The difference in performance appears related to the angularity of the coarse aggregate. Coarse aggregate in mainline was not as highly crushed as coarse aggregate in curves. The fine aggregate was highly crushed. Heritage is performing testing on cores from several sections. More data will be presented at the next ETG meeting.
Some testing is complete.
Several ETG members indicated a continuing concern with the fine aggregate angularity requirement. The criteria was based on the best engineering judgment at the time. The ETG can recommend changes with sufficient supporting data. Members of the aggregate industry were asked to provide the ETG with a summary. Dale Decker presented NAPA's Implementation Update.