01082886

Component

http://www.trb.org/Publications/Blurbs/159461.aspx

This study analyzes the physical and performance characteristics of asphalt concrete mixtures with aggregate structures designed using the Bailey method of aggregate gradation evaluation. Three aggregate types—limestone, sandstone, and granite—were considered in this study. Three different aggregate structures of 12.5-mm nominal maximum particle size were designed for each aggregate type. Mixtures were designed for high traffic levels. The binder type selected was performance grade 76-22M. The compaction characteristics of the mixtures were analyzed using data from the Superpave gyratory compactor. Locking points and compaction indices were defined and determined for all the mixtures in the study. Simulative (Hamburg wheel tracking test) and fundamental (semicircular fracture and IT strength) tests were conducted to determine laboratory performance properties and evaluate the mixtures under different loading and environmental conditions. The design number of gyrations (Ndesign) recommended by Superpave was compared to the locking points obtained from this study. The data indicate that the current Ndesign level recommended by Superpave is much higher than the locking points of the mixtures and may subject the mixtures to high compaction energy for an extended period of time. Selected mixtures were designed using the locking point as the design number of gyrations instead of the recommended Superpave Ndesign. The data presented in this paper suggest that mixes with dense aggregate structures can be designed using their locking point instead of the recommended Ndesign. The designed mixtures maintained good resistance to permanent deformation and maintained an adequate level of durability.

01082884

English

pp 12-32

2007-12

Transportation Research Circular

Web

Figures (10) ; Photos (1) ; References (16) ; Tables (2)

Aggregate gradation; Asphalt concrete; Durability; Grain size (Geology); Granite; Laboratory tests; Limestone aggregates; Mix design; Performance measurement; Rutting; Sandstones; Superpave

Bailey method

Highways; Materials; I31: Bituminous Binders and Materials

TRIS, TRB

Dec 20 2007 10:37AM

• Analysis of Oklahoma Mix Designs for the National Center for Asphalt Technology Test Track Using the Bailey Method
• Current Superpave Mix Design Practice: Survey of the User–Producer Regions
• Using the Indirect Tension Test to Evaluate Rut Resistance in Developing Hot-Mix Asphalt Mix Designs
• Using the Superpave Gyratory Compactor to Estimate Rutting Resistance of Hot-Mix Asphalt