Working with Cement in Hot Weather Conditions

Construction work can be very difficult under the best of circumstances, including the use of certain materials such as concrete. Concrete is a building material that can be used in all types of weather throughout the year. However, in hot weather your workers must handle the concrete with enough care and protection so as not to run into any problems.

During hot-weather concreting, temperature is one problem; relative humidity and wind speed are the other components to the problems you may face. Experience has alerted us to the effects of hot weather on fresh concrete, such as:

  • Increased water demand in the mix
  • Rapid slump or workability loss
  • Rapid stiffening or actual setting
  • Development of surface plastic shrinkage cracks, and
  • Fluctuation in a downward trend of air content

Hot weather concreting may have a higher water requirement to maintain the workability, mainly due to the rapid hydration and evaporation, which occurs between batching in hot weather and on site delivery. A mix design performing well in moderate temperatures will need to be proportioned differently for hot temperatures. Remember, if you need more water, more cement material will also be needed to balance the increase in water.

As for the possibility of surface plastic shrinkage cracks and surface crusting from rapid surface evaporation, there are a lot of helpful procedures to protect your concrete in hot weather. The one item to focus upon is the use of a monomolecular film on the surface of the fresh concrete. The purpose of the monomolecular film is to reduce early evaporation of the surface water from sun and wind. A simple pump sprayer is the normal device to apply the product. Finishing and tooling are not interfered with and the tools can travel right over the liquid with no consequence. Consult a cement specialist for this, or other possible solutions.

Construction work is often done on a timely basis. Delays can cause even greater financial concerns and issues, so be sure to address these issues at a preconstruction meeting at the start of the project. Discuss potential issues and solutions with the engineer and the concrete producer. Also, be sure you construction insurance CT coverage is current and updated so that in the event of a potential loss or lawsuit, you are properly protected.