Reclaimed Asphalt Compaction

[bank]

We will be using reclaimed/recycled asphalt base in a parking lot. The question was asked if ASTM D698 would be appropriate for testing the compaction. If not, can someone tell what the appropriate specification would be?

Thanks in advance.

 

[cvg]

Here is a spec I have used which includes both proctor test and proof rolling. This was for the finished surface gravel road, no AC or concrete over the top:

3.11 Access Road Surfacing
A. Subgrade shall be moisture conditioned and prepared as necessary to meet the final surface performance specified under paragraph D of this subsection.
B. Placement shall be by methods that will minimize segregation. Any damage to underlying or surrounding material or structures during placement of the millings shall be repaired before proceeding with the work.
C. Asphalt millings shall be placed to full layer thickness in one operation in such a manner as to minimize segregation and avoid damage to underlying materials.
D. Asphalt millings shall be road mixed with an emulsion/rejuvenator application rate of 0.25 Gal/SY – Inch. The mixed asphalt millings shall have a total moisture content of 6% by weight and be compacted to 95% of Standard Proctor Density.
E. Compaction shall be achieved by a smooth drum vibratory compactor, or other equipment approved by the ENGINEER. Roller shall make a minimum of three passes in each direction over the asphalt millings. Roller direction shall be in both the longitudinal and lateral direction .(perpendicular to the centerline of the road). Prior to acceptance, the surface of the placed asphalt millings shall be proof-rolled and shall be smooth, firm and unyielding. At the completion of this activity no wheel ruts or other irregularities shall remain on the surface. Place asphalt millings to the lines, grades, cross sections, and dimensions shown on the drawings.

 

[Ron]

Yes, D698 can be used; however, for base material I would use a higher compaction standard such as D1557, the modified Proctor.

Also, determining the actual moisture content of milled asphalt is a bit tricky. You can use a nuclear moisture gage or a Speedy Moisture Meter (calcium carbide type), but both should be correlated to a laboratory method...that's where there's a problem. Oven drying doesn't work well with asphalt materials, even weathered ones. It drives off volatiles and gives an erroneously high moisture content.

Use one of the asphalt material moisture determination methods, but typical testing labs don't have the equipment or the expertise to do these tests. Hopefully your local lab can do them or can work through an equivalence by doing several extractions to determine the asphalt content and then applying a correction after drying.

 

[bank]

Thanks guys. TxDOT apparently has procedures for laboratory testing and field testing of reclaimed asphalt, and it was decided that those would be the ones to use.

You've been very helpful.