Contract Compliance Vs. Operating Range

One of our readers was recently looking for the difference between Contract Compliance and Operating Range.  This terminology is used for various aggregate products and in the past was used in the old section 39 of the Caltrans May 2006 standard specifications.  It no longer exists in the 2010 version of Caltrans' Standard Specifications for HMA but if you are running a job based on older specifications it can be quite confusing.

In the May 2006 Caltrans Standard Specifications for section 39-Asphalt Concrete, there were three columns of gradation ranges for each type of asphalt concrete.  The first column is "Limits of Proposed Gradation" which is for use when creating a mix design.  The combined gradation of your mix components must be within these ranges when you decide on your bin and/or feeder percentages for your mix design.

The second column is "Operating Range".  The operating range is the range that you should be producing in during the production of your asphalt concrete.

The third column is "Contract Compliance".  This column is a larger range than the Operating Range and is used to basically give you a fudge factor for not having to shut the job down or pay a deduct.  If your gradation is outside of the Operating Range but within the Contract Compliance requirements, you can continue paving for the rest of the day.  It should be noted though, that even though you're within the Contract Compliance requirements that you will still need to make changes by the next paving day to get your material back into the Operating Range or you may be forced to stop paving until you can.

If you have a test result that is outside of the Contract Compliance requirements Caltrans generally has the right to ask you to remove and replace it or charge you a payment deduction.  The same rules for Operating Range and Contract Compliance that I mentioned above apply to aggregate products such as base rocks.

I hope that answers your question anonymous user!  Feel free to post any of your questions, no matter how small, in our discussion forum to get the answers you need!