From the moment it reaches the site until it is placed and hardens, concrete is highly sensitive to weather conditions. Rapid setting and slump loss in summer and slower strength development in winter directly affect both quality and the construction schedule. The good news is that most of these problems can be controlled by using the right admixture at the right dosage.
1. Maintain workability in hot weather
High temperatures accelerate cement hydration. Concrete leaving the batching plant may have lost much of its workability by the time it arrives on site. Trying to restore slump by adding water on site raises the water/cement ratio and lowers strength and durability. Instead, polycarboxylate-based superplasticizers that maintain workability during transport and set retarders should be used. BiyoFlow PCE and BiyoRetard are among our products developed for this need.
2. Accelerate early strength in cold weather
At low temperatures concrete hardens slowly, formwork stripping times increase and fresh concrete is at risk of freezing. Set and early-strength accelerators bring strength development forward and reduce this risk. In reinforced concrete, chloride-free accelerators should be chosen so as not to trigger reinforcement corrosion. BiyoAccel is designed for cold-weather concreting and precast production.
3. Entrain air against freeze–thaw
For bridges, roads and outdoor concrete exposed to winter conditions, the real danger is the repeated freezing and thawing of water inside the concrete. Air-entraining admixtures create microscopic, evenly distributed air bubbles that give freezing water room to expand. BiyoAir is used for this purpose; the target air content should always be verified by laboratory and site measurements.
4. Plan waterproofing at the design stage
In foundations, retaining walls and water structures, insulation applied afterwards is both costly and vulnerable to damage. Crystalline waterproofing admixtures work within the concrete’s own capillary pore structure to reduce water ingress. BiyoProof is a powder admixture designed for this need.
5. Don’t decide without trial mixes
Every combination of cement, aggregate and admixture behaves differently. When selecting an admixture:
- Prepare laboratory mixes with the cement and aggregates to be used,
- Measure slump and slump loss over time,
- Compare early and 28-day compressive strengths,
- Check the compatibility of admixtures with each other.
Performance requirements for concrete admixtures are defined in EN 934-2; we recommend requesting certificates of conformity to this standard when selecting products.
Frequently asked questions
Why is adding water to concrete on site a problem?
Every litre of added water raises the water/cement ratio. This lowers compressive strength, increases permeability and raises the risk of shrinkage cracking. If workability is being lost, the solution is to use the right combination of plasticizer and retarder at the plant or, where necessary, to add plasticizer on site as recommended by the manufacturer.
Can I use more than one admixture in the same concrete?
Yes, a plasticizer is often used together with a retarder or an air-entraining agent. However, admixtures should not be added at the same time and at the same point, and their compatibility should be verified in advance with laboratory trials. Incompatible combinations can cause unexpected slump loss or changes in air content.
How do I determine the right dosage?
The range in the manufacturer’s technical data sheet is a starting point. The exact dosage should be determined through trial mixes based on cement type, fines content, aggregate properties and target workability. Reviewing the dosage when the season changes is also good practice.
Conclusion
Weather conditions cannot be changed, but how concrete responds to them can be managed. The right admixture choice means fewer site problems, a more predictable schedule and longer-lasting structures.
Related products: Concrete Admixtures
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