Mechanism of Deterioration of Concrete based Structures or Systems and Remedies | Adamas University (2022)

In the civil engineering field concrete is a construction materials is extensively used in construction work. Generally it is mixture of cement, fine aggregate (normally termed as sand) coarse aggregate (termed as stone chips or broken stones), water and some times admixture . It is used to develop or construct different type of structures or systems. These structures are generally two types , they are P.C.C and R.C.C. P.C.C stands for Plain Cement Concrete and R.C.C stands for Reinforced Cement Concrete. Now P.C.C structures are developed by mixing cement, sand, stone chips and water where admixtures are optional. In case of R.C.C along with P.C.C ingredients steel bars embedded into it. Performance of concrete in P.C.C and R.C.C is quite satisfactory from the strength point of view as well as many other aspects. One of the important performance of concrete in R.C.C is prevention of steel bars from external hazards. Both of the type of systems at early stage offers considerable resistance but as the time passes the degree of resistance of systems reduces. Thus resulting unsatisfactory performance of structural systems. Structural systems those are experiencing such type of adverse situations if not provided selective or necessary treatments. Most of the concrete structures or systems deteriorate through four different ways. Those are classified as –

  1. Chemical deterioration

This type of deterioration takes place due to chemical reaction at the concrete covers of R.C.C members. This reaction may take place in several ways –

(Video) Deterioration of Concrete & its Causes | Concrete technology (CT) lectures | Civil engineering

  1. Carbonation: Generally reinforced steel bars are surrounded by a particular grade of concrete. Harden concrete made up of calcium silicate gel and calcium hydroxide (Ca [OH]2). Ca [OH]2 ensure high alkaline nature of concrete to fight against corrosion and save steel from rust by creating a passive film around the steel bars. Due to this film, O2 and H2O fail to reach the main steel bars. Thus corrosion avoided. But if environment surrounding concrete covers, contains carbon dioxide( CO2) in air it may be vulnerable to RC members. CO2 in moisture enter in concrete cover through concrete pores. It reacts with Ca [OH]2 and produces calcium carbonate (CaCO3) and water (H2O). Thus reduces pH value of concrete and formation of acidic substance i.e, CaCO3. Due to this acidic substance passive film decays and open up the entry of O2 and H2O to main steel bars. This initiate the corrosion of steel and in tern resulting damage of RC structures.

Remedy – Application of different types of polymer based coating, stabilising primers on concrete surfaces offers protective barrier against concrete carbonation and slow down this adverse process. Adoption of epoxy coating on steel bars, safe guard the passive layer of steel bars also controls the carbonation process.

  1. Alkali-Aggregate Reaction : If aggregates containing reactive silica are used in concrete making, it is observed that alkaline solution reacts with silica present in aggregates and produces alkali-silica gel. The product volume is quite higher and bring out all the undesirable properties in concrete. Due to higher volume internal stresses generates and cracks develop in concrete structures or systems.

Remedy – Avoid use of reactive silica based aggregates in concrete making to control the Alkali-Aggregate Reaction.

(Video) PHYSICAL CAUSES OF DETERIORATION OF CONCRETE STRUCTURES|7SEM|MODULE1|RRS(17CV753)|SESSION 2

  1. Sulphate attack : It is also one of the important cause of concrete based structure’s deterioration. Sulphate may exists in nature e.g, in ocean water, ground water and industrial pollution etc in different soluble forms like calcium, sodium, magnesium etc. Sulphate attach may takes place by two reactions. When concrete structures come in contact with water contaminated by sulphates, then Ca [OH]2 , sodium based sulphate salt and water. Therefore produces gypsum thus reduces pH value due to loss of Ca [OH]2 from concrete. In the other way sulphate ion react with tri-calcium aluminate (C3A) and produces calcium sulphoaluminate hydrate (termed as ettringite) as major product. Both gypsum and ettringite posses higher volume expansion resulting internal stresses in concrete body. Finally concrete surfaces spall of from the actual concrete.

Remedy – Use of sulphur resisting cement, fly ash based cement, adequate compaction of concrete etc prevent this type of attack in concrete systems.

