Development of new mix design for cold in-place recycling using foamed asphalt.

摘要

A desire to maintain a safe, efficient, and cost-effective roadway system has led to a significant increase in the demand to rehabilitate the existing pavements. Asphalt pavement recycling has grown dramatically over the last few years as the preferred way to rehabilitate existing asphalt pavements. A number of different techniques has been employed in the rehabilitation of existing asphalt pavements. One of these is Cold Inplace Recycling with foamed asphalt (CIR-foam). However, the current CIR-foam practice utilizes a generic recipe specification without a mix design, where a contractor is given latitude to adjust the proportions of the foamed asphalt content to achieve a specified level of density. Therefore, this study was conducted to develop a consistent laboratory mix design in consideration of its predicted field performance. First, the CIR-foam mix design parameters were identified and a new laboratory mix design procedure of CIR-foam mixture was developed. The developed mix design procedure was then validated using different sources of RAP materials. The simple performance tests, which include a dynamic modulus test, a dynamic creep test and a raveling test, were used to evaluate the consistency of a new CIR-foam mix design process to ensure reliable mixture performance over a wide range of traffic and climatic conditions.