Separation and Recovery of Aggregate from Asphalt Pavement Wastes Using High-temperature and High-pressure Water

Abstract

The recycling ratio of reclaimed asphalt pavement (RAP) reached about 99% in 2002, the highest for any industrial waste, a clear sign that recycling efforts are actively applied in the road pavement fi eld. Even more effective use of resources and materials will require the incorporation of environmentally-friendly processes over the entire cycle. It is also necessary to establish a pavement recycling system that can cope with the diversifi cation of pavement materials and reclaimed materials, such as modifi ed reclaimed materials, of which production of which is predicted to increase. This study proposes a pavement recycling technique in which high-temperature and high-pressure water is used to separate and recover aggregate and asphalt binders in RAP for reuse. The removal performance of two types of deteriorated asphalt binders was evaluated. The properties and quality of separated and recovered aggregate were also tested to examine the suitability of the recovered aggregate as pavement. The tests and analyses showed that high-temperature and high-pressure water was very effective for removing deteriorated binders and modifi ed binders. High-temperature and high-pressure water is an environmentally friendly recycling technique with great potential and repeated reuse of recovered aggregate is feasible.

Extraction of Asphalt from Asphalt Concrete Using Subcritical Water

“…Few pieces of research have investigated the application of subcritical water to the recycling of asphalt concrete. In one study, Kano and colleagues successfully removed asphalt from asphalt mixture using hightemperature and-pressure water [Kano, Akiba, and Kuriyagawa 2006]; in another, asphalt was shown extractable from asphalt concrete using a Soxhlet extraction set-up ].…”