  1. Chlorine attack : Another adverse situation that happens to concrete when RC element’s constituents or environment contaminated by chlorine. Resulting corrosion of steel in RC structures or systems. If concrete come in contact of sea water or sea water used to produce concrete, higher chloride content in aggregate so on and so forth. Chlorides reached to passive layer surrounding steel bars and destroy it and then the bars are exposed fully to the environment. So corrosion initiates and reduces the cross sectional area of bars. Therefore tension carrying capacity of systems or structures reduces. While rusting occurs in bars, its volume immensely increases causing internal thrust in whole system and cracks generates that further accelerates corrosion process. Finally failure of structures or systems takes place.

Remedy – The best possible and easiest way to slow down this attack is to increase concrete cover, epoxy coating on steel bars and surface coating on concrete systems.

(Video) Deterioration of cementitious systems- Fire attack, abrasion and erosion

  1. Mechanical deterioration

Mechanical decay of concrete systems may occur through several ways like erosion, abrasion and cavitation. Concrete used to construct hydraulic structures are often subjected to the action of abrasion by fluid flow containing solid substances. Wearing of concrete surfaces due to this flow of fluid results erosion of systems termed as erosion. Sometimes movement of solid substances over concrete surfaces develops friction between each other. Some of the examples related to this type of friction are – acceleration and de-acceleration of moving vehicle’s wheels, movement of heavy machine over the industrial floors etc made up of concrete. Therefore considerable amount of material loss from system will occur. In the other way loss of materials from surface of concrete systems may occur as a result of irregular flow of fluid/water , change in the direction of flow creating vapour bubbles. This in turn show up as decay of concrete surfaces.

Remedy – Ensuring elimination of solid materials in fluid flow, treatment of concrete surfaces, use of higher grade of concrete can avoid and prevent this type of deterioration.

(Video) CHEMICAL CAUSES FOR DETERIORATION OF CONCRETE STRUCTURES|7 SEM|MODULE 1|RRS 17CV753

  1. Physical deterioration

This is a type of deterioration takes place mainly due to freezing and thawing. Locations where cold and hot weather conditions occurs frequently, in cold situation freshly produced concrete having adequate quantity of water free zed and converted into ice. Therefore volume of water increases and creates internal stresses into the system. While during in hot weather concrete thaws i.e, ice converted to water. Again freezing occurs and followed by thawing in repeated cycles. Thus resulting disruption of system and reduces the strength.

Remedy – Application of air entraining agents during concrete making dissipate internal stresses in concrete systems.

(Video) Deterioration of cementitious systems- frost attack, freeze-thaw and alkali-silica reaction

  1. Deterioration due to constructional errors

Constructional errors may occur through different ways those are given below :

  1. During production of concrete if water-cement ratio maintained is higher than specified value and adequate compaction is not achieved in concrete then it will show up in the form of tiny holes, honey combing etc over the concrete surfaces. This will not only interrupt the performance of concrete systems but the appearance of surfaces as well.
    Remedy – To avoid this error adequate care should be ensured during concrete making from the point of view of compaction and proportions of ingredients.
  2. Inappropriate placing of reinforcing steel bars in form work of RC members may also cause errors which finally become the reason of deterioration.
    Remedy – Placing of bars according to the codal guidelines help to avoid this type of error.
  3. Dislocation of form work and insufficient strength of temporary supports to form work during concrete placing resulting variation of dimensions of concrete structural members as well as violate design stipulations. As a result of which stress distribution throughout the members become non uniform and finally causes deterioration of systems.
    Remedy – Continuous supervision throughout the construction work ensure avoidance of this errors and deterioration.
  4. Also improper finishing and curing of concrete systems whether it is P.C.C or R.C.C, results deterioration of systems. Because if curing is not ensured properly, hydration reaction and production of calcium- silicate-hydrate (C-S-H) gel will not be adequate. Thus directly affects the performance of structures from the strength as well as durability point of view.
    Remedy – Based on the situation of construction sites (i.e, whether member is vertically or horizontally placed, temperature-atmospheric conditions and availability of resources etc.) finishing and curing (periodically) techniques should be adopted.

