Investigation of the Black Rock Issue for Recycled Asphalt Mixtures


As part of the NCHRP 9-12 research, Incorporation of Reclaimed Asphalt Pavement in the Superpave system, a study was carried out to investigate whether Reclaimed Asphalt Pavement (RAP) acts like a black rock when added to hot mix asphalt mixtures. Three RAPS with different stiffness, two new binders, and two RAP ratios were used. For mixtures with 10% RAP, there was no significant difference between the three mixture cases but for 40% RAP ratio, the standard practice mixtures were closer to the total blending than the black rock. Statistical analysis verified this observation for most studied cases. Only 18.8% of studied cases proposed that RAP is a black rock but 50% of studied cases showed that there was no difference between the cases at low RAP content. This was in agreement with the Expert Task Group suggestion that 10% RAP will not significantly affect the asphalt mixture containing RAP.

Meeting Name

2000 Annual Meeting of the Association of Asphalt Paving Technologists (2000: Mar. 13-15, Reno, NV)


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Asphalt Mixture; Black Rock; Blending Chart; Recycling; Superpave

International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2000 Association of Asphalt Paving Technologists (AAPT), All rights reserved.

Publication Date

01 Mar 2000

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