Click to download 1-page FHWA Flyer (PDF)
One of the Federal Highway Administration (FHWA)’s Mobile Concrete Technology Center (MCTC)’s recently released a one-page technology transfer flyer that covers air-entraining admixtures for concrete. It describes what chemical air-entraining admixtures are and what they do.
Simply, air-entraining admixtures help form air bubbles—they facilitate the development of a system of microscopic air bubbles within concrete during mixing—that impart several important features of concrete:
• Increase the freeze-thaw durability of concrete
• Increase resistance to scaling caused by deicing chemicals
• Improve workability
• Reduce concrete strength.
As a general rule, a 1% increase in the concrete air content will decrease the 28-day compressive strength by about 3 to 5%.
The tech flyer also describes:
• Why air is important to good quality concrete
• What the difference is between air entrainment and encapsulation
• How air-entraining admixtures work.
This information-packed document also describes the chemistry and classification of admixtures and the effect of materials and practices on air entrainment. There’s also a section that summarizes the specific ways the air-entrainment admixtures improve concrete durability.
Checklists and a table provide quick reference points and make the information even more accessible and easy to use. Whether you’re a seasoned concrete professional or relatively new to the business, this is a good resource for contractors, agency personnel, engineers, and others focus on placing durable concrete pavements.
To download a copy of the flyer “Air-Entraining Admixtures for Concrete”, please click on image at top, or go to: www.fhwa.dot.gov/pavement/concrete/trailer/resources/hif20085.pdf