What we are doing about COVID-19

Contact Us

Fill out the form below to request more information from our Bladensburg location.

    View our privacy policy

    MD: Bladensburg (HQ)

    (301) 927-8300

    4700 Annapolis Road, Bladensburg, MD 20710, USA

    Mon-Fri 6:30AM to 4:00PM Saturday 6:30AM to 12:00PM Sunday CLOSED

    Get In Touch with someone at MD: Bladensburg (HQ)
    (301) 927-8300

      Response time within 4 hours

      Plastic Shrinkage Cracking

      David Welch | August 27, 2015

      Plastic shrinkage cracks appear in the surface of fresh concrete soon after it is placed and while it is still plastic. These cracks appear mostly on horizontal surfaces. They are usually parallel to each other on the order of 1 to 3 feet apart, relatively shallow, and generally do not intersect the perimeter of the slab. Plastic shrinkage cracking is more likely to occur when high evaporation rates cause the concrete surface to dry out before it has set.

      Plastic shrinkage cracks are unsightly but rarely impair the strength of concrete floors and pavements. These cracks, however, can permit the ingress of other aggressive chemicals that impact durability and as weak points for the initiation of later age cracking due to other reasons. The development of these cracks can be minimized if appropriate measures are taken prior to and during placing and finishing concrete. Note:

      Plastic Shrinkage Cracking in Concrete - Causes and Prevention | For Construction Pros

      Source: ACI 305R-10, Guide to Hot Weather Concreting

      How to Use:

      1. Begin with air temperature and move up to the relative humidity
      2. Move right to concrete temperature
      3. Move down to wind velocity
      4. Move left to read approximate rate of evaporation

      Whenever the chart predicts water will evaporate at a rate approaching 0.2 pounds/square foot/hour (lbs./sq. ft./hr.), the likelihood of plastic shrinkage cracking exists. Of course, other factors, such as elevated air content in the concrete or the presence of fly ash or microsilica, also affect the occurrence of plastic shrinkage cracks. However, ACI’s nomograph is a pretty fair indicator for everyday concrete.

      What can you do to minimize plastic shrinkage cracking

      • Dampen the subgrade and forms when conditions for high evaporation rates exist.
      • Prevent excessive surface moisture evaporation by providing fog sprays and erecting windbreaks.
      • Cover concrete with wet burlap or polyethylene sheets between finishing operations.
      • Use cooler concrete in hot weather and avoid high concrete temperatures in cold weather.
      • Cure properly as soon as finishing has been completed.


      Need a more accurate estimate on the evaporation rate? Check out the ACI Mobile app

      Ready Mix Sales ManagerDavid Welch

      MD: Annapolis Junction

      Latest News

      Ernest Maier and Gomoljak Counter Price Sheet

      Ernest Maier and Gomoljak Counter Price Sheet

      Pricing accurate as of 10/6/2021 and valid for Annapolis, Bladensburg, and Gaithersburg locations (contact us for bulk pricing and delivery): […]

      Read More
      How to Speak Stone

      How to Speak Stone

      Natural stone is a beautiful product. As with anything created by nature, it is highly variable. With so many classifications […]

      Read More
      Cold Weather Concreting

      Cold Weather Concreting

      While it gets cold in the winter, that doesn’t mean you have to stop concrete form work. Taking the right […]

      Read More
      Cost-Effective Masonry

      Cost-Effective Masonry

      If you want to build cheap you use wood, if you want to build to last you should use masonry. […]

      Read More