High fresh concrete and ambient temperatures affect both fresh and hardened concrete properties. They influence workability, strength as well as surface finish and early shrinkage.
Accelerates setting and leads to faster stiffening of the concrete. This shortens the workability of the concrete. To prevent rapid setting, water is often added subsequently to improve the consistency. Disadvantage: The final strength is reduced.
High fresh concrete and ambient temperatures lead to higher early strengths and often lower final strengths in hardened concrete.
Surface finish and early shrinkage
Excessive water evaporation near the surface causes the concrete surface to "die of thirst". This impedes the hydration of the concrete. Negative consequences can be:
- lower strength in the concrete edge zone
- sanding concrete surfaces
- Reduction of durability
- higher water absorption capacity
- Emergence of early shrinkage cracks