For pressure injection and gravity feed structural crack repair in horizontal concrete and masonry, ARDEX RA 142 seals and bonds hairline to fine cracks from 0.05mm to 3mm. This two-component, 100% solids epoxy adhesive has a super low viscosity that penetrates deep into fine fractures to restore structural integrity to interior and exterior slabs, walls, and timber members.
ARDEX RA 142 functions as a high-strength structural binder and adhesive. Its super low viscosity of 190 cps allows it to flow freely into narrow fissures where thicker epoxies cannot penetrate. When mixed with kiln-dried sand or aggregate, it serves as a high-strength epoxy resin mortar for concrete spall repairs and interior surface overlays. The solvent-free formulation cures to a highly rigid polymer, achieving a compressive strength of 70 MPa and a tensile strength of 50 MPa to reinstate load path continuity across sheared or fractured structural sections.
This structural epoxy is suitable for repairing dormant cracks in several configurations:
For gravity-feed crack repairs, cut a groove 3mm wide and at least 1mm deep along the crack using an abrasive or diamond blade. Wire brush the groove and blow out all dust, dirt, grease, and contaminants prior to pouring or injecting the epoxy.
For spall repairs, cut a clean vertical edge around the spall perimeter to a minimum depth of 20mm to prevent feathered edges. Chip out loose material, clean the cavity, and mix Part A and Part B at a 2:1 ratio by volume before mixing in aggregate. Apply at a maximum mortar thickness of 35mm per coat.
For vertical cracks, clean the surface, secure injection ports at 15cm to 30cm intervals using ARDEX RA 88 capping paste, and seal the entire crack face. Inject ARDEX RA 142 from the lowest port upward until material flows from the adjacent port. Keep the final port under pressure for 30 seconds to ensure complete filling.
Keep the dual cartridge upright during preparation to prevent leakage. Shake the cartridge for 1 minute, then stand it upright for 1 minute to allow air bubbles to rise. Load it into the dispenser and point it upward at a 45-degree angle. Remove the cap and plug, then dispense material into a waste container until both parts flow evenly. Insert the flow control port and nozzle, point upward at 45 degrees, and dispense 1 to 2 trigger pulls to prime the nozzle. If using a pneumatic dispenser, use an air pressure regulator limited to a maximum of 275 kPa (40 psi) to prevent plunger leakage.
No, ARDEX RA 142 is not designed for active cracks. It is formulated for dormant cracks in structures where the cause of cracking has been addressed and further movement is not expected.
ARDEX RA 142 is engineered for hairline to fine cracks, specifically those between 0.05mm and 3mm. Its low viscosity of 190 cps ensures deep penetration into these narrow defects.
This epoxy provides significant structural strength, achieving 70 MPa compressive and 50 MPa tensile strength after 7 days. This allows it to restore load-bearing capacity to cracked concrete members when used correctly.
No, ARDEX RA 142 is not designed to stop seeping or flowing water. While it can be applied in moist environments, all standing or flowing water must be stopped and removed before application for effective repair.
| Application | Key benefit | Primary trades |
|---|---|---|
| Gravity-feed horizontal crack repair (0.05mm - 3mm) | Deep penetration into hairline cracks and restoration of concrete's structural load-bearing capacity (70 MPa compressive strength). | Concrete repairers, Civil contractors |
| Pressure injection for vertical cracks (with ARDEX RA 88) | Ensures full crack void fill in vertical sections, restoring structural integrity and preventing further damage. | Structural engineers, Concrete repairers |
| Bonding hardened concrete to hardened concrete | Achieves a high-strength, permanent bond (11 MPa shear bond at 7 days) for concrete sections. | Concreters, Commercial builders |
| Epoxy mortar for spall repair (with aggregate) | Creates a durable, high-strength repair up to 35mm thick, resisting further deterioration. | Concrete maintenance, Remedial builders |
A successful repair starts with proper preparation. Ensure the concrete is sound, clean, and completely dry. New concrete must be cured for at least 28 days.
Use a wire brush to clean the crack surface. Blow out all dust, debris, and contaminants from within the crack using clean, oil-free compressed air. This step is critical for achieving a full structural bond.
For hairline cracks in horizontal slabs, consider using a grinder with a diamond blade to cut a V-groove. This creates a small reservoir, making it easier to gravity-feed the epoxy and ensuring a complete fill.
Proper cartridge preparation prevents mix issues and ensures consistent performance.
Place the 470mL cartridge into the dispenser gun. Remove the plastic cap and plug, then dispense a small amount of material into a disposable container until both Part A and Part B are flowing evenly.
Attach the static mixing nozzle to the cartridge. Dispense and discard the first 1-2 trigger pulls of material to ensure a perfectly mixed product from the start.
Select the application method based on the crack's orientation.
Slowly dispense the mixed epoxy directly into the prepared crack or V-groove. Allow the product's self-levelling properties to fill the void completely. Re-apply if necessary to ensure the crack is filled flush to the surface.
Securely attach injection ports along the crack and seal the crack face with Ardex RA 88 Capping Paste. Start injecting at the lowest port and continue until epoxy flows from the port above. Plug the first port and move to the next, repeating until the entire crack is filled.
Allow the repair to achieve full strength before proceeding.
ARDEX RA 142 is considered hazardous. Always refer to the Safety Data Sheet (SDS) before use.
Wear suitable gloves and eye/face protection to avoid skin and eye contact. Obtain special instructions before use.
Store in original unopened packaging in a dry place between 13°C and 27°C at 50% relative humidity. Shelf life is 24 months. Do not empty into drains. Dispose of material and containers in a safe manner as per local regulations and SDS.
Proper surface preparation is critical for achieving a reliable structural bond and preventing premature failure in concrete repair applications.
Surface prep: Old concrete must be clean, profiled, or textured. New concrete requires a minimum 28-day cure. All surfaces must be sound and free of dust, dirt, grease, wax, oil, or other contaminants. Smooth concrete should be mechanically roughened with a wire brush or sandpaper.
Primer: Not required. ARDEX RA 142 serves as its own bonding agent.
| Property | Value |
|---|---|
| Colour | Amber tint |
| Mixed Viscosity | 190 cps |
| Gel Time (+24°C) | 20 minutes |
| Compressive Strength (7 days) | 70 MPa |
| Tensile Strength (7 days) | 50 MPa |
| Shear Bond Strength (2 days) | 8 MPa |
| Shear Bond Strength (7 days) | 11 MPa |
| Elongation at break (7 days) | 1.8% |
| Water Absorption (24 hours) | ~0.2% |
| Application Temperature Range | 10°C to 35°C |
| Cure Time (Full) | 24 hours |
| Shelf Life | 24 months |
| Packaging | 470mL dual cartridge |
Here are some common examples on where Ardex RA 142 Structural Crack Injection Epoxy used by our customers.
