Wednesday, February 27, 2013

New Section 39 RSS Released (2/22/13)

Caltrans released another Revised Standard Specification (RSS) on 2/22/13, outside of their normal once per quarter release schedule.  Included were many changes to section 39, most revolving around RAP.  Here are a couple of the major changes:
  • You are now allowed to use up to 25% RAP by total weight of aggregate in your dense hot mixes (as opposed to 15% in the past)  RAP is still not allowed in Open Grade or Rubber mixes.
  • If you decide to add more than 15% RAP to your mix you will now be held to additional requirements including:
    • Quality standards to meet Hamburg Wheel Track Test and TSR specifications
    • A quality standard to keep the binder content of your RAP within 2% of your average RAP binder content
    • A quality standard to keep the RICE value of your RAP within 0.06 of the average RAP RICE value
    • Additional sampling requirements which require 1 sample of each RAP product to be sampled every 1000 tons of crushing, a minimum of 6 per stockpile. If the RAP is augmented, the spec requires that you increase this to 1 sample of each RAP product to be sampled every 500 tons of crushing.
    • You must fractionate your RAP into two different products, separated on the 1/4" sieve
    • You must sample and test the RAP gradation when you are producing hot mix twice per day as opposed to once per day with less than 15% RAP.
    • You may only adjust your RAP feeder settings by ± 3% as opposed to 5% if you have less than 15% RAP.

  •   There are now additional cases where you will now need to submit a new JMF including:
    • If you change the substitution rate by 3% or more (5% for mixes with less than 15% RAP)
    • If the average binder content of your RAP changes by 2% or more
    • If the RICE value of your RAP changes by 0.06 or more
  • The specification now not only designates the allowed substitution rate by weight of aggs, but also regulates the maximum binder replacement.  This value is different for surface courses (25% of OBC) versus leveling courses (40% of OBC).
  • If you replace more than 25% of the optimum binder content in your mix with RAP you will now be required to use a softer binder with the PG grade upper and lower temperature classifications reduced 6°C from the specified binder.  For example if the specifications specify PG 64-16 you will now be required to use a PG 58-22.  You are also allowed to request this change if you add any RAP at all in your mix.
In non-RAP related changes:
  • VMA, VFA, and DP are now report only.
  • In QC/QA jobs you are now only required to test your mix for CT 371 every 10,000 tons instead of 5,000 tons.  These results are still report only unless you have greater than 15% RAP in your mix.
As you may know, you can view red lined copies (including the RSS changes mentioned in this post) of the 2010 Standard Specification's Section 39 on our website at the tab above labeled "Caltrans Section 39 Updates".  I highly recommend you read over the 2/22/13 RSS changes since there are so many large ones this time.

Good luck!

No comments:

Post a Comment