What is the first step when repairing a damaged concrete structure?

A detailed assessment to determine the cause, nature, and extent of the damage, which includes visual inspection and Non-Destructive Testing (NDT) as per Clause 4.

What are common methods for repairing cracks?

Methods vary by crack type and include epoxy injection for structural bonding, routing and sealing with flexible sealants for non-structural cracks, and stitching for wider cracks (Clause 7).

What is concrete jacketing?

It is a strengthening technique where a new layer of reinforced concrete is added around an existing column or beam to increase its size and load-carrying capacity (Clause 9.2).

How is spalled concrete repaired?

By removing all unsound concrete, treating exposed reinforcement, and restoring the section using hand-applied mortars, form-and-pour techniques, or shotcreting (Clause 8).

IS 13640

: 1993

Guidelines for Repair and Rehabilitation of Concrete Structures - General Principles

CurrentSpecializedGuidelinesStructural Engineering · Demolition, Renovation and Repair of Structures

Download PDF BIS Portal Google

This standard provides general principles and a systematic approach for the repair and rehabilitation of existing concrete structures. It covers the assessment of damage, selection of appropriate repair materials and techniques, and methods for strengthening structurally deficient members.

Provides general principles and considerations for the repair and rehabilitation of concrete structures.

Quick Reference Values

Crack width for epoxy injection0.1 mm to 6 mm

Minimum compressive strength of repair mortarGenerally higher than parent concrete

Minimum bond strength of repair materialTypically > 1.5 N/mm²

Maximum chloride content in concrete (by mass of cement) for new construction0.4 kg/m³ (as per IS 456 ref.)

Practical Notes

Always diagnose the root cause of deterioration before selecting a repair method; a cosmetic repair without addressing the underlying issue (e.g., corrosion) will fail.

Ensure compatibility between the repair material and the parent concrete in terms of strength, modulus of elasticity, and thermal expansion to prevent premature failure of the repair.

Thorough surface preparation is the most critical step for achieving a durable bond. All loose/unsound material must be removed and the substrate cleaned.