
About
Concrete as material as high adaptability to satisfy many aspects functionally needs.
- Economy and maintenance
- Protection against fire and environment
- Resistance to cyclic loading
- Explosive resistance and better control over deflection
RCC structures extensively used for 50-60years. Deterioration of RCC is natural phenomenon. It needs to maintain the functional condition of the structure.
The distress in the concrete structures due to……
- Faulty designs and detailing
- Use of inferior and substandard materials
- Defects in construction
- Extreme loading conditions like severe Earthquakes or cyclonic storms.
- Lack of maintenance of the structure etc.
- Concrete structures that are deficient in quality will reflection its durability.
- Reinforcement corrosion will be faster and resistance to accidental fire will be reduced to a very great extent.
Defects (Cracking) in Concrete Structures
Before Concrete Hardens
- Plastic shrinkage cracks
- Plastic settlement cracks
- Cracks caused by movement
- Of the formwork
After Concrete Hardens
- Spalling
- Honeycombing
- Dusting
- Crazing
- Rain damage
- Rain damage
- Efflorescence
- Blistering
- Corrosion of reinforcing bars
Causes of Distress of Malfunctioning
The distress in old concrete structure could be due to one or more of the following reasons…
- Corrosion of the reinforcing bars due to ingress of corrosion promoting chemicals or due to carbonation of relatively porous concrete.
- Distress caused in the structure due to attack of chemicals in chemical factories.
- Crack formation due to alkali aggregate reaction, drying shrinkages or u earthquake damage or uneven settlements.
- Due to impact damage or due to continues erosion by water, liquid or solids.
- Due to the effect of aerobic and anaerobic bacteria in sewage disposal or treatment systems.
Fire damage of Structures
- Damage due to the use of poor quality ingredients, poor workmanship or improper design.
- Change of use of structures, such as
- Residential to commercial use
- Increased axial load beyond capacity of columns.
- Modification of structure for increasing space/accommodation.
- Structures may also require, major after their normal constructional lifespan.
- Sometimes buildings are required to be given a new architectural look to fit in the surrounding.
Structural malfunction
Causes
- Foundation settlement
- Weak and friable concrete
- Overloading
- Design deficiencies
Effects
- Structurally significant cracks
- Excessive deflection in beams
- Spalling and cracking of cover due to delimitation from the confined core.