Further Studies :

(Video) Understanding Reparations: Session 2 - The Historical and Economic Perspective

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FAQs

What do you mean by deterioration explain the mechanism of deterioration in concrete structures? ›

Physical deterioration

Therefore volume of water increases and creates internal stresses into the system. While during in hot weather concrete thaws i.e, ice converted to water. Again freezing occurs and followed by thawing in repeated cycles. Thus resulting disruption of system and reduces the strength.

How is the deterioration process of concrete structure? ›

A concrete structure undergoing the deterioration shows the following indicative signs: cracking, spalling, abrasion, stains, erosion, deflection, and corrosion.

What is the mechanisms of deterioration? ›

Multiple deterioration mechanisms exist for concrete structures – chloride-induced corrosion – carbonation-induced corrosion – delayed ettringite formation – alkali-aggregate reaction – freeze-thaw degradation – others (ice abrasion, chemical attacks, etc.)

What are the causes of deterioration of concrete structures? ›

Causes: Chloride intrusion, oxygen-water exposure, corrosive chemical environment surrounding reinforcing steel, drop in alkalinity, improper placement or concrete coverage of steel reinforcement (rebar).

What are the effects of deterioration of concrete? ›

Deterioration typically results in: Cracking in the structural member – from corrosion, fatigue, chemical attack, construction defects, loading or repeated movement. Loss of strength in the structural material – from corrosion and fatigue of reinforcement; chemical or frost attack in concrete and fire or explosion.

What is concrete deterioration called? ›

Erosion is the deterioration of concrete surface as a result of particles in moving water scrubbing the surface. When concrete surface is exposed to the water-borne sand and gravel, the surface gets deteriorated by particles scrubbing against the surfaces. Flowing ice particles can also cause the problem.

What are the causes of deterioration? ›

Physically - induced deterioration is caused by freeze–thaw loads, non-uniform volume changes, temperature gradients, abrasion, erosion, or cavitation. Chemically-induced deterioration consists of carbonation, corrosion of steel reinforcement, sulfate and acid attacks, or alkali–aggregate reactions.

What are the causes of distress and deterioration of concrete? ›

Common causes of concrete distress and deterioration, including Accidental loadings, Chemical reactions, Construction errors, Corrosion of embedded metals, Design errors, Erosion, Freezing and thawing, Settlement and movement, Shrinkage, Temperature chang.

Which of the following comes under the mechanical mechanism of deterioration? ›

The main deterioration mechanisms that cause damages in the masonry fired bricks are (1) wetting–drying and (2) freezing–thawing mechanisms that can cause stress and deterioration, (3) salts attack that causes efflorescence and/or cracking of the material, (4) acid or basic attack, (5) the action of fire and, (6) the ...

What is the deterioration meaning? ›

: the action or process of becoming impaired or inferior in quality, functioning, or condition : the state of having deteriorated. rust deterioration. the deterioration of academic standards.

What do you mean by deterioration in civil engineering? ›

1 Definition of degradation. Structural deterioration (i.e., damage) is defined as any change to the material or the geometric properties affecting the structural performance (e.g., capacity).

What is the most common form of concrete deterioration? ›

  • Fig. Corrosion of reinforcing steel is.
  • the most common cause of concrete.
  • deterioration. ( 46080)

What are the preventive measures for concrete deterioration? ›

Topical sealants can be applied to further prevent concrete deterioration. Creto TopSeal is a hydrophobic, natural looking, topical sealant that is VOC free like all of the other Creto products. This combination of sealants can greatly reduce concrete deterioration and keep repair costs down on your property.

What are the causes of deterioration of materials? ›

In general, the main deterioration mechanisms include: (1) erosion, (2) volume change of the material and the volume changes of the material in pores, (3) dissolution of a material and the associated chemical changes, and (4) biological processes.

What are different types of damages to concrete? ›

Concrete Defects
  • Freeze-Thaw Effect: Concrete is very strong in compression but relatively weak in tension. ...
  • Chemical Attack: Chemical attack can occur because concrete is alkaline and chemically reactive. ...
  • Crazing: ...
  • Scaling: ...
  • Blisters: ...
  • Spalling: ...
  • Dusting: ...
  • Foreign Objects:

How do you control the deterioration of steel in concrete? ›

Corrosion of embedded metals in concrete can be greatly reduced by placing crack-free concrete with low permeability and sufficient concrete cover. Low-permeability concrete can be attained by decreasing the water to cementitious materials ratio of the concrete and the use of pozzolans and slag.

