For horizontal, vertical, and overhead concrete repairs, ARDEX RA 88 Plus is a non-drip, non-sag epoxy adhesive that fills holes, seals cracks, and sets anchor bolts. It is formulated to bond structurally to major construction substrates—including metal, concrete, brick, wood, stone, and block—and meets AS/NZS 4020 for contact with potable drinking water.
ARDEX RA 88 Plus is a two-component epoxy that cures to a high compressive strength of 87 MPa, making it suitable for structural repairs and spall patching. Its paste consistency allows it to be trowelled flush into overhead or vertical gaps without running or sagging. The adhesive serves as a chemical anchor for bolts, a rigid seal for crack injection ports, and a high-strength termination sealant for selected ARDEX Sheet Applied Waterproofing Membranes inside prepared reglets. In swimming pools, its density allows underwater installation of tiles on side walls or bottom surfaces when applied to a dry tile.
Ensure concrete substrates are a minimum of 28 days old. All concrete surfaces must be clean and mechanically prepared by rough-grinding, scarifying, or bush hammering to achieve a roughened profile. Smooth surfaces like wood or metal must be mechanically roughened with a wire brush or sandpaper. All dust, dirt, oil, and contaminants must be removed by vacuuming prior to application.
To prepare the cartridge, unscrew the plastic cap, remove the plug, and load the cartridge into an ARDEX Heavy Duty Caulking Gun (use the 254ml gun for the 254ml size, or the dual-cartridge gun for the 627ml size). Dispense a small amount of material until both parts flow evenly. Attach the mixing nozzle and purge a small amount of product until the paste has a consistent grey colour with no streaks.
Substrate and ambient air temperatures must be between 5°C and 35°C. If the work site or substrate is below 21°C, condition the cartridges to 21°C–24°C before use to prevent the product from thickening. Clean tools immediately with a mild solvent; cured epoxy can only be removed mechanically. The adhesive must be fully cured before conducting any water flood testing on waterproofing membranes.
Yes, ARDEX RA 88 PLUS is compliant with AS/NZS4020, making it safe for contact with potable drinking water. This allows its use in water tanks, pipe repairs, and other areas requiring drinking water certification.
No, ARDEX RA 88 PLUS is not intended for repairing cracks subject to movement. It is a rigid epoxy designed for static repairs where its high compressive strength is beneficial.
The working time varies with temperature: 90 minutes at 4°C, 45 minutes at 24°C, and 20 minutes at 40°C. Plan your application accordingly, especially in warmer conditions.
No, this product is designed for small patch repairs only. Using it for deeper or larger mass repair areas can generate excessive heat during curing, potentially leading to swelling, smoking, or cracking.
| Application | Key benefit | Primary trades |
|---|---|---|
| Concrete crack and hole repair | Achieves 87 MPa compressive strength at 7 days, providing durable, structural repair for non-moving cracks. | Concreters, general builders |
| Waterproofing membrane terminations | Secures ARDEX sheet membranes and OverFlashing details. Cures in 3 hours at 24°C, allowing faster flood testing. | Waterproofers |
| Overhead and vertical repairs | Excellent non-drip and non-sag performance ensures material stays in place, reducing rework and material waste. | Concreters, repair specialists |
| Anchor bolt installation | Superior bond strength to concrete (20.1 MPa at 14 days) securely fixes anchors without slip. | Plumbers, steel fixers, general builders |
| Underwater pool tile repair | Adheres tiles in wet conditions, allowing targeted repairs without fully draining the pool. | Tilers, pool maintenance |
| Potable drinking water contact | AS/NZS4020 compliance provides assurance for applications in tanks and pipes intended for drinking water. | Plumbers, water infrastructure contractors |
All substrates must be sound, clean, dry, and free of any contaminants. A roughened surface is critical for good adhesion.
Use a grinder to cut the repair area to a minimum depth of 13mm, ensuring clean, square edges. Avoid feather-edging. Roughen the internal surface mechanically.
Mechanically abrade smooth surfaces like metal or stone with a wire brush or sandpaper to create a textured profile for the adhesive to key into.
Correct cartridge setup ensures a perfect 1:1 mix ratio and optimal performance.
Before attaching the nozzle, place the cartridge in the caulking gun and dispense a small amount until both components flow evenly.
Attach the mixing nozzle and dispense material until a consistent, streak-free grey colour is achieved. Discard this initial amount.
Apply the mixed epoxy to the prepared substrate using the appropriate method for the job.
Apply the adhesive to the repair area, slightly overfilling it. Use a trowel to smooth the material flush with the surrounding surface.
Apply a sufficient amount of adhesive to one of the surfaces to ensure complete coverage and fill any gaps when the two parts are brought together.
Allow the material to cure before subjecting it to traffic or mechanical finishing.
Harmful if swallowed. Causes eye and skin irritation and may cause serious eye damage. May cause an allergic skin reaction. May cause respiratory irritation. Suspected of causing cancer. Toxic to aquatic life with long lasting effects. May be corrosive to metals.
Wear protective gloves, clothing, eye protection, and face protection. Ensure adequate ventilation during mixing and application.
Store in original unopened packaging, in a dry place at 23°C and 50% relative humidity for up to 24 months. Check with your local Council regarding the disposal of contents and packaging. Keep out of the reach of children.
Proper surface preparation ensures optimal bond strength and long-term performance. Do not compromise on cleaning or profiling.
Surface prep: New concrete must be at least 28 days old. Mechanically remove all dirt, dust, curing compounds, oils, grease, sealers, and contaminants. Profile the surface by rough-grinding, scarifying, or bush hammering to achieve a roughened texture. Vacuum clean thoroughly.
Primer: Not required, provided the surface is sound, clean, and mechanically profiled.
Surface prep: Ensure surfaces are sound and free from dust, dirt, grease, wax, oil, or any other contaminant. Smooth surfaces must be mechanically roughened with a wire brush or sandpaper to create a profile for adhesion.
Primer: Not required, provided the surface is sound, clean, and mechanically roughened.
| Property | Value |
|---|---|
| Colour Mixed | Grey |
| Working Time | 90 mins @ 4°C, 45 mins @ 24°C, 20 mins @ 40°C |
| Service Temperature After Curing | -7°C up to 50°C |
| Gel Time 60 Gram Mass | 65 mins @ 4°C, 26 mins @ 24°C |
| Tack Free Cure Time | >6 hrs @ 4°C, 3 hrs @ 24°C |
| Compressive Strength | 87 MPa @ 7 days |
| Bond Strength Hardened to Hardened Concrete | 16.9 MPa @ 2 days, 20.1 MPa @ 14 days |
| Bond Strength Plastic to Hardened Concrete | 12.3 MPa @ 2 days |
| Heat Deflection | 51°C |
| Water Absorption | 0.32% |
| Linear Coefficient of Shrinkage | 0.00015% @ 48 hrs |
Here are some common examples on where Ardex RA 88 Plus Multi-Purpose Epoxy Repair Adhesive used by our customers.
