Insight from the DOT

  At night, they use modified concrete... (night pours)    In this instance they're doing (1" to 2" thick... an overlay) a walkway on    bridge.  The acceptable evaporation for this pour is .1 pounds per foot per hour.    If this rate increases due to wind change, relative humidty or temperature, and they are out of  spec., the job won't start or they'll halt it.... In a day pour, it can change to .2 pounds per foot per hour, it must be below that to pour. While the Kestrel 4000 will give you all you need to calculate the evaporation rate,...

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Kestrel & Laying Concrete

 Plastic Shrinkage Cracks are a costly problem for concrete professionals- they occur when the surface of the concrete dries quickly and shrinks before it is strong enough to resist cracking. Measuring relative humidity, ambient temperature and wind velocity at the pour site before the concrete is placed can help prevent this frustrating and expensive problem. Bluetooth® data transfer capabilities send minute by minute conditions during any pour straight to a laptop for easy jobsite documentation that conditions were within industry acceptable standards. The Kestrel 4300 Construction Pocket Weather Tracker is the perfect solution-accurate, quick response readings give concrete professionals the...

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Preventing Plastic Surface Cracking

 http://www.concreteconstruction.net/concrete-construction/preventing-plastic-surface-cracking.aspx Some Midwest ready-mix producers report there have been more problems associated with plastic shrinkage in concrete this past spring. Dave Polosa, owner of Polosa Cement Contracting, Tinley Park, Ill., says that he has experienced shrinkage on his jobsites eight times so far this season. His company installs decorative concrete primarily in residential settings with most of his work involving applications of color hardeners or integrally colored concrete slabs. He notes that jobsites with southwestern exposures are the most prone to problems because that's the direction that most winds come from in his area. The ACI nomograph was first developed...

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