Most local jurisdictions use Caltrans specifications. In southern California, the Greenbook is commonly used. (See Greenbook discussion below.) Where RAC is allowed, it must also, of course, meet the same grading and quality requirements as virgin AC.

Caltrans Specifications--Procedures
Caltrans takes a new "spec" through three stages:

1.  Special Provision (SP). First it is an SP where it is used initially on a number of projects.

2.  Standard Special Provision (SSP). After the SP has been used successfully for a period of time, then it usually becomes an SSP which means it is a method approved by Caltrans.

3. Standard Specification. After the SSP has been used successfully for a period of time, then it usually becomes a Standard Specification, and is included in the Caltrans Standard Specifications which is published every four years. The latest edition using English measurements is dated July 1992. A metric edition was published July 1995; all subsequent editions will be metric. The next edition is anticipated in 1998 or 1999.

Caltrans Specifications--Pending
Caltrans specifications for two AC processes are being modified: "Hot Recycling at a Central Plant" (25-50 percent recycled) and "Cold, In-Place" (100 percent recycled). The specifications are expected to be completed in 1997. Temporary versions are currently being used in Caltrans projects, and are available to local governments and the public through Caltrans.

Caltrans Specifications--Future
Caltrans is investigating various technologies for future specification:

Stockpile Study.  Caltrans is doing a "pilot study" to determine the feasibility of using up to 15 percent RAP from contractor-generated multisource stockpiles. Progress has been slow in this area because few projects have been constructed using this type of recycling. The evaluation period will continue at least through the 1997 construction season.

Microwave. One company produces 100 percent RAC by using a patented cool flow and microwave process to reheat it. Caltrans completed the second test project with this technology in the summer of 1995 using up to 70 percent RAP. Results have been evaluated. Although the process looks favorable, the recycle mix did not meet Caltrans芒?＆#8482; specifications on this project.

Hot, In-Place. Caltrans also tested hot, in-place AC recycling on two projects. A recycling agent was used to rejuvenate the old asphalt. Up to 15 percent new AC was added in some sections; the new AC is 100 percent recycled. The process is available as a "Special Provision." However, the results are inconclusive, so they classify the method as experimental, which means that Caltrans does not use the procedure routinely. Caltrans plans to use this type of recycling on future test projects.

Greenbook Specifications
What is the Greenbook? The Greenbook is another name for the Standard Specifications for Public Works Construction, and is used by the City and County of Los Angeles and 200 other local governments and agencies in the Los Angeles area. It is published by the Joint Cooperative Committee of the Southern California Chapter of the American Public Works Association, and the Southern California Districts of the Associated General Contractors of California.

The Greenbook is updated and republished every three years. Supplements are published yearly. It includes English and metric units, and is available through:

BNI Building News
1612 S. Clementine St.
Anaheim, CA 92802
(714) 517-0970.

RAC Specifications. The Greenbook has specifications for "Recycled Asphalt Concrete--Hot Mixed" in Section 203-7. Methods are outlined for batch plants and drier-drums. Up to 15 percent of RAP is allowed in the virgin mix. Larger percentages of RAP are allowed if test data is submitted to the Chief Engineer of the Agency.