What are the rules for placing concrete in cold weather on Michigan DOT projects?

"T. Weather and Temperature Limitations 1. Protection Against Rain . Protect the concrete pavement from damage by rain. 2. Protection from Cold Weather . Protect the concrete pavement from freezing until it attains a compressive strength of at least 1, 000 psi . Remove and replace concrete slabs damaged by cold weat her, as directed by the Engineer, and at no additional cost to the Department. 3. Cold Weather Limitations . Do not place concrete pavement until the ambient air temperature away from artificial heat is at least 25°F and rising, unless otherwise approved by the Engineer . Do not place concrete pavement if portions of the base, subbase, or subgrade layer are frozen, or if the grade exhibits poor stability from excessive moisture . Protect the concrete surfaces using insulating blankets or polystyrene insulation wi th a minimum R -v alue of 7.0 if the National Weather Service forecasts air temperatures below 40°F for more than 8 consecutive hours during the curing period . Plastic sheeting may be used instead of insulating blankets or polystyrene insulation if the Natio nal Weather Service forecasts air temperatures above 32°F during the curing period." [3] "5. Concrete Temperature Limitations. At the time of concret e placement, ensure a concrete temperature from 45°F to 90°F." [3]

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