Concrete Evaporation Calculator
This concrete evaporation calculator implements the ACI 305R hot-weather formula (Uno's equation): from concrete temperature, air temperature, relative humidity and wind speed it computes the surface evaporation rate and flags plastic-shrinkage cracking risk.
Como usar esta calculadora
- Insira suas dimensões — pés para comprimentos, polegadas para a espessura.
- Ajuste as opções — porcentagem de desperdício, tamanho do saco e o preço local do concreto.
- Leia seus resultados — volume, sacos, peso e custo são atualizados ao vivo enquanto você digita.
A fórmula
E = 5([Tc+18]²·⁵ − rh[Ta+18]²·⁵)(V+4)×10⁻⁶ kg/m²/h — risk threshold 1.0 kg/m²/h (0.2 lb/ft²/h) Exemplo resolvido: Concrete 25 °C, air 28 °C, 50% RH, 15 km/h wind → ≈ 0.7 kg/m²/h: moderate risk — fog spray or evaporation retarder advised.
Plastic-shrinkage cracks form when the surface dries faster than bleed water rises — a race measured by this evaporation rate. Above 1.0 kg/m²/h (0.2 lb/ft²/h), cracking is likely on unprotected flatwork; between 0.5 and 1.0, be ready to act.
Wind is the silent multiplier: at the same temperatures and humidity, going from calm to a 20 km/h breeze can triple the rate. Windbreaks are as effective as timing.
Countermeasures in order of effort: schedule the pour for morning/evening, fog-spray above the surface, apply evaporation retarder after screeding, windbreaks and sunshades, and cure immediately after finishing.
Perguntas frequentes
Perguntas comuns sobre a concrete evaporation calculator.
What evaporation rate cracks concrete?
Above 1.0 kg/m²/h (0.2 lb/ft²/h), plastic-shrinkage cracking is likely per ACI 305R. Some spec limits are stricter (0.5) for silica-fume mixes with little bleed water.
What conditions are worst?
Warm concrete, dry air and wind — a hot mix on a breezy low-humidity afternoon. Cold-weather pours can also crack when warm concrete meets dry winter air.
How do I lower the rate?
Pour early or late, cool the mix, fog spray, use evaporation retarders, erect windbreaks, and start curing (wet cover or compound) immediately after finishing.
Does this affect strength?
The cracks are shallow but let in water and chlorides, hurting durability. Severe surface drying also weakens the wear surface itself.
Calculadoras relacionadas
Mais ferramentas da família de calculadoras de concreto.