- At a glance
- 1. Introduction
- 2. Repair System Framework
- 3. Relevant Codes & Standards (Consultant Quick Reference)
- 4. Decision Tree : System Wise
- 5. Decision Tree Failure Wise
- 6. Major Categories of Repair Solutions
- 7. Typical Application Process (EN 1504‑10)
- 8. QA/QC and Acceptance Tests
- 9. Notes for Consultants
- Disclaimer
- Feedback
How to use this page
- Use the table of contents to jump to classifications, selection matrices, and workflows.
- Start with the Selection Matrix to shortlist repair systems.
- Review Codes & Standards and the process flow before finalizing specs.
At a glance
- Typical defects: carbonation, corrosion‑induced spalling, chemical attack, impact damage, micro‑cracking
- System families: bonded mortars, flowable grouts, epoxy injections, polymer‑modified mortars, coatings
- Key standards: EN 1504, ASTM C881, ASTM C579/C580, ASTM C882, relevant IS codes
- Process anchors: diagnosis → prep → rebar treatment → bonding → application → curing → protection
1. Introduction
Concrete repair and protection systems are specialized solutions designed to restore structural integrity, durability, and service life of deteriorated concrete. Failures in concrete typically occur due to:
- Reinforcement corrosion (chloride ingress, carbonation)
- Chemical attack (sulfates, acids, COâ‚‚)
- Freeze–thaw damage
- Poor workmanship, cracks, leakage
- Overloading or vibration fatigue
A successful repair system is not just patching concrete. It is a complete rehabilitation cycle:
- Identify the cause →
- Arrest deterioration →
- Repair structural damage →
- Protect the repaired surface.
2. Repair System Framework
Step | Objective | Typical Material Category / References |
1. Assessment | Diagnose distress (visual, NDT, chloride, carbonation) | IS 13311, IS 516, EN 1504‑9 |
2. Preparation | Surface profiling, steel cleaning, removal of loose material | Hydro‑jetting, grit blasting |
3. Repair (Build‑back) | Replace lost section, restore profile, structural repair | Cementitious or epoxy mortars, microconcrete |
4. Protection | Shield from ingress of water, CO₂, chlorides | Acrylic, PU, anti‑carbonation coatings |
5. Corrosion Control | Arrest active corrosion, extend service life | Inhibitors, migratory inhibitors, galvanic anodes |
3. Relevant Codes & Standards (Consultant Quick Reference)
Standard | Description / Use |
IS 456: 2000 | Code of Practice for Plain and Reinforced Concrete. |
IS 516: 2018 | Methods of test for strength of concrete. |
IS 13311 (Part 1 & 2) | Non‑destructive testing — Ultrasonic Pulse Velocity and Rebound Hammer. |
IS 9013: 1978 | Method of making, curing and determining flexural strength. |
IS 9103: 2021 | Specification for admixtures for concrete. |
IS 14311: 1996 | Repair and rehabilitation of concrete structures — Guidelines. |
EN 1504 (Parts 1–10) | Comprehensive European standard for concrete repair and protection. |
ACI 562‑19 | Code requirements for assessment, repair and rehabilitation of concrete structures. |
ASTM C881 | Epoxy‑resin‑based bonding systems for concrete. |
ASTM C579 / C580 | Compressive and flexural strength testing for epoxy mortars and grouts. |
ASTM C882 | Bond strength test for repair materials. |
EN 1504‑2, EN 1504‑3, EN 1504‑4, EN 1504‑7, EN 1504‑9, EN 1504‑10 | Surface protection, structural and non‑structural repair, bonding, rebar protection, principles and execution. |
BS EN ISO 12696 | Cathodic protection of steel in concrete. |
ASTM D1653, ASTM D523 | Water vapour transmission and gloss for coating evaluations. |
4. Decision Tree : System Wise
System Category | Key Materials | Target Strength Range (MPa) | Primary Function | Standards |
Cementitious Repair | PMM, Microconcrete, Fast-setting Mortar | 25-60
| Section rebuild, patch repair | EN 1504-3 |
Epoxy Repair | Epoxy Mortar, Grout, Injection, Bonding Agent | 70-100 | Structural crack filling, bonding | ASTM C881 / EN 1504-4 |
Polymer Repair | SBR / Acrylic Mortar, PU Injection | 30-50 | Waterproof & flexible patch | IS 9103 / EN 1504-2 |
Structural Strengthening | CFRP, GFRP, RC Jacketing | — | Load upgrade, flexural/shear strengthening | ACI 440 / IS 15988 |
Protective Coatings | Acrylic, PU, Epoxy, Cementitious | — | Barrier, anti-carbonation, chemical resistance | EN 1504-2 |
Corrosion Control | MCI, Anodes, CP systems | — | Arrest corrosion, passive film formation | EN 1504-9 / ISO 12696 |
Grouting Systems | Cementitious, Epoxy, PU, Vinyl | 25–90 | Void filling, anchoring, leakage sealing | EN 1504-5 / ASTM C1107 |
5. Decision Tree Failure Wise
- Cracking in Concrete
Cracks are the most common visible form of distress. The solution depends on crack width, activity, and root cause.
