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Title:

MOISTURE DAMAGE CUTOFF RATIO SPECIFICATIONS FOR ASPHALT CONCRETE

Accession Number:

00602686

Record Type:

Component

Availability:

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Order URL: http://worldcat.org/isbn/0309050502

Abstract:

Moisture susceptibility of asphalt concrete (AC) mixtures is identified by performing laboratory tests on dry- and wet-accelerated conditioned specimens. Excessive moisture susceptibility is associated with low ratios of wet-to-dry mechanical properties. Highway agencies use values of cutoff wet-to-dry ratios for resilient modulus and for indirect tensile strength as specifications. Mixtures having wet-to-dry ratios lower than the cutoff ratios have excessive moisture susceptibility and require treatment before paving. Currently, most highway agencies apply either a resilient modulus cutoff ratio of 0.70 or an indirect tensile strength cutoff ratio of 0.75. The University of Idaho AC moisture damage analysis system (ACMODAS) programs on field performance are applied to predict cutoff ratios, compare predicted cutoff ratios to currently used ratios, classify AC mixture moisture susceptibility, and recommend cutoff ratios to be used in practice. Two cutoff ratios are necessary to control moisture susceptibility both for fatigue cracking and for wheelpath rutting field distresses. These cutoff ratios are 0.80 for resilient modulus and 0.85 for indirect tensile strength, and both should be applied simultaneously. (Simultaneous application of the (lower) currently used cutoff ratios may only control fatigue cracking.) Applying individual cutoff ratio values to each material, about 25% of mixtures, which cannot be treated by conventional additives or other means to obtain desired fatigue cracking performance because of water-induced brittleness, have cutoff ratios greater than 1. However, the other mixtures can be treated, if need be, to obtain desired performance; their cutoff ratios are less than 1. Identification of these mixtures is discussed.

Supplemental Notes:

This paper appears in Transportation Research Record No. 1269, Asphalt Mix Materials and Mixtures 1990. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved

Monograph Accession #:

01407214

Authors:

Lottman, Robert P
Brejc, Stephen

Pagination:

p. 87-91

Publication Date:

1990

Serial:

Transportation Research Record

Issue Number: 1269
Publisher: Transportation Research Board
ISSN: 0361-1981

ISBN:

0309050502

Features:

Figures (1) ; References (5) ; Tables (1)

Old TRIS Terms:

Subject Areas:

Highways; Materials; I31: Bituminous Binders and Materials

Files:

TRIS, TRB, ATRI

Created Date:

Dec 31 1990 12:00AM

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