Construction of 2014/15 County-Wide HMA Overlay SAMI Project

Construction of 2014/15 County-Wide HMA Overlay SAMI Project By TRANSPORTATION DIVISION County of Santa Barbara, Department of Public Works For League of California Cities January, 2016 Introduction The purpose of this project was to pave fifteen roads that are located across the County of Santa Barbara. A total of eighteen lane-miles were resurfaced of the total 3,376 lane miles within the County. The principal strategy for restoring these roads centered on grinding the old asphalt to a depth of nearly two inches. After grinding a one-half inch thick layer of recycled asphalt rubber seal coat was applied, followed by a three inch layer of type A hot mix asphalt. The recycled rubber seal coat acts as a cushion between the distressed older pavement and the new overlying pavement. This asphalt rubber stress absorbing interlayer (SAMI) was placed on all roads in the project. In addition, excessively cracked asphalt areas comprising 38,113 square feet or 4 percent of the project area of 925,209 square feet were dug-out and rebuilt prior to repaving. Stress Absorbing Membrane Interlayer The SAMI was placed to seal the existing cracks below the fresh asphalt and retard future reflective cracking in the fresh asphalt. This innovative layer includes ½-inch aggregate placed over 0.5 gallon per square yard of binder. The SAMI flexes with the pavement, adds structure, and improves rideability, thus, extending the life of the pavement. This layer also waterproofs and crack seals any imperfections on the old pavement surface. Also included was the construction of a 5-foot wide paved multi-use pathway for walking, jogging and skateboarding. These safe and community improvements serve the multi-nodal transportation needs of residents, school children and nearby businesses. The improvements supplement an important pedestrian and bike paths between multiple communities within the County. Shoulder Backing Repairs An important component of the project included the placement of compacted granular material for shoulder backing. A total of 48,500 linear feet was placed which was 51 percent of the total 93,372 lane feet paved in the project. Shoulder backing provided conformity to the native shoulder materials on mountainous roads. Roadway Safety Repairs for Bicycle One of the unique features of this project was placement of asphalt swale along this portion of the Coastal Bike Route. The existing roadway is a two-lane roadway with significant elevation difference along the bikeway and the dirt shoulder. This swale decreased the shoulder transition from the roadway to the shoulder to increase bicycle safety. Roadway Safety Repairs for Pedestrians The Santa Barbara County Public Works Department sought to address all the issues facing residents, businesses and school children who frequent the area. Construction of a 5-foot wide paved multi-use pathway for walking, jogging and skateboarding was needed at this choke point on Hollister Avenue. Walkway is near the t