The project is complete.  The researchers concluded that mechanical devices can be use to measure and calibrate Blaine cells with sufficient precision to allow users to conduct measurements without the need to handle mercury, and proposed changes to AASHTO Test Method T 153 to allow use of physical measurements.  The report has been forwarded to AASHTO staff to make it available to the chair and members of the AASHTO Highway Subcommittee on Materials, and to consider adoption of the recommended changes.  (NCHRP staff: A. N. Hanna).