Estimation of Reclaimed Asphalt Pavement Binder Low-Temperature Properties without Extraction

Abstract

The use of reclaimed asphalt pavement (RAP) as a component of asphalt mixes is a common practice. Generally, the use of RAP is expected to reduce the total cost of pavement construction, conserve natural resources, and protect the environment. However, estimating the properties of the aged binder in RAP is a challenging problem. Extraction and recovery of the binder is the current method used to estimate these properties. The unknown effects on the binder properties of using solvents to extract and recover the binder are a concern; thus, development of new methods to estimate the RAP binder properties without altering them is necessary. Introduced is the development of a new testing procedure to estimate the low-temperature properties of the RAP binder without extraction or chemical treatments. The testing procedure uses the Superpave® bending beam rheometer (BBR) with minor modifications. Fresh binder and fine RAP materials mixed with fresh binder (referred to as RAP mortar) are tested in the BBR, and properties of the RAP binder are then estimated from the binder and mortar properties. The developed testing procedure went through several testing stages for selection of testing parameters, such as the RAP gradation to be included in mortar, testing load, and binder content. The final procedure developed was then verified, and its capability of capturing the aged low-temperature properties of the binder in RAP materials was confirmed.