Vetotard XT428 is a single component concrete surface retarder. Vetotard XT428 is a chemical retarder directly applied to the form-work. It is designed to provide a simple, economical method of exposing aggregates in freshly poured facedown pre-cast concrete or face-up panels or slabs. Vetotard XT428’s function is to retard the hydration of cement at the surface matrix of the concrete.
Seal timber form-work with a suitable polyurethane sealer. Clean form-work and molds and dry before application.
Vetotard XT428 should be applied in one even coat using a brush or roller. The coverage rate is 5 - 8 m2 per liter.
It is possible to spray Vetotard XT428 but would need to dilute with 5 - 10% water to achieve sprayable consistency. Stir well before use.
Before concrete is placed, the surface retarder should be dry for face-down application. This typically takes 15 to 60 minutes depending on ambient conditions, whereas, in the case of face-up, Vetotard XT428 should be applied immediately after concrete placement is complete in wet conditions.
Immediately after the concrete molds are stripped, the retarded surface of the concrete can be exposed either by brushing and/or water washing. Water washing should be carried out using a high-pressure water jet between 1000 and 2000 psi (5 to 10 N/mm2). Dry brushing requires the use of a wire brush.
To bring out the full color of the aggregate for decorative finishes, wash the concrete face with a dilute hydrochloric acid solution (5% concentration).
Clean all tools and equipment with water immediately after use.