Concrete Temperature Rise Calculator

Enter project and mix inputs

Cement content (kg/m3)

Typical: 250–450 kg/m3.

Heat of hydration (kJ/kg cement)

Depends on cement type and age of heat.

Concrete density (kg/m3)

Normal-weight often ~2400 kg/m3.

Specific heat (kJ/kg*C)

Common estimate: 0.84–0.92 kJ/kg*C.

Efficiency factor (0–1)

Accounts for heat losses to forms and environment.

Initial concrete temperature (C)

Place temperature before significant hydration heating.

Calculate Reset

Example data table

Examples assume density 2400 kg/m3 and specific heat 0.88 kJ/kg*C.

Formula used

The model treats hydration as a heat source and estimates the adiabatic rise, reduced by an efficiency factor for heat losses.

• Total heat per cubic meter: Q = H x C x eta
• Temperature rise: dT = Q / (rho x cp)
• Estimated peak temperature: Tpeak = Tinitial + dT

Where H is heat of hydration (kJ/kg cement), C is cement content (kg/m3), eta is efficiency (0-1), rho is density (kg/m3), and cp is specific heat (kJ/kg*C).

How to use this calculator

1. Enter cement content from your mix design or batch ticket.
2. Use a representative hydration heat value for your binder system.
3. Keep density and specific heat at defaults unless you have better data.
4. Set the efficiency factor lower for thin members and cold forms.
5. Click Calculate to view rise, peak temperature, and export options.

1) Why temperature rise matters

Concrete heats up as cement hydrates, and that temperature rise can create tensile stress when surfaces cool faster than the core. In restrained members, cracking may appear within the first days. Estimating rise early supports pour sequencing, insulation planning, curing decisions, and realistic expectations for strength gain and durability overall.

2) What drives hydration heat

Hydration heat depends on cement chemistry, fineness, supplementary materials, and the maturity period considered. High early‑strength binders can release more heat quickly. Slag and fly ash often reduce and delay heat. This calculator treats heat as energy per cubic meter, then converts it to adiabatic rise adjusted for losses.

3) Reading the key inputs

Enter cement content from the fresh mix, then select a heat of hydration value from supplier data or testing. Density and specific heat describe the concrete’s thermal mass; heavier mixes and higher heat capacity reduce rise. The efficiency factor represents heat escaping through forms, soil, wind, and placement duration.

4) Typical ranges you can benchmark

For normal‑weight concrete, density is about 2400 kg/m3 and specific heat about 0.88 kJ/kg*C. Cement content ranges 250–450 kg/m3. Heat of hydration may range 240–320 kJ/kg for cements, yet can be higher. Efficiency frequently falls between 0.60 and 0.90.

5) Interpreting dT and peak temperature

The calculator reports dT and an estimated peak temperature by adding dT to the placement temperature. Treat the peak as a planning indicator, not a guarantee, because geometry and boundary conditions matter. Peaks above roughly 70C may increase delayed ettringite risk. Large rises can also magnify core‑to‑surface gradients.

6) Managing risk on site

Reduce peak temperature by lowering cement content, using low‑heat cement, adding slag, or chilling water and aggregates. Increase heat loss with thinner lifts, longer intervals, or cooled forms, but watch for rapid surface cooling. Insulation blankets can reduce gradients. Consider limit values such as 20C differential in critical pours.

7) Monitoring and documentation

Field monitoring improves confidence. Embed thermocouples at the core and near surfaces, record temperatures at regular intervals, and correlate with curing actions. Compare measured peaks against the estimate to refine your efficiency factor for future pours. Document ambient conditions, mix tickets, and insulation details so data remains usable long‑term.

8) Using results with engineering judgment

Use the results alongside structural restraint, member thickness, and specification requirements. If the estimate suggests high peaks or large gradients, coordinate with the engineer for a mass concrete plan, including pre‑pour trials, placement temperature targets, and contingency measures. Export the CSV or PDF to share assumptions and calculations traceable.

1. What does the efficiency factor represent?

It approximates the fraction of hydration heat that stays in the concrete. Lower values reflect greater losses to forms, soil, air, wind, and long placement times. Calibrate it using thermocouple data from similar pours.

2. Is this calculator valid for all member sizes?

It is a planning estimate. Thick, insulated, or buried elements behave closer to adiabatic conditions, while thin walls lose heat quickly. Use geometry‑specific monitoring or a detailed thermal model for critical mass concrete.

3. Where can I get heat of hydration values?

Use cement or binder supplier data, adiabatic calorimetry results, or historical project records. If you only have 7‑day heat, treat it as an upper bound for early peaks and adjust with experience.

4. What placement temperature should I use?

Use the measured discharge or in‑place temperature at placement, after considering haul time and weather. For hot conditions, also check aggregate and water temperatures because they strongly influence the starting value.

5. How do I reduce peak temperature effectively?

Lower cement content, use low‑heat cement, replace cement with slag, or cool materials with chilled water or ice. In extreme cases, staged placements, cooling pipes, or insulated forms can control both peak and gradients.

6. What results suggest cracking risk?

Large dT and steep core‑to‑surface differentials increase risk in restrained members. Watch for rapid cooling at exposed surfaces, especially in cold or windy weather. Compare your project limits, often around 20C differential, and act early.

7. Can I use the exported report for documentation?

Yes. The CSV is useful for logs and spreadsheets, while the PDF supports submittals and daily reports. Include your input sources and assumptions so reviewers understand the basis of the estimate.

Answers are kept concise for quick jobsite reference.