Concrete Admixtures that Control CrackingReducing Drying or Shrinkage CrackingHydrated cement paste shrinks as it loses moisture from its extremely small pores. As the moisture is lost in these small pores, the surface tension of the remaining water tends to pull the pores together which results in a loss of volume over time. Shrinkage reducing admixtures (SRAs) are designed to decrease the effects of drying shrinkage by reducing the surface tension in these pores. It should be noted that the type of aggregate and the cement properties themselves can influence the amount of cracking that can occur. Thus, it is important to test local project-specific materials if doing shrinkage testing. Curing also affects cracking. In slabs, the top tends to dry out first and shrinks while the lower sections still have a higher moisture content. This difference in moisture can be altered by use of Shrinkage Reducing Admixtures, which alter the way water migrates through the concrete and results in a more uniform moisture profile. Find Concrete Admixture Suppliers See also: Return to Concrete Admixtures Find a Concrete Contractor 24 Services in 221 Metros -- U.S. and Canada © 1999-2009 ConcreteNetwork.com None of this site may be reproduced without written permission |
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