CT 229 Changes-June 2011

Caltrans has issued a new version of CT 229: Method of Test for Durability Index.  There were very few changes but below are the ones I thought were worth mentioning:

• The test method has been changed over from metric to US units.
• The specifications for the the lateral reciprocating motion of the coarse aggregate agitator have been changed from 4.75 ± 0.17 Hz to 285 ± 10 cycles per minute.  This is due to the change from metric to US units.
• The detailed specifications on the mechanical sand equivalent shaker have been removed and the test method now refers you to the apparatus used in CT 217.
• It no longer specifies the sand equivalent test apparatus.
• You can no longer use tap water in this test, even if it does not affect the test results.  The only exception is that you may use tap water during the rinse process.

The June 2011 version of CT 229 can be found on the Caltrans website and at: CT 229-June 2011

Good luck and happy reading!