride ions, carbon dioxide, water and other chemicals that can cause corrosion of steel reinforcement or chemical attacks on concrete. Pudlo also autogenously heals microcracks to further improve concrete's resistance to permeation and durability against various degradation mechanisms like corrosion, sulfate attack, and acid attack. Case studies and third party testing show that Pudlo modified concrete outperforms standard concrete in real world exposure conditions and infrastructure projects.
1. The document discusses experimental and numerical investigations into chloride ingress in cracked concrete.
2. Controlled cracking was introduced using a modified wedge splitting test, and chloride mapping was performed using Laser-induced Breakdown Spectroscopy (LIBS).
3. Numerical modeling was also used to model chloride ingress, and can provide insight into complex phenomena like corrosion-induced cracking over long time periods.
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.
Corrosion of steel reinforcement in concrete .pptAmanNasirMujawar
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.
The document discusses repair and rehabilitation of concrete structures. It describes various causes of distress in concrete structures including structural causes, errors in design/construction, chemical reactions, and weathering. It then outlines the evaluation process for repair projects, including visual inspection, non-destructive testing, and laboratory testing to determine the extent of damage and appropriate repair methods. Specific causes of reinforcement corrosion like cracks, moisture, and concrete permeability are explained along with remedial measures.
This document discusses repair and rehabilitation of concrete structures. It covers causes of distress in concrete structures such as structural issues, design/construction errors, chemical reactions, and corrosion of reinforcement. It then describes evaluation procedures for repair projects, including visual inspection, non-destructive testing, and core extraction/testing. Specific causes of cracks in concrete like plastic shrinkage, thermal stresses, and inadequate reinforcement are also outlined. Finally, routing and sealing of cracks is discussed as a common remedial repair technique.
The document discusses a study that used ground penetrating radar (GPR) to develop models for estimating moisture and chloride content in concrete slabs. Concrete slab samples of varying moisture and chloride content were tested using GPR. The GPR wave attenuation correlated strongly with both the moisture and chloride levels. Two multiple regression models were developed that demonstrate a good correlation between GPR amplitude attenuation and the moisture and chloride concentrations in the concrete cover. The models can be used to estimate moisture and free chloride content in concrete, which provides useful information for assessing corrosion levels in reinforced concrete structures.
Effect of corroded reinforcement on structuresRini Dharva
This document discusses the effect of corroded reinforcement on the aging of reinforced concrete structures. It describes the basic process of corrosion through oxidation and reduction reactions. Corrosion occurs due to carbonation, which decreases the pH of concrete, or chloride ingress from deicing salts or seawater. The service life of a structure can be divided into an initiation period and a propagation period. As corrosion increases, the bond strength between steel reinforcement and concrete decreases. The document reviews two papers, one that proposes a model and condition rating system to estimate residual service life, and another that examines deterioration in Mumbai due to chloride content, sulfate content, and pH levels.
IRJET - Corrosion of Steel Bars in Concrete Mixes Designed According to Diffe...IRJET Journal
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
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.
(1) Common causes of concrete deterioration in Bangladesh include carbonation induced corrosion of steel bars, chloride induced corrosion, and sulfate attack.
(2) Carbonation occurs when carbon dioxide penetrates concrete and reacts with calcium hydroxide, lowering the pH and breaking down the protective layer on steel bars. Chlorides also break down this layer, while sulfates react with cement compounds and cause expansion cracking.
(3) To improve durability, concrete mixes should use a low water-cement ratio, adequate cover depth, and prevent penetration of carbon dioxide, chlorides and sulfates through impermeable concrete with a dense microstructure.
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.
The document discusses concrete durability strategies for the Rion-Antirion Bridge project in Greece, which requires concrete structures to withstand corrosion for 120 years in a marine environment. To achieve this, high-quality concrete was used with specifications exceeding contractual requirements. Testing showed the concrete had low chloride ion permeability and diffusion coefficients, validating its ability to prevent corrosion over 120 years. Strategies included using slag cement, low water-to-cement ratios, and increased concrete covers in more exposed zones to protect reinforcing steel from chlorides.
Permeability of concrete, chemical attack, acid attack, efflorescence, Corrosion in concrete. Thermal conductivity, thermal diffusivity, specific heat. Alkali Aggregate Reaction
Applications of high performance lightweight concrete in a floating barge gateUTHM
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.
Similar to Chloride penetration in marine environment (20)
Rainfall intensity duration frequency curve statistical analysis and modeling...bijceesjournal
Using data from 41 years in Patna’ India’ the study’s goal is to analyze the trends of how often it rains on a weekly, seasonal, and annual basis (1981−2020). First, utilizing the intensity-duration-frequency (IDF) curve and the relationship by statistically analyzing rainfall’ the historical rainfall data set for Patna’ India’ during a 41 year period (1981−2020), was evaluated for its quality. Changes in the hydrologic cycle as a result of increased greenhouse gas emissions are expected to induce variations in the intensity, length, and frequency of precipitation events. One strategy to lessen vulnerability is to quantify probable changes and adapt to them. Techniques such as log-normal, normal, and Gumbel are used (EV-I). Distributions were created with durations of 1, 2, 3, 6, and 24 h and return times of 2, 5, 10, 25, and 100 years. There were also mathematical correlations discovered between rainfall and recurrence interval.
