CALIFORNIA'S INTERSTATE-710 REHABILITATION: MIX AND STRUCTURAL SECTION DESIGNS, CONSTRUCTION SPECIFICATIONS (WITH DISCUSSION AND CLOSURE)

In California, as elsewhere in the United States and overseas, the necessity to design and construct asphalt pavement structures which exhibit service lives greater than the approximately 20 years, for which many pavements have been designed in the past, are major objectives of organizations both public and private. This paper presents the results of both mix and structural designs for a full-depth asphalt concrete (AC) replacement structure and an AC overlay on a cracked and seated portland cement concrete (PCC) pavement. These designs have been developed for a major facility in the Los Angeles area, the Interstate-710 freeway from the Port of Long Beach, California, inland to the east. For the full-depth AC replacement structures, required in order to increase clearances between the freeway and the overcrossings, both mix and structural design methodology are described. Thickness for the AC structure on the cracked and seated PCC pavement is based on the consideration of the influence of reflection cracking. Successful performance of the longer-life pavements requires strict attention to pavement construction. Discussion is directed to some changes to the current California Department of Transportation (Caltrans) specifications and construction practice to achieve this improved performance. The resulting designs represent the partnered effort between Caltrans, the Asphalt Industry in California, and the University of California, Berkeley, through the Longer Life Asphalt Pavement Task Group of the Pavement Design and Rehabilitation Committee of Caltrans.