This site is dedicated to topics of interest to our members, their employees, and other interested parties. We encourage our readers to submit any questions or points of view that may be of interest to others. Answers have been prepared and submitted by CCTIA members and are the opinion of the author. The answers do not represent an official position of CCTIA. For comments or questions, please contact us.
|
10.004 7-Day Concrete Strength is a Percentage of What? |
||
| Q |
Our testing laboratory routinely supplies our customers with 7-day concrete break results. At what percentage of the specified strength should we state there might be a problem with the final result? -- Unknown |
|
| A |
07/28/05 - Response prepared
by Jeffry Cannon, Laboratory Manager, Kleinfelder, Inc.,
Sacramento, CA |
|
| Different
concrete mixtures will gain strength at different rates, so there
is no universally applicable rule about what a 7-day strength
versus 28-day strength ratio will be. This is also true because
of the numerous types and brands of cement, and the hundreds of
different admixtures routinely used in concrete today. But as
a general rule of thumb for normal-weight concrete that does not
contain unusual ingredients, 7-day strengths that are less than
65% of the required 28-day strength should warrant close attention. NOTE: If the concrete mix contains fly ash, especially large amounts of fly ash, strength gain will be slower than mixes that do not contain fly ash.
|
||
-
If you would like to add your comments to this question or the response given, please email us at info@cctia.org
home - who we are - guidelines for special inspection - structural tests and inspection schedule - meeting schedule Please send your comments and questions regarding this website to the webmaster.