Improving DMS 9210 Requirements for Limestone Rock Asphalt - Year One Interim Report.

摘要

Limestone Rock Asphalt (LRA) mixtures have been produced and placed for several decades using specification requirements currently listed under DMS 9210. Several Districts have had placement issues and premature failures at the beginning of 2010. These issues and failures have been attributed to material properties. Requirements for DMS 9210 have not changed for several years and need to be evaluated to possibly produce a higher quality material to reduce the occurrence of premature failures and to minimize placement issues. The objectives of the study are to (1) Evaluate specification requirements of Item 330 and DMS 9210, (2) Conduct field evaluations and lab testing to determine workability and acceptability as stockpile material for use as needed in pavement maintenance, and (3) Consider improvements to the specification requirements to ensure an acceptable and workable stockpile material for up to 6 months. Twenty eight test patches were constructed around the state but none of the performance problems seen in 2010 were observed in the test sections. A review of production data indicates that one of the suppliers made some significant changes to the flux oil content during the time when the 2010 performance problems were noted. Tests have been identified in this Year One study which may be better indicators of LRA field performance. These tests are being fully explored in Year Two to determine their sensitivity to flux oil content and type.