Concrete, the most widely used building material in the world, can be very temperamental in certain weather conditions. Due to its poor tensile strength, concrete is almost always certain to crack, but professionals do their best to reduce the size and delay their appearance. A new app is hoping to reduce the risk of concrete, plastic shrinkage by monitoring weather patterns.
Plastic concrete shrinkage occurs within the first few hours of placing concrete, when the concrete has not yet developed substantial strength. These types of cracks are typically wider and deeper than other early cracks, as they can be between 2 to 4 inches deep and around 1/8 inch wide. In order to prevent plastic cracks from forming, the air temperature, humidity, and wind has to be monitored and adjustments then have to be made. Plastic cracks typically form in hot weather conditions, as the water toward the top of the concrete evaporates very quickly, but can also occur in cold weather situations, when the concrete is much warmer than the air temperature.
The Plastic Crack Risk Calculator, a free created by former superintendent and current professor at Southern Illinois University Mark Grinter, takes the guess work and hassle out of determining plastic crack risk on your projects by pulling weather data from the National Oceanic and Atmospheric Association and comparing that data to evaporation-rate nomographs, which determine how fast water will evaporate. By simply entering your project’s zip code, the app then determines if your site is at a low risk, moderate risk, or high risk for plastic shrinkage for the next 7 days, shown just like in the picture at the top of this article.
The app even lets you set up an account to receive email notifications when weather conditions reach “high risk” levels. Currently, it's only available as a web application which can be accessed from any web browser.
Plastic Crack Risk Calculator | University of Southern Illinois
We’ve mentioned it over and over again, but construction rework is expensive, time consuming, and wasteful. This is especially true when the rework involves the world’s favorite building material, concrete; as hard as it is to put in, it’s even harder to take out. Because of that, it’s extremely important to develop good practices to spend time planning before a concrete pour.