Do the names R. E. Davis, R. W. Carlson, and L. H. Martin mean anything to you? They were researchers working for the U.S. Bureau of Public Roads (now the Federal Highway Administration) in the 1930s.
They were investigating ways to improve the durability of concrete, especially in cold climates that are subject to freeze-thaw cycles. Their work led to the development of air entraining admixtures that are commonly used in the concrete industry today.
Air entraining admixtures create small air bubbles within the concrete, significantly enhancing its resistance to freeze-thaw damage and improving its overall durability. How?
As water freezes, it expands by approximately 9% by volume, causing pressures that can rupture concrete and cause scaling. Air-entraining admixtures create microscopic air bubbles within the concrete, providing space for water to expand when it freezes. This reduces internal pressure and prevents cracking & spalling in freeze-thaw conditions.
Read more about air entraining admixtures, and the benefits, as well as drawbacks of using them at: https://lnkd.in/eWFmHi5F
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Technical Director at Koster Aquatecnic LTD. Designers and suppliers of Basement and flat/green roof waterproofing solutions.
2wYou are 100% correct Simon. As a manufacturer and designer of basement systems we see it time and again where the contractor has taken it upon themselves to change the waterproofing (Basement or Roofing) design, generally as a value engineering exercise. These cost reducing measures normally also reduce the level of protection originally offered, They tend to be installed by persons who are not trained or deemed competent to install the system and that is where the cracks begin to show. Designing of a basement is not easy, it also takes a good amount of time to come up with a robust system(s) which will work. There are so many things to consider which often are overlooked in the pursuit of saving money through CDP. I strongly believe that contractors should tender with the original design and that architects/engineers should remove the option for CDP when putting packages together. Although i do relish the challenge of problem solving failed basements, it would be fairer and cheaper to get it right the first time! While we are on the topic, the statement "Equal or Approved" leads to almost as many failures.....perhaps a post for another time?