Louisiana's current statistically based specification system was initiated in 1967. This system was based upon contractor quality control and department acceptance testing using known variability concepts. A materials data base was also initiated at that time to archive materials test results and information. Since inception of the data base and system, major changes have been incorporated into the standard specifications. Further, there have been advances in equipment and operational control devices that can further reduce construction and test variation.
With these changes in mind and the presence of an excellent data base for analysis, this study was directed at updating the system to reflect current operations and to exert pressure for quality improvements where this was practicable. The study began with a statistical analysis of the data, collected for various plants and mix types and proceeded to establish a framework for revision of the specification and quality control system. Its conclusion will be with recommendations for changes that would facilitate the improvement of overall quality of the hot-mix asphaltic concrete.
It is believed that the procedures used, experience gained and knowledge developed by involved personnel will assist those with similar problems in reaching results which improve operations and quality of the final product in a timely manner.