Estimating Optimum Compaction Level for Dense-Graded Hot-Mix Asphalt Mixtures

Khalid Al Shamsi, Louay N. Mohammad

Abstract


 A critical step in the design of asphalt mixtures is laboratory compaction. Laboratory compaction should reflect field compaction and should produce mixtures that are economical and possess high structural stability. During the compaction process, asphalt mixtures are subjected to certain amount of compaction energy in order to achieve the required density. The Superpave volumetric mix design is based on compacting HMA mixtures to a specified compaction level described by the number of gyrations from the Superpave gyratory compactor (SGC). This level is termed Ndes and represents the required energy (based on the traffic level expected) to densify the mixture to a 4% air voids level. This paper re-examines the Superpave compaction requirements through extensive laboratory investigation of the response of a number of asphalt mixtures to the applied compaction energy. It also presents an alternative method to estimate the number of gyrations at which a mixture first reaches an optimum aggregate interlock and hence prevents overcompaction problems that might result in unstable aggregate structures or dry asphalt mixtures. A total of 12 HMA mixtures were studied. During compaction, force measurement was made using the pressure distribution analyzer (PDA). The compaction characteristics of the mixtures were analyzed using data from the PDA and the traditional Superpave Gyratory Compactor (SGC) results.

 


Keywords


Locking point, Mix design, Asphalt mixtures, Pavement materials, Laboratory compaction

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References


Alabama Department of Transportation, 2002, "Special Provision No. 02-0360(5)-2004 - Amendment for Section 424 ," Alabama Standard Specifications.

American Association of State Highways and Transportation Officials, 2004," Bulk Density (Unit Weight) and Voids in Aggregate". AASHTO Designation T 19.

Angelo, D.J., Harman, T.P. and Paugh, C.W., 2001, "Evaluation of Volumetric Properties and Gyratory Compaction Slope for the Quality Control of Hot Mix Asphalt Production," Asphalt Paving Technology: Association of Asphalt Paving Technologists- Proceedings of the Technical Sessions, Vol. 70, pp. 729-761.

Asphalt Institute, 2001. "Superpave Mix Design," Superpave Series No. 2, Asphalt Institute, Lexington, KY.

Cominsky R J., Leahy R B. and Harrigan E T., 1994, "Level One Mix Design: Materials Selection,

Compaction, and Conditioning," Strategic Highway Research Program, SHRP-A-408.

Georgia Department of Transportation, 2003, "Special Provision-Section 828-Hot Mix Asphaltic Concrete Mixtures,".

Guler, M., Bahia,H.U., Bosscher, P, J. and Plesha, M. E., 2000, "Device for Measuring Shear Resistance of Hot-Mix Asphalt in Gyratory Compactor," Transportation Research Record No. 1723, Transportation Research Board, Washington, DC.

SAS Institute Inc, 2002-2003, "SAS Help and Documentation". Cary, NC, USA. The Online Magazine of the Asphalt Institute, 2007, " www.asphaltmagazine.com".

Vavrik, W. R. and Carpenter, S.H., 1998, "Calculating Air Voids at Specified Number of Gyrations in Superpave Gyratory Compactor," Transportation Research Record 1630, Transportation Research Board, Washington, DC, pp. 117-125.




DOI: http://dx.doi.org/10.24200/tjer.vol7iss1pp11-21

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Copyright (c) 2017 Khalid Al Shamsi, Louay N. Mohammad

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