Hot Weather Concreting

Now that summer is here and more construction projects are getting underway, one consideration concrete contractors take into account is how higher temperatures and dry, windy conditions affect mixing, placing and curing concrete.  The American Concrete Institute (ACI) defines hot weather concreting as “one or a combination of the following conditions that tends to impair the quality of freshly mixed or hardened concrete by accelerating the rate of moisture loss and rate of cement hydration, or otherwise causing detrimental results: high ambient temperature; high concrete temperature; low relative humidity; and high wind speed.”   

Laboratory tests have shown that while concrete mixed, placed and cured during elevated temperatures develops higher early strengths, it can result in improper curing.  Also plastic shrinkage, which is the result of the loss of water from the surface of the concrete, is accelerated in hot temperatures, windy conditions and/or in low humidity.  When humidity is above 80%, plastic shrinkage is generally not a problem even in higher temperatures.    

One of the things that can occur when mixing and placing concrete in windy or hot conditions is the need for more water in the mix.  As the concrete may exhibit an increased rate of slump loss, the tendency is to add more water at the job site.  In addition there is the increased risk of plastic shrinkage and thermal cracking.  Another problem is it becomes harder to control the entrained air content of the concrete.  Furthermore, the increased rate of setting can make concrete more difficult to handle, compact, and finish and creates an environment that can result in a higher risk of cold joints.  

At The Conco Companies, our vast experience has given us the opportunity to place concrete under a number of climate conditions and specialized placement options.  Along with our highly trained, professional staff, we utilize the most leading-edge technology and equipment to offer customers the best quality results.

With Conco’s state-of-the-art concrete pumps and innovative methods we can handle the toughest challenges.   All of our highly trained pump operators are ACPA certified and our pumping division maintains an outstanding safety record. We understand the trust customers place in us once they choose our services, which is why we approach each project as a partnership from concept right through to completion.

Source: concrete.org/news/newsdetail.aspx?f=51687868