Classification of Reclaimed Asphalt Pavement (RAP) material using simple indicative tests: Fid-Bau Portal

Classification of Reclaimed Asphalt Pavement (RAP) material using simple indicative tests

Guduru, Gurunath / Kuna, Kranthi K

Highlights • Fragmentation and cohesion tests can be adopted to characterize and classify RAP. • Classification limits were proposed based on fragmentation test indices. • The categories indicate different ranges of Degree of Bitumen Activity in RAP.

Abstract The present study proposes an approach to characterize and classify the Reclaimed Asphalt Pavement (RAP) material based on indicative tests that are repeatable and simple to perform. The aim is to waive the need to extract and/or recover the bitumen from the RAP while characterizing it for the design of hot recycled asphalt mixes. The existing methods to extract and recover bitumen are laborious, expensive, and prone to erroneous results. The objective of the study is achieved by investigating eleven (11 nos.) RAP sources of varying characteristics that are obtained by milling distressed bituminous pavements. Two tests, namely, fragmentation test and cohesion test for which RILEM recommended protocols are available, have been considered to evaluate their potential to characterize the RAP material. From the detailed analysis of experimental results, it was found that the RAP can be effectively characterized based on the indices derived from these two tests, i.e., Sfrag from fragmentation test and Sair-voids from the cohesion test. Hierarchical Clustering on Principal Components (HCPC) analysis on the initial variable dataset suggested that all eleven RAP sources can be clustered into three distinguishable categories based on which the Sfrag classification limits were proposed. The recommended classification approach was verified using three additional RAP sources and four laboratory-produced RAP sources that were not part of the original investigation.