Refined decomposition: A new separation method for RAP materials and its effect on aggregate properties

Abstract

In order to high-content and high-quality use of reclaimed asphalt pavement (RAP), the separation of aged asphalt and aggregates in RAP is necessary. However, the current separation methods are either inefficient, unsafe or costly. The objectives of this study are to propose a new separation method named refined decomposition (RD) and evaluate its separation efficiency and effect on aggregate properties. Quantitative indexes of asphalt removal percentage and weight loss percentage were proposed through asphalt extraction test to evaluate the separation degree of asphalt and agglomeration degree of RAP. The morphological and mechanical properties of RAP aggregates recycled from RD process were evaluated by aggregate imaging measurement system and crushing value test. The results showed that the separation degree is about 30–45 % and the agglomeration degree is reduced by 20 % for coarse RAP using RD method. The improved stability of the processed RAP is observed as well. The strength of aggregates is slightly enhanced, the angularity is slightly reduced, and the sphericity and texture are scarcely affected after RD process. In view of the acceptable changes in properties of aggregates, the RAP materials from the efficient RD process can be used in the pavement.