Placing Antifreeze Concrete at Grand Forks Air Force Base

摘要

The first airfield pavement application of a recently developed antifreeze technology for cold weather concreting was demonstrated in February 2004 on an unreinforced section of a parking apron at the Grand Forks Air Force Base (GFAFB) in North Dakota. The technology, which combines ordinary concrete admixtures into a formulation that depresses the freezing point of water and accelerates the hydration rate of portland cement, was the product of a three- year study conducted for the Federal Highway Administration and completed in February 2004. One of the eight admixture combinations developed in that study was used to convert a standard concrete mixture into antifreeze concrete at GFAFB. Two trial batches of concrete made on the day prior to working on the apron afforded the ready-mix producer ample time to adjust admixture dosages to produce a workable concrete. Four truckloads of concrete were sequentially batched at the ready-mix plant and dosed with the antifreeze formulation at the jobsite. Except for the second truckload, which was later discovered to have damaged mixing fins inside its drum, the antifreeze concrete batched in this study behaved like normal fast-setting concrete during mixing, at the time of placement, and throughout finishing. The apron section was ready for traffic two days after placement in subfreezing weather.