Concrete Temperature Calculator

Fresh Concrete Temp is a weighted average of Cement, Water, and Aggregate Temperature, following the fresh-concrete-temperature formula published in ACI PRC-305-20, Guide to Hot Weather Concreting, and mirrored in ACI PRC-306-16, Guide to Cold Weather Concreting -- each ingredient's temperature is weighted by its share of the mix's total heat-carrying mass. Ambient Temperature has no effect on this figure, or on any other output in this calculator: that ACI formula is defined entirely from the temperatures of the ingredients going into the mixer, not the outside air, so entering a hotter or colder job-site temperature leaves Fresh Concrete Temp, the hot/cold risk flags, Ice Needed, and every other output completely unchanged. Aggregate Temperature carries the most weight of the three ingredients in that formula, because a standard mix uses about 3,000 lbs of aggregate against only 564 lbs of cement and 300 lbs of water per cubic yard -- aggregate is genuinely the mix's largest thermal mass, which is why moving it by a given number of degrees shifts Fresh Concrete Temp more than moving Cement or Water Temperature by that same number of degrees.

Hot Weather Risk, Cold Weather Risk, Ice Needed, and Corrected Temp all derive from Fresh Concrete Temp against fixed ACI thresholds (90°F for hot-weather concerns, 40-50°F for cold), so anything that changes Fresh Concrete Temp flows through to those outputs too. This calculator estimates batch temperature only; it does not model heat gain or loss after placement, which ambient conditions do affect in practice.