Findings: Based on findings, the Gumbel approach produced the highest intensity values, whereas the other approaches produced values that were close to each other. The data indicates that 461.9 mm of rain fell during the monsoon season’s 301st week. However, it was found that the 29th week had the greatest average rainfall, 92.6 mm. With 952.6 mm on average, the monsoon season saw the highest rainfall. Calculations revealed that the yearly rainfall averaged 1171.1 mm. Using Weibull’s method, the study was subsequently expanded to examine rainfall distribution at different recurrence intervals of 2, 5, 10, and 25 years. Rainfall and recurrence interval mathematical correlations were also developed. Further regression analysis revealed that short wave irrigation, wind direction, wind speed, pressure, relative humidity, and temperature all had a substantial influence on rainfall.
Originality and value: The results of the rainfall IDF curves can provide useful information to policymakers in making appropriate decisions in managing and minimizing floods in the study area.
Applications of artificial Intelligence in Mechanical Engineering.pdfAtif Razi
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1. CHLORIDE PENETRATION IN
MARINE ENVIRONMENT
REPRESENTING BY
SAGAR G S (USN 4SM14CV054)
UNDER THE GUIDENCE OF
Prof .PRAMOD P.S
DEPARTEMENT OF CIVIL ENGENEERING
2. Contents
Introduction of marine environment
Chloride penetration
durability (steel get corroded and cracking )
Test to be assessed (chloride penetration)
factors affecting at chloride penetration
3. Contents
Limits of chloride content in concrete (as per IS: 456-2000 )
Concrete qualities under exposure conditions
Diffusion coefficient variation
Conclusion
Reference
4. INTRODUCTION OF MARINE
ENVIRONMENT
• The water containing some chemical salts , in salt water (sea
water)exposed to surrounding environment mainly affect on the
structures exposed such environment are considered as marine
environment.
• The behavior of concrete structures in marine environment has
shown that the main cause of distress is reinforcement corrosion
due to chloride attack.
5. CHLORIDE PENETRATION
• In marine environment ,the service life of reinforced concrete structures
depends mainly on deterioration due to reinforcement corrosion .
• Two stages can be considered in this mechanism ;
• The initiation period corresponding to the critical chloride penetration up
to the level of reinforcement and the propagation period related to the
reinforcement corrosion and its detrimental effects on the structure .
6. • The penetration occurs either through the capillary pores or through cracks by
permeation ,capillary suction and diffusion.
• Chloride is quantified by Fick’s second law.
• d C / d t=D(d^2C/dx^2 )
• Where C(x , t) is the chloride penetration at depth x at time t and D is the diffusion
coefficient .Since diffusion is only one of the transport mechanisms involved in
chloride penetration. D is not a “true” diffusion coefficient and should be
considered as an “apparent” diffusion coefficient
7. Durability of concrete get decreased by
following reasons
• steel get corroded in the reinforced concrete
• small cracking occurs in concrete
• exposure condition of structure in marine environment.
8. Test to be assess for chloride penetration
• The evaluation of chloride penetration was based on the assessment of
the chloride content in samples taken at various depths in successive
exposure periods.
• For each period dust samples for each 5mm depth increment were taken
in two adjacent holes using a 20mm diameter drilling tool.
• The samples were analysed to measure the total chloride content (acid
soluble chloride)using a chloride ion selective electrode.
9.
10.
11. Diffusion coefficient variation
• Diffusion coefficient varies for different concrete mixes
• DC varies with time
• DC varies with different exposure conditions
• DC level higher with higher humidity level.
13. Graph shows time dependence of the surface chloride
concentration
14.
15. Fig. 4 – Time evolution of the critical
chloride penetration for
the various concrete mixes and exposure
conditions.
16. Fig. 4 shows that a cover of 40 mm is not enough to guarantee a
service life of 50 years except in the atmospheric exposure
conditions and for good concrete quality.
Table 4 presents the values of the minimum cover for the various
concrete mixes and exposure conditions required to guaranteeing an
initiation period of 50 years. This period can be used as the service
life if the propagation phase is neglected.
17. Conclusion
• Chloride penetration in concrete structure is highly dependent on
concrete quality and exposure condition
• Diffusion coefficients vary significantly with the concrete quality
and exposure conditions and show a clear time dependence.
• Fick’s second law is a good simulation of the chloride
concentration.
18. Conclusion
• The results also show that small increases of concrete cover leads
to a significant increase in the service life. Small covers (< 40 mm)
are not appropriate for any exposure condition in marine
environment.
• The experimental results show that the diffusion coefficients and
the surface chloride content have at rong time dependence.
19. References
• Costa A and Appleton j (1999), “ Chloride Penetration into Concrete in Marine
Environment-Part 1:Main Parameters Affecting the Penetration”, Materials and
Structures.vol.218.pp.252-259.
• IS:456-2000 code of practice for Plain and Reinforcement Indian standards, New
Delhi .
• Senthil Kumar and Naveenraj (2014) “Estimation of Marine Salts Behavior
Around the Bridge Structures” Vol.03,No.4,November 2014.