Louisiana's current statistically based specification system was initiated in 1967. This system was based upon contractor quality control and department acceptance testing using variation known concepts. A materials data base was also initiated at that time to archive materials test results and information. Since 1971, a series of changes have been incorporated into the standard specifications. Further, there have been advances in equipment and operational control devices, both intended to improve construction quality and reduce variability. With these changes in mind and the presence of an excellent data base for analysis, initial effort has been directed at analysing the system to quantify current quantify current characteristics of the production of asphaltic concrete. The study began with a statistical analysis of the data on Marshall stability and compacted density for various plants, mix uses and types. The data was reviewed against specification requirements and the penalty payment scheme. The paper concludes with recommendations for an approach to changes to the specification to improve overall quality of the asphaltic concrete. (A)
Abstract