Frequently Asked Questions

When exactly should Concure WB be applied to a freshly placed concrete floor slab and can it be applied too early?

Concure WB must be applied to the concrete surface at the correct stage of concrete finishing — too early and the curing compound is applied to a surface still releasing bleed water, which traps the bleed water under the curing membrane film and prevents proper cement hydration of the surface zone; too late and the concrete surface has already lost significant moisture before the curing protection is in place. The correct application time is immediately after the final finishing operation (after the last pass of the power trowel for a trowelled slab, or after texturing for a broom-finished pavement), when the concrete surface is no longer releasing visible bleed water and the surface sheen of bleed water has disappeared. On a slab being trowelled in sections, the Concure WB should follow the trowelling operation closely — in Indian summer with fast-moving bleed water evaporation, the curing membrane should be applied within 10 to 30 minutes of the final trowelling pass. Application of Concure WB to a smooth concrete surface should be in an even, continuous coat without misses or thin spots — an uneven curing membrane results in uneven curing and differential surface quality. For formed concrete (walls, columns), the curing membrane is sprayed onto the de-shuttered surface immediately after formwork removal, covering all formed faces before the surfaces begin to dry.

Does Concure WB need to be removed before applying a Nitoflor epoxy floor coating or Dekguard anti-carbonation coating?

Yes — Concure WB and other curing compounds form a thin resin film on the concrete surface that acts as a release layer and prevents adhesion of subsequently applied coatings, adhesives, and repair mortars. Before applying any coating (Nitoflor epoxy, Dekguard anti-carbonation, Nitoproof 600 cementitious waterproofing) or any bonded system (tile adhesive, repair mortar with Nitobond, Renderoc BS bonding slurry) to a Concure WB-cured concrete surface, the curing compound film must be completely removed. The standard removal method is light mechanical grinding of the floor surface using a single-disc floor grinder with a medium-grit diamond or metal bond grinding disc, followed by vacuum cleaning to remove all ground residue. Shot blasting is also an effective and faster method for large floor areas. The effectiveness of curing compound removal should be confirmed by a simple water drop test on the prepared surface — if water beads on the surface after preparation, the curing compound is not fully removed and further grinding is needed; if water absorbs uniformly into the surface, the preparation is complete. For formed concrete surfaces (walls, columns) where Concure WB was applied after de-shuttering, the curing compound on vertical surfaces typically degrades more rapidly under UV and rain than on horizontal surfaces, and by the time a wall is to be coated (typically weeks to months after the concrete was cast), the curing compound may have sufficiently degraded that only light preparation (wire brushing or light grinding) is needed before coating.

How does Concure WB compare to wet curing (hessian and polythene) for concrete quality and which method is preferred?

Both Concure WB curing compound and wet curing with hessian and polythene sheeting achieve the same fundamental objective — maintaining adequate moisture in the concrete surface zone during the critical early hydration period — but they work by different mechanisms and have different practical advantages and limitations. Wet hessian and polythene curing is considered the gold standard for curing efficiency: the saturated hessian in direct contact with the concrete surface provides an unlimited moisture supply (supplemented by watering as needed) and maintains the concrete surface at 100 per cent relative humidity throughout the curing period. Studies comparing curing methods consistently show that concrete cured under wet hessian achieves higher 28-day strength (by 5 to 15 per cent) and lower permeability than the same concrete cured with a chemical curing compound — because the curing compound allows some moisture loss (typically 10 to 20 per cent, compared to near-zero with wet hessian), and the concrete surface benefits from the additional hydration enabled by the constant moisture supply. The practical disadvantages of wet hessian curing are significant in Indian construction: it is labour-intensive to lay, keep saturated (requiring watering 3 to 4 times per day in Indian summer heat), and secure to prevent lifting in wind; it is not practical for large floor slabs where laying and removing tonnes of wet hessian is operationally very difficult; and it requires extended site access for the curing period. Concure WB curing compound is preferred for large floor slabs, pavements, and road works where wet hessian is impractical — the compound is applied rapidly by spray and requires no further labour or watering. For bridges, precast elements, and critical structural elements where maximum strength and minimum permeability are required, wet hessian or wet cotton mats under polythene is still the preferred curing method supplemented by Concure WB on inaccessible surfaces.