About Fosroc Concure PI

Fosroc Concure PI is a single-component, spray-applied liquid membrane curing compound formulated around a high-grade silicate compound. When applied to freshly placed concrete it dries to a thin, clear film that acts as a moisture barrier, holding back the mixing water that cement needs to hydrate. Proper curing is the single most cost-effective way to develop the design strength, abrasion resistance and durability of concrete, yet on Indian sites it is routinely shortcut because traditional methods such as ponding, wet gunny bags and damp sand are water-intensive, labour-heavy and impractical on vertical or large-area pours. Concure PI replaces these methods with a one-pass coating that, once applied, requires no further attention. The product is clear in colour, so it does not stain or discolour the surface and does not interfere with the natural appearance of architectural or fair-faced concrete. It complies with ASTM C 309-97 Type 1, the international standard for liquid membrane-forming compounds for curing concrete. With a coverage of roughly 5 to 6 square metres per litre and a touch-dry time of just 1 to 2 hours, it suits the fast-track schedules typical of commercial floors, infrastructure decks and precast yards. As an authorised Fosroc distributor serving Delhi NCR and Pan-India, Space Arc Engineering supplies Concure PI in standard 20-litre pails with technical guidance on dosage, spray calibration and site sequencing so contractors achieve consistent, code-compliant curing.

The technical insight

The performance of any membrane curing compound is governed by its moisture-retention efficiency, the fraction of mixing water it keeps in the slab during the critical first days. By forming a continuous silicate film as the carrier evaporates, Concure PI restricts evaporation from the exposed surface, which is where plastic shrinkage cracking originates when ambient evaporation rates exceed the rate at which bleed water rises. This matters acutely in Indian conditions: in peak summer across the northern plains, low humidity, high temperature and dry wind can push surface evaporation past the ~1.0 kg/m2/hr threshold at which cracking risk becomes severe, so a film applied at the right moment is decisive. Timing is the key technical control. The compound must go on immediately after the surface bleed water has disappeared following final trowelling, neither so early that it is diluted by surface water nor so late that the surface has already begun to dry and crack. A silicate film is comparatively thin and is not designed to be a permanent sealer or a bond breaker, so where subsequent toppings, screeds, paints, tile adhesives or membranes must bond to the slab, the curing film should be allowed to wear or be mechanically removed, and a small trial patch is advisable before applying bonded finishes.

Where it is used

• Curing of ground-floor and suspended reinforced-concrete slabs in commercial and residential buildings
• Industrial and warehouse floor slabs where uniform strength gain and reduced dusting are required
• Concrete pavements, hardstandings, parking decks and approach roads
• Bridge decks, culverts and other infrastructure elements exposed to drying wind and sun
• Water-retaining and drainage structures such as channels and tanks during the curing window
• Precast and prestressed concrete elements cured in casting yards
• Large-area screeds and toppings where ponding or wet covering is impractical
• Mass-concrete surfaces where minimising moisture loss reduces early thermal and shrinkage cracking

Key advantages

• Forms an effective moisture-retaining film that lets cement hydrate fully for proper strength development
• Reduces plastic shrinkage cracking and surface crazing by limiting early evaporation
• Clear film does not stain or discolour the concrete, suiting fair-faced and architectural finishes
• Single-component and ready to use with no mixing, dilution or batching on site
• Fast touch-dry of 1 to 2 hours keeps follow-on trades moving on fast-track programmes
• Sprayed application covers large areas quickly, cutting curing labour and water consumption
• Eliminates the need for damp hessian, sand or polyethylene sheeting and the water they require
• Complies with the internationally recognised ASTM C 309 Type 1 standard

Limitations & considerations

• A curing membrane, not a waterproofing, protective or decorative coating, and not a sealer-hardener
• The thin silicate film can act as a bond inhibitor; bonded toppings, screeds, tiles, paints or membranes may need the film removed or a trial patch first
• Effectiveness depends on correct timing: applying before bleed water clears, or after the surface has dried, reduces performance
• Single coat at the specified coverage is required for a continuous film; thin or patchy spraying leaves unprotected areas
• Clear film offers no solar reflectance, so it does not reduce surface temperature on slabs exposed to direct sun the way a white-pigmented compound can
• Performance assumes spray equipment is calibrated and the surface is freshly finished concrete, not an old or contaminated substrate
• Shelf life and film integrity depend on correct storage of sealed pails away from heat and direct sunlight

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Concure PI

Concure PI sits in Fosroc’s Concure range as a clear, silicate-based, ASTM C 309 Type 1 curing membrane positioned for general-purpose curing where a transparent, non-staining film is wanted. Within the Fosroc line-up it is commonly compared with wax-emulsion and acrylic resin alternatives such as Concure WB and Concure A/AB, and with white-pigmented grades like Concure LP90 that add solar reflectance for hot, sun-exposed slabs; choose a pigmented grade where surface temperature reduction matters, and Concure PI where a clear finish is preferred. Against competitor products, Concure PI is the direct counterpart to Sika Antisol and Sika curing compounds, MYK (MBCC/Master Builders Solutions) MasterKure curing membranes, Pidilite Dr. Fixit Concure, and STP membrane curing compounds; all serve the same curing function and selection usually turns on standard compliance, film type (clear vs pigmented), coverage economy and local availability. As an authorised Fosroc distributor, Space Arc Engineering recommends Concure PI for clear-film curing and can advise on the right Fosroc grade or a verified alternative for a given exposure, finish requirement and downstream bonding constraint.

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