What are the main failures in concrete? ›

The 5 Main Types of Concrete Failure
  • MECHANICAL. Most mechanical failures occur because of physical impacts such as collisions. ...
  • CHEMICAL. ...
  • FIRE. ...
  • STRAY CURRENTS. ...
  • CORROSION.

What are the 4 types of structural failure? ›

Compressive, tensile, bending and buckling are the basic types of structural failure for construction elements.

Which is the major factor causing deterioration of a structure? ›

(i) Atmospheric moisture: Atmospheric moisture is regarded as the principal-agent causing the deterioration of the structures. Moisture is always present in the atmosphere and when the surface temperature falls, condensation can occur.

What is the most common symptoms of distress in a concrete structure? ›

Abstract:
  • 3.1. Looking for signs of distress.
  • 3.2. Categorization of common defects and signs of distress.
  • 3.3. Cracking in concrete.
  • 3.4. Volume change related cracks.
  • 3.5. Corrosion related cracks.
  • 3.6. Chemical reaction related cracks.
  • 3.7. Strength related cracks.
  • 3.8. Surface deterioration.
7 Jul 2015

What is climate related deterioration found in concrete? ›

The climate-related deterioration of concrete structures is mostly caused by the infiltration of deleterious substances from the environment, for example carbon dioxide and chloride, which causes reinforcement corrosion.

Which of the following is prone to reinforcement of corrosion Mcq? ›

Explanation: The steel is most liable to corrosion and hence the study of Steel corrosion is of Paramount importance.

What are the typical concrete damage caused by improper construction practice? ›

Problems with concrete include construction errors, disintegration, scaling, cracking, efflorescence, erosion, spalling, and popouts.

Does concrete deteriorate over time? ›

Modern concrete—used in everything from roads to buildings to bridges—can break down in as few as 50 years.

What is an example of deteriorate? ›

Deteriorate is defined as to make or become worse or lower in value or quality. An example of deteriorate is a child's mood going from happy to crying. An example of deteriorate is an orange going from ripe to moldy. To weaken or disintegrate; decay.

What is deterioration of building? ›

For silicate. building materials such as concrete, plasters, mortars, we use the term deterioration. Deterioration of concrete is a gradual and irreversible permanent erosion of its. basic properties leading to its disintegration. The study of concrete and building.

What is another word of deteriorate? ›

Some common synonyms of deterioration are decadence, decline, and degeneration. While all these words mean "the falling from a higher to a lower level in quality, character, or vitality," deterioration implies generally the impairment of value or usefulness.

Does concrete deteriorate with age? ›

As concrete cures, it shrinks, which can cause cracks. And as it reacts with water, concrete does something else – it creeps, or progressively deforms over time. This has been known for decades, and it is included in every concrete-related calculation used in construction projects, so it's not news.

Why is maintenance of structure important? ›

Routine maintenance of the structure is essential to keep it functional and protect it against early decay. A building is made of different parts in different locations and made of different materials. These are all susceptible to natural decay due to ageing.

What is need for repair of structure? ›

The need of structural repairs can arise from any of the following: Faulty design of the structure. Improper execution and bad workmanship. Extreme weathering and environmental conditions.

Does water deteriorate concrete? ›

Water can breakdown the materials that concrete is made of. Create mold and bacteria in the concrete, and cause concrete foundations to move and shift. All of these result in cracks in the concrete. Eventually damage to the concrete foundation of the home if not taken care of promptly.

Which of the given types of aggregate produces minimum voids in concrete but cause bond failure? ›

Explanation: Rounded aggregates: The aggregate with a rounded shape has the minimum percentage of voids ranging from 32 to 33%.

What are the 10 agents of deterioration? ›

CCI defines ten 'agents': dissociation, fire, incorrect relative humidity, incorrect temperature, light and ultraviolet light, pests, pollutants (or contaminants), physical forces, thieves and vandals (at times referred to as 'criminals'), and water.