Crack Type | Root Cause | Repair Strategy | System Category | Material Type | Relevant Standard | Expected Outcome |
Hairline (<0.3 mm) | Shrinkage / Thermal stress | Fill using flexible PMM | Cementitious Repair | Polymer Modified Mortar | EN 1504-3 (R2) | Surface sealed, breathable patch |
Structural (0.3–2 mm) | Overload / Settlement | Inject with low-viscosity epoxy | Epoxy Repair | Epoxy Injection Grout | EN 1504-5 / ASTM C881 | Restores monolithic continuity |
Active Movement Crack | Thermal movement / Expansion | Fill with PU injection (hydrophilic/hydrophobic) | Polymer Repair / Grouting | PU Injection Grout | EN 1504-5 | Watertight & flexible joint |
Random cracking in large section | Drying shrinkage / restraint | Overlay with microconcrete | Cementitious Repair | Shrinkage-compensated Microconcrete | EN 1504-3 (R4) | Homogeneous structural surfac |
- Spalling/ Delamination
Caused by rebar corrosion, poor cover, or freeze–thaw cycles.
Root Cause | Repair Strategy | System Category | Material Type | Key Step | Relevant Standard | Expected Outcome |
Rust-induced expansion | Remove loose cover + apply rebar passivator + rebuild | Polymer or Cementitious | SBR Modified Mortar / PMM | Rebar cleaning + bonding coat | EN 1504-7 / EN 1504-3 | Arrest corrosion + restore profile |
Poor compaction / Honeycombing | Cut out + form-and-pour | Cementitious Repair | Microconcrete | Formwork & fluid fill | BS EN 12190 | Solid monolithic restoration |
High chloride exposure | Patch + apply MCI or PU coating | Corrosion Control + Coating | MCI + PU Hybrid | Surface & internal barrier | EN 1504-9 | Long-term corrosion protection |
- Corrosion Control
Addresses active or potential steel corrosion within the concrete section.
Corrosion Type | Mechanism | Solution Type | System Category | Material Type | Relevant Standard | Outcome |
Chloride-induced | Marine / Coastal ingress | MCI spray or admixture | Corrosion Control | Migrating Corrosion Inhibitor | EN 1504-9 / ACI 222R | Stops anodic reaction |
Carbonation-induced | COâ‚‚ attack, reduced alkalinity | Anti-carbonation coating | Protective Coating | Acrylic / PU | EN 1504-2 | COâ‚‚ diffusion barrier |
Localized patch corrosion | Differential potentials | Galvanic protection | Corrosion Control | Zinc Sacrificial Anodes | EN ISO 12696 | Equalized rebar potentials |
- Structural Damage/ Load Deficiency
Structural upgrades or restoration for load-carrying members (beams, slabs, columns).
Distress | Cause | Remedial System | System Category | Material Type | Standards | Expected Outcome |
Flexural failure | Overloading / design deficit | CFRP sheet bonding | Structural Strengthening | CFRP Laminate | ACI 440 / IS 15988 | Increased flexural capacity |
Shear deficiency | Inadequate stirrups | CFRP wraps or GFRP mesh | Structural Strengthening | Fiber Wrap | EN 1504-4 | Increased shear capacity |
Column buckling | Axial overload | RC Jacketing | Cementitious + Steel | Microconcrete + Anchors | EN 1504-3 (R4) | Ductility & confinement |
Anchor pull-out | Insufficient embedment | Chemical / epoxy anchors | Epoxy Repair | Epoxy Resin Anchor | ASTM C881 | Safe load transfer |
- Surface Degradation/ Chemical Attack
Occurs in industrial plants, coastal zones, and sewage structures due to acids, sulfates, or chemical fumes.
