Development of Asphalt Cushioned Plastic and Plastic Reinforced Asphalt Membranes for Seepage Control (Project Completion Report)

Abstract

This project was concerned with laboratory equipment development, laboratory testing, construction equipment development and field investigation of the APAC (Asphalt-Plastic-Asphalt-Chip-Coated) water seepage barrier. The laboratory equipment that was designed and fabricated for the project included hydrostatic testing vessels, slope stability apparatus, and tensile testing grips. Three testing methods were utilized and evaluated in the APAC investigation. The first test method evaluated the hydrostatic puncture resistance of the asphalt-polyethylene combination. This test confirmed the hypothesis that the asphalt effectively increases the puncture resistance of the APAC membrane over that of plain polyethylene. The second test investigated the slope stability of a protective APAC chip seal. It was found that a typical 3/8 in. (9.5 mm) cover aggregate remained stable on constructed slopes of 3:1 and 4:1 and that the 2:1 slope remained stable up to a surface temperature of 1220F (500C). The third test method evaluated adhesive materials and indicated that Presstite mastic was the best suited adhesive for sealing polyethylene overlaps. Subsequent field investigations resulted in equipment development that increased construction efficiency in the installation of the APAC membrane. Actual completed field installations were evaluated and further recommendations are included.