Retarder for exposed aggregates

Construction chemical company Mapei has established itself in the local market as a supplier of innovative system solutions and technical services to assist the market.

Mapei’s local technical expertise is backed up by the latest international research, development and production methods, resulting in international standard products ideally catered for the local market.

Mapei SA is known for its impressive range of concrete admixture products and solutions, one of which is Mapetard SS, a water-based retarder used to expose aggregates in horizontal surfaces for aesthetic purposes or construction joints. From an environmental point of view, Mapetard SS is a suitable alternative for exposed aggregates, as water is the only solvent present.

Application of Mapetard SS during placement or onto freshly placed concrete is an eff ective and time-saving method of preparing exposed aggregates, finishes or construction joints. The water-based retarder will penetrate the fresh concrete to a depth of 5-15mm, depending on the amount applied. This layer will not be set when the rest of the concrete has hardened, thus allowing the surface mortar to be washed away around the uppermost aggregates.

When treating exposed horizontal surfaces, a brush or spray may be used to apply Mapetard SS onto the fresh concrete surface immediately after fi nishing. A form oil sprayer may be used for application. The thickness of the coating should be similar to that of a lacquer. Mapetard SS contains a white pigment which makes it easy to see the

thickness and uniformity of the coating over the entire surface. Hosing off the retarded surface mortar with water reveals a clean, rough surface. The aggregates are partially exposed and, in the case of construction joints, will enhance bonding to subsequent layers. Normal consumption is 0,1kg/m².

(Above): Mapetard SS was recently applied at an entrance at Waterfall Equestrian Estate to give the concrete an exposed fi nish.

(Above): Mapetard SS was recently applied at an entrance to the Waterfall Equestrian Estate to give the concrete an exposed fi nish.