The problem on site
On construction sites across India, one of the most frustrating challenges faced by contractors, project managers, and site engineers is the appearance of cracks across freshly cast concrete slabs within the first 24 hours. These cracks often emerge before the concrete has even achieved its initial set, long before structural loading takes place.
Plastic shrinkage cracks typically appear as parallel or diagonal fissures across the surface of large horizontal pours, such as industrial flooring, bridge decks, concrete pavements, and building floor slabs. They range from shallow hairline crazing to deeper, wider fractures that extend several centimeters into the matrix. While structural engineers evaluate them to ensure they do not immediately compromise the load-bearing capacity of the element, early-age cracks present serious long-term risks. They allow premature penetration of moisture, salts, and atmospheric contaminants, accelerating reinforcement corrosion and surface degradation over time.
Remediating early cracks once they have developed causes project delays, unexpected repair costs, disputes with clients, and unsightly blemishes on architectural and industrial surfaces. Preventing them during the pour and initial setting stage is far more practical than attempting to repair them after hardening.
Why it happens
Freshly placed concrete contains water necessary for both cement hydration and placing workability. Once the concrete is poured, compacted, and leveled, the heavier aggregate and cement particles settle downward due to gravity, displacing free water toward the upper face. This upward movement is known as bleeding, and the water that reaches the top is bleed water.
At the same time, the surrounding environment begins pulling moisture from the exposed slab surface through evaporation. In warm climates, or on open sites exposed to direct sun and continuous wind, the rate of surface moisture evaporation frequently exceeds the rate at which bleed water can naturally rise to replace it.
When evaporation outpaces bleeding, the immediate surface skin begins to dry out rapidly while the concrete beneath remains soft, plastic, and low in tensile strength. As the top layer loses moisture, it attempts to contract. Because the underlying bulk concrete has not yet developed enough cohesion or tensile capacity to resist this differential shrinkage, the upper layer tears apart, resulting in plastic shrinkage cracks.
Traditional mitigation techniques often fail to keep pace with rapid placement schedules:
- Ponding: Creating bunds and keeping water standing on horizontal surfaces is effective, but it is slow to set up, requires massive volumes of water, and is completely impractical on sloped, inclined, or elevated slabs.
- Wet hessian or burlap: Covering the slab with wet cloth requires continuous re-wetting. If the fabric dries out in the wind, it acts as a wick, accelerating moisture loss rather than preventing it. Additionally, placing heavy hessian too early can mark or damage the fresh finish.
- Misting or fogging: Spraying water into the air above the pour helps, but on windy sites, keeping fine droplets positioned directly over the slab without washing out the cement paste is difficult to manage.
How Space Arc Engineering approaches it
Space Arc Engineering acts as an authorized project distributor and technical solution provider, bridging the gap between material science and field execution. Rather than simply supplying materials, Space Arc Engineering assesses site conditions, ambient weather forecasts, and pour geometry to establish a dependable curing strategy.
The technical team at Space Arc Engineering understands that preventing early drying shrinkage is fundamentally about timing. Applying a curing barrier too early, while surface bleed water is still pooling, can dilute the material or disrupt the cementitious finish. Applying it too late, after the surface has already dried and micro-cracks have started to form, renders the barrier ineffective. Space Arc Engineering works alongside site engineers to ensure the material is staged, mixed, and applied at the precise window when the surface water sheen has evaporated, keeping the critical moisture locked inside the fresh matrix.
The system we supply
To eliminate early moisture loss on large flatwork, Space Arc Engineering supplies Fosroc Concure WB, manufactured by Fosroc. Space Arc Engineering is an authorized distributor for Fosroc construction chemicals, delivering factory-fresh materials directly to infrastructure and commercial job sites.
Fosroc Concure WB is a water-based, membrane-forming concrete curing compound. When applied onto newly placed concrete, it forms a continuous, imperious protective skin over the surface. This membrane acts as a physical barrier that dramatically reduces moisture evaporation from the plastic concrete, allowing complete cement hydration and preventing rapid differential shrinkage.
Fosroc Concure WB offers several distinct operational benefits on site:
- Holds moisture in the fresh surface: By sealing the top face immediately after finishing, the compound retains the internal water needed for early hydration, helping the surface develop uniform tensile strength before internal stresses cause cracking.
- Practical where ponding is not possible: Because it is a surface-applied chemical membrane, it eliminates the need for water retaining bunds, continuous water supplies, and constant wetting schedules. It works seamlessly on sloped surfaces, vertical face edges, and areas with limited site water access.
- Fast to apply over large pours: The liquid compound is designed for quick application using mechanical or manual spray equipment, enabling site teams to protect hundreds of square meters of slab in a fraction of the time required by traditional curing methods.
What to check before you order
Before purchasing and applying a concrete curing compound, site engineers and procurement teams should verify specific project criteria to ensure seamless integration with subsequent work:
- Subsequent finishes: Confirm whether the concrete will later receive coatings, epoxies, screeds, ceramic tiles, or waterproofing membranes. While water-based curing compounds naturally degrade over time through weathering and UV exposure, any residual membrane may need mechanical removal (such as light grinding or scarifying) before applying adhesive toppings.
- Application equipment: Ensure that clean, low-pressure compression sprayers or automated spraying rigs are available on site with appropriate nozzles to achieve a consistent, uniform spray fan across the entire slab.
- Pour schedule and surface monitoring: Establish a clear protocol for observing the slab after screeding and floating. The product must be applied as soon as the initial bleed water sheen has disappeared, but before the surface has turned dry and pale.
- Storage and mixing: Store the containers away from direct sunlight and extreme temperatures, and ensure the product is agitated thoroughly before use in accordance with the manufacturer instructions.
Talk to our technical team
Do not let plastic shrinkage cracks compromise the appearance, schedule, and durability of your concrete pours. Space Arc Engineering provides technical guidance, logistics coordination, and reliable material distribution to help your project maintain quality standards from day one.
Explore our solutions to view our full portfolio of concrete chemicals, grouts, and repair systems. Contact our engineering desk directly to discuss your project pour schedule and curing compound requirements:
- Phone: +91 99991 55255
- Phone: +91 72900 89007
- Website: www.space-arc.in