Mass Concrete Adiabatic Temperature Rise Screen (ACI 207)
How hot a thick concrete placement will run, and whether it needs a cooling plan.
Example
You enter
- Total cementitious content (lb/cy) 600
- Adiabatic rise per 100 lb cementitious (degF) 12
- Concrete placing temperature (degF) 70
- Surface-core differential target (degF) 35
You get
- Adiabatic temperature rise 72 degF (over screen - thermal plan)
- Estimated peak temperature 142 degF
Checked against published worked examples from: B. Gajda and M. VanGeem (after PCA Design and Control, 13th ed.).
Details, formula, and sources
ScopeScreens mass-concrete heat: rise = cementitious x coefficient / 100; peak = placing + rise. A rich 600 lb/cy mix at 12 degF/100lb gains 72 degF and, placed at 70 degF, peaks near 142 degF - past the ~35 degF differential that governs cracking, so it needs cooling. A leaner 400 lb/cy slag mix at 8 degF/100lb gains only 32 degF. A screen, not a thermal analysis; the mix data sets the coefficient and the EOR governs.
Formula or tabledelta_t_f = cementitious_lb_per_cy x rise_f_per_100lb / 100; peak_temp_f = placing_temp_f + delta_t_f; exceeds_screen = delta_t_f > diff_limit_f.
Source and editionACI 207 adiabatic temperature-rise identity by name (rise = cementitious x coefficient; peak = placing + rise); a first-order screen.
Free accessThe adiabatic-rise screen is public first-order arithmetic; the rise coefficient and the thermal-control plan come from the mix data and the engineer of record.
What governsEstimate. AHJ and licensed professional govern.
API field namescementitious_lb_per_cy, rise_f_per_100lb, placing_temp_f, diff_limit_f, delta_t_f, peak_temp_f
- Rise coefficient degF per 100 lb cementitious from the mix data; SCMs (slag, fly ash) lower it (~12 default, ~8 with slag). The published portland-cement rule of thumb is 12.8 degF per 100 lb, for 500-1,000 lb/cy and a least dimension over 6 ftmix data / PCA Design and Control (via Gajda and VanGeem, Controlling Temperatures in Mass Concrete)
- Differential target ~35 degF surface-to-core crack-control target the thermal-control plan enforcesACI 207 / engineer of record