Identification and Assessment of the Dominant Aggregate Size Range (DASR) of Asphalt Mixture
2006 (English)In: Journal of Asphalt Paving Technologists, ISSN 0270-2932, Vol. 75, 789-814 p.Article in journal (Refereed) Published
Coarse aggregate structure or interlock is critical for resistance to rutting, and recent work has shown that it can also play a significant role in resistance to damage and fracture. Therefore, large enough aggregates should engage dominantly in the structure for good mixture performance. This study focused on the development of a conceptual and theoretical approach to evaluate coarse aggregate structure based on gradation.In soil mechanics, it has been well established that the porosity of granular materials in the loose state is approximately constant between 45% and 50%, regardless of size or gradation. This implies that one can use porosity as a criterion to assure contact between large enough particles within the mixture to provide suitable resistance to deformation and fracture. Calculations performed for gradations associated with typical dense graded mixtures indicated that the porosity of particles retained on any single sieve was significantly greater than 50%, even for gradations associated with the maximum density line. Since many dense graded mixtures are known to provide suitable resistance to deformation and fracture, then there must be a range of contiguous coarse aggregate particle sizes that form a network of interactive particles with a porosity of less than 50%.A theoretical analysis procedure was developed to calculate the center to center spacing between specific size particles within a compacted assemblage of particles of known gradation. Calculations performed with this procedure indicated that the relative proportion of two contiguous size particles, as defined by the standard arrangement of Superpave sieves, can be no greater than 70/30 in order to form an interactive network. Thus, the 70/30 proportion can be used to determine whether particles on contiguous Superpave sieves can form an interactive network of particles in continuous contact with each other. The range of particle sizes determined to be interactive was referred to as the dominant aggregate size range (DASR) and its porosity must be no more than 50% for the particles to be in contact with each other.It was concluded that porosity of the DASR may provide a good criterion for determining the suitability of gradation for dense-graded asphalt mixture.
Place, publisher, year, edition, pages
ASSOCIATION ASPHALT PAVING TECHNOLOGISTS , 2006. Vol. 75, 789-814 p.
gradation, dominant aggregate, porosity, spacing, interstitial, interaction
IdentifiersURN: urn:nbn:se:kth:diva-84000ISI: 000243589000022OAI: oai:DiVA.org:kth-84000DiVA: diva2:499068
TSC import 1683 2012-02-10. QC 201202292012-02-132012-02-132013-03-20Bibliographically approved