Concrete Maturity and Equivalent Age (ASTM C1074)
The temperature-honest cure schedule: the Nurse-Saul time-temperature factor (Ta - T0) x hours in deg C-hr, the Arrhenius equivalent age at a 68 F reference, and the hours remaining to the mix's lab-calibrated TTF target. A 50 F week accrues 1,680 C-hr and reads as only 3.8 equivalent days - the cold slab is not '7 days old' - while three days at 90 F carry nearly six days of equivalent age. Datum 0 C and Q = 5000 K for Type I without admixtures, both editable. The strength a TTF represents comes only from the C1074 lab calibration of the actual mix; supplements, not replaces, acceptance cylinders.
Formula and source
M = (Ta - T0) x hours in deg C-hr (Nurse-Saul, one constant-temperature interval); te = exp(-Q x (1/(Ta+273.15) - 1/(Tr+273.15))) x hours (Arrhenius equivalent age, kelvin); target_hours = target_TTF / (Ta - T0) when a calibrated target is given.
ASTM C1074 (Standard Practice for Estimating Concrete Strength by the Maturity Method), by name; both maturity functions with their recommended Type I no-admixture constants.
Audience
This tile is built for trades and the adjacent professions in the Carpentry and Construction group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.