A water-based concrete treatment that delays the surface setting of fresh concrete, enabling easy exposed aggregate finishes and superior bonding surfaces.
Water-Based & Eco-Friendly: Safe, non-toxic formula with zero VOCs.
Consistent Exposed Finish: Uniform aggregate exposure without acid washing or heavy chipping, saving labor.
Controlled Depth Etch: Adjustable etch depth up to 10 mm by varying application thickness.
No Strength Impact: Does not weaken concrete or steel bond, preserving full structural strength.
Product Introduction
Unlike concrete retarder admixtures mixed into the batch, this surface-applied treatment targets only the top layer (approximately 1–10 mm). It chemically delays cement hydration at the surface, so that thin mortar layer can be washed off after curing to expose the solid aggregate beneath. Meanwhile, the underlying concrete cures normally, meaning overall strength and set time are unaffected.
It’s ideal for projects requiring an exposed aggregate look or a rough bonding surface. Common applications include decorative, slip-resistant finishes on pavements, walkways, and facades, as well as preparation of construction joints on precast panels, bridge decks, and other structural elements. The paste can be applied to various formwork materials (steel, wood, bamboo) or directly onto fresh concrete, and remains effective even in hot weather or under steam curing conditions. It also provides a generous removal window (up to 72 hours under standard conditions), giving contractors flexibility in when they expose the aggregate. By replacing labor-intensive acid etching or surface chipping, it saves time and ensures a more uniform result
Product Parameters
| Property | Value |
| Appearance | Milky white, homogeneous paste |
| pH | 6–8 |
| Open Time | ≥10 hours |
| Retardation Time | ≥72 hours (room temperature); ≥12 hours (at 60°C) |
| Etching Depth | 1–10 mm (adjustable based on application thickness) |
| Impact on Final Concrete Strength | None |
| Storage Stability | No separation or precipitation |
Product Usage
Application Steps:
Surface Preparation: Ensure the formwork or concrete surface is clean and free of debris or sealants. (For fresh pours, apply after any bleed water has evaporated; for formwork, the forms should be dry and uncoated by release agents in areas to be treated.)
Even Application: Stir the retarder if needed and apply a uniform, even coat at the desired thickness using a brush, roller, or sprayer. Full, consistent coverage is critical to achieve uniform exposure depth.
Standard Curing: Allow the concrete to cure as normal. The retarder will prevent the top surface mortar from hardening during this period while the underlying concrete gains strength. (If applied to formwork, pour the concrete once the retarder film is ready and proceed with curing.)
Exposure: After the appropriate delay, remove the formwork (if used) and rinse off the softened surface mortar using a hose and stiff brush or low-pressure washer. The aggregate will be revealed, leaving an exposed finish or rough bonding texture. Any retarder residue should be thoroughly washed away.
Precautions & Tips:
Apply the retarder evenly at the recommended coverage rate to avoid patchy results. Consider using a pigmented formulation or tracer to help monitor coverage if available.
Do not apply to overly wet or sealed surfaces. For horizontal concrete, wait until bleed water disappears and avoid using curing compounds before applying the retarder. For formwork applications, ensure no form-release oil is present on the areas where retarder is applied, as it may hinder penetration.
If high winds, excessive heat, or heavy rain are anticipated during the curing period, protect the treated surface with plastic sheeting to prevent premature drying or wash-off of the retarder.
Plan the removal and washing at the proper time. Under normal conditions, the retarder can keep the surface paste workable for up to about 72 hours; under accelerated curing (e.g. ~60°C steam curing), expose the aggregate within roughly 12 hours for best results. Always test a small section if unsure – the surface paste should come off easily without dislodging aggregate.
Using a surface retarder eliminates the need for harsh acids or intensive mechanical scabbling to expose aggregate. This makes the process safer, faster, and more consistent compared to traditional methods, while maintaining the concrete’s quality and appearance.
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Our products have undergone rigorous testing at our national testing laboratory (CABR testing center co., ltd). Renowned Fortune Global 500 firms such as China Railway Group Limited, China Communications Construction Company Limited, and Sinohydro are among our esteemed clients.
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