Permacolour Surface Retarders are solutions of chemicals which react with cement in the concrete surface and retards the set of the surface layer to a depth of between 3mm and 12mm while the underlying concrete sets. This enables the concrete surface to be removed easily, often by brushing or water blasting and exposes the aggregate to give the depth of the etch to the concrete.
These retarders come in two forms:
- SR20 - Maximum strength of concrete - 20MPA
- SR25 - For concrete strengths over 20MPA
Permacolour Surface Retarders are used only on horizontal concrete surfaces to expose the aggregate, it can also be used to form a mechanical key to improve the key of new concrete to old concrete
**As a general rule, the depth of etching should not be greater than one-third of the mean diameter of the aggregate.
- Permacolour Surface Retarders are supplied ready-to-use
- No need for any mixing and MUST NOT BE DILUTED.
- If a high powered water blaster is being used, take particular care as not to leave the nozzle aimed in one particular spot for a long time.
- Do not leave the treated surface longer than the specified time because a concrete surface will harden and render the retarder useless.
- Always wash out spraying equipment with warm water.