Principles of Concrete Repair & Protection

Introduction to Concrete repairs and protection

Concrete structures under go distress due  various factors during their service life. Identifying the distress, ascertaining the cause of distress and undertaking suitable remediation is essential for safe use of structure.

Reasons for distress.

• Accidental and unanticipated loadings.
• Design errors
• Weathering
• Poor construction practice.
• Corrosive environment.
• Fire damage
• Natural calamities viz. Earth quake, flood
• Use of defective materials

Approach to Concrete repairs

Condition assessment of structure.

• Assess the present condition of structure.
•  In situ parameters of materials.
• Conditions during construction.
•  Original design approach etc.

Consider various options available

• Do nothing.
•  Preserve current state.
•  Partial or total strengthening
• Suggest to demolition 

Selection or repair principle- Focus on main objective of repair.

• Concrete restoration.
• Structural strengthening.
• Protection against chemical ingress
• Others

Remediation methods

• Select remedial method based on the type of repair.
• Based on future service conditions.
• Based on the availability of products.

 Material selection.

• Based on minimum performance characteristics.
• Based on application methods selected.

Properties required for repair materials.

Shrinkage compensated.

Good bond strength with existing substrate.

Compatible Coefficient of thermal expansion with parent substrate.

Should possess sufficient alkalinity to protect steel embedded in concrete.

Low air and water permeability.

Resistance UV rays, heat and aggressive chemical attack wherever required.

Should be non hazardous.