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.