Weather is one of the most unpredictable—and impactful—variables in concrete performance. Even a well-designed mix can struggle when exposed to extreme heat, wind, low humidity, or cold temperatures during early-age curing.
Rapid evaporation
Plastic shrinkage cracking
Crusting (surface sets faster than interior)
Early moisture loss before hydration stabilizes
Slow hydration and low early strength
Extended bleed times
Freezing of near-surface water
Damage to the pore structure from ice expansion
Traditional wet curing methods—spraying, ponding, blankets, curing compounds—try to compensate. But they are highly sensitive to field conditions and human execution. If a crew misses a re-wetting cycle, applies membrane inconsistently, or encounters a surprise temperature swing, the curing process can be compromised.
To build more weather-resilient slabs, many teams are now relying on internal curing admixtures—such as the nano-silica technology in E5® Internal Cure—which help the concrete retain moisture from within, making curing less dependent on ideal jobsite conditions and perfect timing.
In hot or windy environments, evaporation can exceed the rate at which bleed water reaches the surface. When this happens, the slab can lose curing water before the cement has hydrated sufficiently.
Common outcomes include:
When surface moisture disappears too quickly, the concrete contracts early, creating shallow cracks within hours of placement.
The surface sets faster than the interior, making finishing difficult and potentially causing tearing or blistering.
Even if blankets or water are applied later, moisture that leaves during the first few hours cannot be replaced. Hydration slows, and long-term shrinkage increases.
When early hydration is incomplete, the paste develops more capillaries and voids.
Surface curing methods—misting, fogging, wet burlap—are all designed to slow evaporation, but they do not address the internal water demand of modern low w/c ratio mixes. Internal moisture loss cannot be reversed once it happens.
Internal curing admixtures offer a fundamentally different approach: instead of fighting evaporation at the surface, they help retain moisture inside the matrix.
Nano-silica systems like E5® Internal Cure:
Attract and hold water molecules within the concrete
Control the water of transport and water of convenience
Reduce evaporation even under low humidity, high wind, and direct sunlight
Eliminate the need for wet curing and topical curing compounds
For contractors working in extreme weather, this means:
The concrete stays workable and hydrated longer—even when conditions would normally accelerate surface drying.
Internal curing reduces the moisture gradient between the surface and the interior.
Because curing water is stored inside the slab, the system becomes far less sensitive to environmental swings.
Hydration continues uniformly, reducing permeability, cracking, and curling later in the slab’s life.
Internal curing doesn’t replace good concreting practices—but it makes them far more forgiving.
Cold weather creates the opposite challenge: hydration slows dramatically, and bleed water may remain at or near the surface far longer than expected. If temperatures drop below freezing and that water expands, it can damage the pore system before the concrete reaches adequate strength.
Key risks include:
Delayed setting
Soft or weak surface zones
Freeze–thaw damage
Micro-cracking from ice expansion
Reduced long-term durability
Testing on concrete containing internal curing admixtures (including E5® Internal Cure) demonstrates:
A freeze–thaw durability factor of 89, exceeding the ASTM C494 requirement of 80—even with lower air content than typically recommended for freeze–thaw exposure.
Why this matters:
With fewer bleed channels and a denser internal matrix, there is less water available to freeze—reducing internal damage potential.
This lowers the risk of early-age frost damage.
A denser, less porous matrix is more resilient to cycles of freezing and thawing across the service life.
You still need to follow ACI cold-weather guidelines—heating, insulation, windbreaks, and protection—but internal curing gives the slab an inherent durability advantage under freeze–thaw stress.
Traditional wet curing places enormous pressure on crews to execute perfectly:
Keeping blankets wet
Ensuring curing compounds are uniform and unbroken
Adjusting to surprise weather shifts
Coordinating curing around finishing and saw-cutting
Managing multiple re-wetting cycles across a 24/7 schedule
Field conditions rarely allow perfection.
The E5® Analysis Guide highlights how difficult it has become to consistently perform surface-only curing correctly as timelines compress and field labor varies.
Internal curing reduces this dependency:
Moisture is already inside the concrete.
Internal moisture management replaces membrane-forming products.
The slab has a built-in buffer against rapid changes.
Curing quality is embedded in the mix design instead of being dependent on jobsite conditions.
In extreme weather, consistency matters more than anything—and internal curing is one of the most reliable tools for achieving it.
Yes. Internal curing supports hydration, but you still need proper mix temperatures, insulation in cold weather, and basic environmental control. The difference is that the slab becomes much less vulnerable to rapid moisture loss or late-age freezing.
Third-party testing shows that concrete with internal curing typically exhibits increased slump with no change in air content and only minor changes in final set time—well within ASTM C494 limits.
In the field, contractors often report that concrete remains finishable longer in hot, windy weather.
Exterior pavements and parking lots
Slabs exposed to wind or direct sun
Freeze–thaw environments
Fast-track schedules where wet curing is difficult
Parking decks, sidewalks, and civil infrastructure
Any low w/c slab where moisture loss is a risk
Internal curing can be used in virtually all types of concrete, including structural, slab-on-grade, and slab-on-metal deck placements.
Extreme temperatures—hot or cold—attack the same weak point:
the concrete’s ability to maintain internal moisture long enough for proper hydration.
Traditional wet curing tries to defend this from the surface.
Internal curing protects it from within.
By reducing evaporation in hot and windy conditions, improving early hydration in cold conditions, and eliminating the need for wet curing and curing compounds, internal curing technologies help produce more durable, crack-resistant slabs with far less sensitivity to weather and human error.
Weather may be unpredictable, but concrete performance doesn’t have to be.
Use the TDS to:
Review dosage rates and mixing instructions
Understand evaporation control in hot/windy climates
See freeze–thaw durability results
Compare internal curing vs. traditional wet curing
Build a more robust curing plan for extreme-weather placements
A stronger curing plan starts with the right information—especially when the weather won’t cooperate.