Development of Quality Control/ Quality Assurance Specifications by Using Statistical Quality Assurance for Asphalt Concrete Pavements in California

Abstract

Since 1992, the California Department of Transportation (Caltrans) has been working to improve quality in construction contracting and ultimately the quality of the product provided to the public. In 1996, Caltrans implemented quality control/quality assurance (QC/QA) specifications for asphalt concrete paving. These specifications require contractor QC and provide rewards or penalties based on statistical quality analysis of eight quality characteristics. These specifications were developed through a joint Caltrans/industry group and are supplemented with a QC manual. They were introduced through presentations to user/producer groups, appointment of district QC/QA coordinators, and training for engineers. In March 1996 the first project using QC/QA specifications for asphalt concrete went to bid and in the first year six projects were completed with them. Early projects were for the most part successful. Throughout 1996-1997, the specifications, the QC manual, and the implementation program were reviewed. Revisions to the specifications have been developed. The specifications and manual, issues, recommendations based on the 1996 projects, changes Caltrans has made for the continued use of QC/QA for asphalt concrete, and anticipated additional endeavors in the areas of QC/QA and materials testing are discussed here.