ISSN: 0090-3973
Page Count: 8

Quantifying the Confidence Levels of Deformation Measurements in Asphalt Concrete

Levenberg, E
Ph.D Student,Civil and Environmental Engineering, Technion,

Uzan, J
Professor of Civil Engineering,Civil and Environmental Engineering, Technion,

(Received 25 November 2002; accepted 10 March 2004)

Abstract

An experimental approach for measuring surface strains in asphalt concrete (AC) samples is presented in this paper. It is equivalent to the local attachment of a large number of linear variable displacement transducers (LVDTs) with gage lengths ranging from 5 to 80 mm. The strain distribution properties developed under conditions of uniaxial tension are studied and analyzed for one AC mixture. It is shown that gage lengths of the order of the nominal maximum aggregate size measure a wide range of strain values: from zero strain up to 5 times the average strain. Moreover, as the gage length is increased, the scatter is reduced and the individual measurements yield values that are closer to their average. Subsequently, the confidence levels associated with using a limited number of gages with a given gage length are quantified. The results are then used to assess test protocol recommendations related to AC sample instrumentation. The size scale of the material's Representative Volume Element (RVE) is also addressed.

Keywords:
local strain, asphalt concrete, gage length, representative volume element

Paper ID: JTE11804
DOI: 10.1520/JTE11804
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