Cold Snap Challenging for Concrete Contractors
Sub-freezing temperatures, the likes of which southwest Ohio has seen this past week, create challenges for concrete contractors, especially those working on the new Middletown Regional Hospital.
Workers treat concrete with kid gloves when the weather is so cold that people stay indoors. In favorable weather conditions, it takes 28 days for concrete to cure and reach full strength. Under cold weather conditions, workers use blankets, forced heat and chemical mixtures to insure the concrete sets and cures without damage. During the first two days of the hardening process, concrete generates a certain amount of heat via chemical reaction. This causes steam to rise in the cold air. Additional heating is necessary to ensure water within the concrete mixture does not freeze during the curing process and damage its structural integrity.
Each tier of the five-level hospital requires five to six pours of concrete to complete the floor - in all requiring nearly 31,000 cubic yards of concrete. The hospital is expected to be completed by late 2007, east of I-75 near the Middletown interchange.