Field Evaluation of Asphalt Film Thickness as a Design Parameter in Superpave Mix Design


Research shows that asphalt film thickness (AFT) is related to mix performance. The use of AFT as a mix design parameter has always been a challenge because of the complexity of estimating AFT based on mix parameters. The aggregate surface area and the effective volume of asphalt are important components in the calculation of AFT. This study compares the voids in mineral aggregate (VMA) and AFT as mix design parameters against the field performance of Superpave mixes. Film thickness was estimated by different formulas using calculated aggregate surface area. Data on early flushing sections of Superpave mixes was used to correlate film thickness to distress development and other mix design parameters. The pavement sections considered for the study were observed to have undergone flushing and rutting problems. Field cores from flushed and non-flushed sections were obtained and verified for compliance with Superpave specifications. The results of this research related AFT to mix design parameters but showed that depending on the method of calculation, AFT, as a mix design parameter, may or may not be helpful in explaining specific field performance distresses such as rutting or bleeding.


Civil, Architectural and Environmental Engineering

Keywords and Phrases

Asphalt Film Thickness; Superpave Mix Design; VMA

Document Type

Article - Journal

Document Version


File Type





© 2009 Chinese Society of Pavement Engineering., All rights reserved.

Publication Date

01 Jan 2009

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