What is chemical factor of deterioration? ›

Chemical deteriora- tion factors mainly include atmospheric pollutants that cause chemical reactions in correspondence with enhancing climate conditions. The effects of both indoor and outdoor pollutants on material degradation are described. Indoor pollutants include organic acids, sulphides, their compounds, etc.

What are the 4 factors affecting the environment? ›

Solution. The environment is affected by biotic and abiotic factors such as temperature, pressure, humidity, and organisms like human activity.

What is the deterioration meaning? ›

: the action or process of becoming impaired or inferior in quality, functioning, or condition : the state of having deteriorated. rust deterioration. the deterioration of academic standards.

What is concrete deterioration called? ›

Erosion is the deterioration of concrete surface as a result of particles in moving water scrubbing the surface. When concrete surface is exposed to the water-borne sand and gravel, the surface gets deteriorated by particles scrubbing against the surfaces. Flowing ice particles can also cause the problem.

What do you mean by deterioration in civil engineering? ›

1 Definition of degradation. Structural deterioration (i.e., damage) is defined as any change to the material or the geometric properties affecting the structural performance (e.g., capacity).

What is deterioration in building? ›

building materials such as concrete, plasters, mortars, we use the term deterioration. Deterioration of concrete is a gradual and irreversible permanent erosion of its. basic properties leading to its disintegration.

What are the causes of deterioration? ›

Physically - induced deterioration is caused by freeze–thaw loads, non-uniform volume changes, temperature gradients, abrasion, erosion, or cavitation. Chemically-induced deterioration consists of carbonation, corrosion of steel reinforcement, sulfate and acid attacks, or alkali–aggregate reactions.

What is an example of deteriorate? ›

Deteriorate is defined as to make or become worse or lower in value or quality. An example of deteriorate is a child's mood going from happy to crying. An example of deteriorate is an orange going from ripe to moldy. To weaken or disintegrate; decay.

What is another word of deteriorate? ›

Some common synonyms of deterioration are decadence, decline, and degeneration. While all these words mean "the falling from a higher to a lower level in quality, character, or vitality," deterioration implies generally the impairment of value or usefulness.

What is the most common form of concrete deterioration? ›

  • Fig. Corrosion of reinforcing steel is.
  • the most common cause of concrete.
  • deterioration. ( 46080)

What are the causes of distress and deterioration of concrete? ›

Common causes of concrete distress and deterioration, including Accidental loadings, Chemical reactions, Construction errors, Corrosion of embedded metals, Design errors, Erosion, Freezing and thawing, Settlement and movement, Shrinkage, Temperature chang.

How do you stop concrete from deteriorating? ›

Topical sealants can be applied to further prevent concrete deterioration. Creto TopSeal is a hydrophobic, natural looking, topical sealant that is VOC free like all of the other Creto products. This combination of sealants can greatly reduce concrete deterioration and keep repair costs down on your property.

What are four 4 causes of material deterioration? ›

In general, the main deterioration mechanisms include: (1) erosion, (2) volume change of the material and the volume changes of the material in pores, (3) dissolution of a material and the associated chemical changes, and (4) biological processes.

What are various human factors causing deterioration of building? ›

Following are the human factors causing the deterioration of the building: Use of poor construction materials. Poor workmanship during construction. Lack of supervision during construction.

What are different types of damages to concrete? ›

Concrete Defects
  • Freeze-Thaw Effect: Concrete is very strong in compression but relatively weak in tension. ...
  • Chemical Attack: Chemical attack can occur because concrete is alkaline and chemically reactive. ...
  • Crazing: ...
  • Scaling: ...
  • Blisters: ...
  • Spalling: ...
  • Dusting: ...
  • Foreign Objects:

What is deterioration in building materials? ›

Defects and deterioration:

[4]. Deterioration is a condition in which a building structure or its component has degenerated or become unstable [4].

Which of the following is a design error causing deterioration of concrete? ›

(2) Poor design details

Poor design detail may not lead to structural failure, but it can become the cause of deterioration of concrete.

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