Methods for Repairing Concrete Cracks
Focus: Epoxy Resin Injection
General Methods for Repairing Concrete Cracks
The method chosen for crack repair depends on the crack’s width, depth, activity, cause, and structural significance. Common techniques include:
Epoxy Resin Injection: For structural cracks where restoring monolithic action is necessary.
Polyurethane Injection: For watertightness, especially in active/leaking cracks.
Routing and Sealing: For non-structural surface cracks.
Stitching: Installing reinforcing steel across the crack.
Drilling and Plugging, Grouting: Often used for thick sections or to stop leakage.
Overlaying: Applying repair mortar or concrete over the cracked area.
Detailed Description: Crack Repair by Epoxy Resin Injection
Principle
Epoxy resin injection is a widely accepted method for the structural repair of narrow, dormant or slightly moving cracks in concrete. The process involves injecting a low-viscosity epoxy resin under pressure into cleaned cracks, which bonds the crack surfaces, effectively restoring the integrity and strength of the member.
Steps for Epoxy Injection Repair
Assessment and Preparation
Inspect the crack: Determine its depth, length, activity (moving or static), and cause.
Select proper resin formulation based on width and site conditions.
Surface Cleaning
Clean the crack and adjacent area from dust, oil, or loose materials using brushes, compressed air, or vacuum.
Sealing the Crack Surface
Seal the visible crack on the surface (except at injection ports) using an epoxy paste or other appropriate sealant to prevent leakage during injection.
Installing Injection Ports
Place ports (injection nipples) along the crack at regular intervals (typically 200–500 mm apart, depending on crack width and length) using the same sealing paste.
Mixing Epoxy Components
Mix the epoxy resin and hardener precisely according to the manufacturer’s instructions, ensuring homogeneity.
Injection
Starting from the lowest port (in vertical cracks) or one end (in horizontal cracks), inject the epoxy using a low-pressure pump or hand cartridge.
Continue injecting until the resin appears at the next port, then cap the first and proceed down the line.
Maintain steady pressure to ensure the resin fills the entire crack depth and length.
Curing
Allow the resin to cure as per the manufacturer’s recommended time.
Finishing
Remove surface ports, grind off excess epoxy, and restore the appearance as needed.
Inspection
Visually inspect the filled crack; non-destructive tests (e.g., ultrasonic pulse velocity) may be used to confirm the bond.
Advantages of Epoxy Resin Injection
Structural Restoration: Restores or even exceeds the original concrete’s strength and integrity.
Excellent Bonding: Outstanding adhesion to concrete and steel.
Durability: Resistant to many chemicals, moisture, and freeze-thaw.
Minimal Disruption: Repairs cracks without major section removal or replacement.
Penetration: Low-viscosity epoxies can fill very fine cracks (as small as 0.1 mm).
International Standards and Guidelines
ACI 224.1R: Causes, Evaluation and Repair of Cracks in Concrete Structures
ACI 503R: Guide to the Use of Epoxy Resins in Concrete
EN 1504-5: Products and systems for the protection and repair of concrete structures – Injection of cracks
ASTM C881: Standard Specification for Epoxy-Resin-Base Bonding Systems for Concrete
Equipment Required
Injection Pump: Low-pressure, high-precision pumps (manual, electric, or air-driven).
Epoxy Injection Packers/Ports/Nipples: To deliver resin into the crack at various points.
Cartridge Gun: For small repairs or short cracks.
Mixing Apparatus: For thorough blending of resin and hardener.
Surface Sealing Tools: Trowel, spatula, and epoxy paste/sealant.
Personal Protective Equipment (PPE): Safety glasses, gloves, and respirators as required.
Cleaning Equipment: Brushes, compressed air, or vacuum.
Professional Services
RBS-CONTECH (a specialized brand of Iran Concrete Clinic Group) has extensive experience in structural crack repair using advanced epoxy injection technology, following the latest international standards. With expert engineering teams, highly trained applicators, and modern equipment, RBS-CONTECH ensures long-lasting, high-quality repairs for all concrete structures.
Contact Information
Website: www.clinicbeton.com | www.rbs-contech.com
Email: clinicbeton.com@gmail.com
Phone: +982188070173, +982188584906
Mobile: +989102333497, +989120916271, +989120916272