UC Davis Institute of Transportation Studies

A rubberized asphalt chip seal project on SR-86 in District 11 exhibited flushing and rutting shortly after construction. These defects occurred within the 1-year performance warranty period specified in Section 10-1.22 of the Special Provisions of Contract No. 11-241104. Results of California Test 342 performed by Caltrans have confirmed that the coefficient of friction for the flushing segment were less than 0.30, which is less than the minimum required by contract. The contractor refuses to perform the specified repair at contractor�s expense, saying they followed Caltrans specifications and, therefore, are not responsible for a defect due to an "inadequate specification" (given the project condition). On Dec. 17, 2004, Caltrans Headquarters Maintenance and the Pavement Research Center agreed on a study to address the following four objectives:

* Investigate if the causes of failure of the asphalt rubber chip seal project in District 11 can be determined. o Determine compliance with prescriptive specifications and relate prescriptive specifications to failure or success. o Collect test and construction records and investigate if the cause of failure can be determined. o No lab testing is required unless it is apparent that lab testing will help determine causes of failure. Lab testing will be subject to costs and scheduling constraints, availability of resources, and further discussion. Core samples collected to perform lab testing by Caltrans District 11. * Determine the effectiveness of the materials and workmanship warranty on this project. o Critique the concept of combining prescriptive specifications and performance criteria and provide a preliminary statement about the efficacy of combining these criteria. * Evaluate and critique the planned 2-year performance warranty if the cause of rutting and flushing is identified. * Determine whether the Department should move toward performance warranties instead of materials and workmanship based on discussions with various experts and available information. Note: Gerry Huber (Heritage Research Group) and Steven Krebs (WI DOT) have agreed to provide advice. Other sources for advice suggested by Shakir have not yet responded at the time of this writing.