Thursday, June 21, 2012

CT 227 Changes-June 2012

Caltrans has come out with another version of CT 227 (last updated in March 2012).  The June version only had a few changes and a couple changes that look like they were only correcting a mistake made in the March version.  Below are what I noted as the important changes:

  • In the apparatus section it now specifies the type of graduated plastic cylinder as Assembly B, in Transportation Laboratory drawing No. C 218 as opposed to referencing CT 217.  (This drawing is not shown in CT 227 but is shown in CT 217)
  • Changed the name of “Stock Calcium Chloride Solution” to simply “Calcium Chloride Solution” in the materials section.
  • Now references which catalog numbers are applicable for “Sand Equivalent Stock Solution” in the materials section.
  • Tap water is once again allowed to be used in lieu of distilled or deionized water when proven to not affect the test results.  In addition, if during testing with tap water, a clearly defined line of demarcation does not form between the sediment and the liquid above it or if the cylinder is still darkly clouded after 20 minutes you will need to retest an untested portion of the same material using distilled or deionized water.
  • Temperature correction factors are no longer allowed.  Although the sentence is confusing, it seems that only test results that are achieved when the testing water is at 72˚F±5˚F are valid.

Happy Reading!

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