Chemical Exposure | Repair / Protection | System Category | Material Type | Standard | Expected Performance |
Acidic environment (pH <5) | Epoxy coating | Protective Coating | 100% Solids Epoxy | EN 1504-2 / ASTM D543 | Resistant to acid vapors |
Sulfate-rich groundwater | PU coating / Cementitious barrier | Protective Coating | Aliphatic PU / Cementitious | IS 2645 / EN 1504-2 | Non-permeable barrier |
Coastal splash zones | Anti-carbonation + silane sealer | Protective Coating | Acrylic Hybrid + Silane | EN 1062-6 / EN 1504-2 | Prevents chloride ingress |
- Voids/ Anchor Grouting
When voids under base plates, machinery, or bearings need to be filled for load transfer.
Condition | Remedy | System Category | Material Type | Standard | Performance |
Static load (bridges, bearings) | Precision grouting | Grouting System | Non-shrink Cementitious Grout | EN 447 / ASTM C1107 | Flowable, high compressive strength |
Dynamic load / vibration | High-strength epoxy grout | Grouting System | Epoxy Grout | EN 445 / ASTM C881 | 70–90 MPa compressive |
Fine voids / cracks | Injection sealing | Grouting System | PU / Acrylic Grout | EN 1504-5 | Watertight sealing |
Soil voids under foundation | Microfine cement injection | Grouting System | Microfine Grout | EN 12715 | Ground stabilization |
- Leakages/ Water Ingress
Seen in basements, tanks, podium slabs, and retaining walls. Depends on source accessibility.
Leakage Type | Condition | Treatment | System Category | Material | Standard | Expected Result |
Dampness / slow seepage | Capillary ingress | Acrylic / Vinyl Acrylate injection | Grouting System | Low-viscosity resin | EN 1504-5 | Dampness sealed |
Running leakage | Active water ingress | PU hydrophilic foam injection | Polymer / Grouting | PU Foam | EN 1504-5 | Immediate sealing |
Inaccessible top (roof/basement) | Negative side only | Grid-based injection grouting | Grouting System | PU or Vinyl Acrylate | IS 14311 | Area sealed without demolition |
Masonry wall dampness | Rising damp / capillary | Breathable cementitious coating | Protective Coating | Crystalline or Osmotic Coating | EN 1504-2 | Vapor-permeable dry wall |
6. Major Categories of Repair Solutions
Cementitious Repair Systems
Cementitious Repair Systems
Epoxy Repair Systems
Epoxy Repair Systems
Polymer-Based Repair Systems
Polymer-Based Repair Systems
Structural Strengthening Systems
Structural Strengthening Systems
Protective Coatings
Protective Coatings
Corrosion Control Systems
Corrosion Control Systems
Grouting Systems
Grouting Systems
7. Typical Application Process (EN 1504‑10)
- Assessment and testing (chloride, carbonation, NDT)
- Preparation (remove weak concrete, clean rebar)
- Priming (bond coat using polymer‑modified slurry)
- Repair / rebuild (mortar, microconcrete, or epoxy)
- Curing (wet or membrane‑based)
- Protection (coating, inhibitor, or hydrophobic treatment)
8. QA/QC and Acceptance Tests
Inspection Parameter | Standard | Acceptance Criteria |
Pull-off adhesion | EN 1542 | ≥1.5 MPa |
Compressive strength | EN 12190 | 25–60 MPa |
COâ‚‚ diffusion resistance | EN 1062-6 | > ref. concrete |
Chloride permeability | ASTM C1202 | <1000 coulombs |
Crack bridging | EN 1062-7 | ≥0.3 mm at 23°C |
Rebar potential | ASTM C876 | <–250 mV (passive state) |
9. Notes for Consultants
- Select repair class based on structural criticality: R2 (non‑structural), R3 (moderate structural), R4 (full structural)
- Never apply an impermeable coating over damp, breathing concrete unless a vapour barrier is intended
- For marine, industrial, or ETP applications, include a corrosion inhibitor layer below the coating
- Ensure compatibility between repair mortar, substrate, and protective coating
- Maintain documentation: MTCs, site test reports, and EN 1504 compliance certificate
Disclaimer
SpecX is a neutral, standards‑aligned resource compiled from industry references and best practices. Always verify against project specifications and local codes before finalizing.