Fresh Concrete Temperature (ACI 305.1)
The temperature of fresh concrete as batched, from the ACI 305.1 ingredient heat balance.
Example
You enter
- Aggregate weight (lb) 3000
- Aggregate temperature (°F) 80
- Cement weight (lb) 564
- Cement temperature (°F) 150
- Added (mix) water weight (lb) 240
- Mix water temperature (°F) 70
- Free moisture on aggregate (lb) 60
You get
- Fresh concrete temperature 85.8 F
Checked against published worked examples from: Portland Cement Association.
Details, formula, and sources
ScopeT = [0.22(Ta Wa + Tc Wc) + Tw Ww + Twa Wwa] / [0.22(Wa + Wc) + Ww + Wwa], solids weighted by their ~0.22 specific heat and water by 1.0. Aggregate 3000 lb at 80 F, cement 564 lb at 150 F, 240 lb of 70 F water, and 60 lb of aggregate moisture batch to 85.8 F. Water's heat capacity is four times the solids', so chilling the mix water or adding ice is the cheapest way to beat the ~90 F hot-weather ceiling. A batching aid; the mix design governs.
Formula or tableT = [0.22(Ta x Wa + Tc x Wc) + Tw x Ww + Ta x Wwa] / [0.22(Wa + Wc) + Ww + Wwa]; solids specific heat 0.22 Btu/lb-F, water 1.0, aggregate free moisture at the aggregate temperature.
Source and editionACI 305.1 Specification for Hot Weather Concreting (the batch heat-balance for fresh concrete temperature); PCA Design and Control of Concrete Mixtures, by name; the mix design and project specification govern.
Free accessThe mass-weighted heat balance is first-principles; the 0.22 solids specific heat is the standard ACI value. Ingredient weights and temperatures come from the batch ticket.
What governsEstimate. AHJ and licensed professional govern.
API field namesagg_weight_lb, agg_temp_f, cement_weight_lb, cement_temp_f, water_weight_lb, water_temp_f, agg_moisture_weight_lb, concrete_temp_f
- Specific heats solids (cement + aggregate) ~0.22 Btu/lb-F, water 1.0; aggregate free moisture at the aggregate temperatureACI 305.1
- Omits cement heat of hydration and mixer friction, which add a few degreesscope of this tile