00468681

Component

http://onlinepubs.trb.org...trr/1987/1121/1121-001.pdf

https://scholar.google.co...Ruth&publication_year=1987

Methods to supplement conventional elastic layer analysis of nondestructive test (NDT) measurements are needed to improve the ability to evaluate layer moduli. In particular, the determination of asphalt concrete moduli (E sub 1) for thin pavements often results in substantial errors in the values of E sub 1 and E sub 2 using iteration techniques in computer programs (e.g., ELSYM-5, ISSEM-4). The development and predictive reliability of two methods of E sub 1 determinations are presented for the purpose of improving the analysis techniques used in pavement evaluation studies. The methods are classified as direct and indirect even though both methods are based on E sub 1-values from dynamic indirect tension testing of asphalt concrete specimens (cores or compacted samples). The direct method requires the development of an E sub 1-temperature relationship using E sub 1-values from the indirect tension test, which is conducted at different temperatures. The indirect method is based on a previously developed relationship between E sub 1 and constant power viscosity of the asphalt as obtained from Schweyer constant stress rheometer tests. Cores or cut samples from the pavement are separated into individual layers and the asphalt is recovered using reflux and Abson methods. Asphalt viscosity determinations from tests at different temperatures are used in a regression analysis to develop an asphalt viscosity versus temperature (deg K) relationship. Pavement temperature recorded at the time of NDT measurements is used to determine a corresponding asphalt viscosity from the relationship. E sub 1 is then predicted from the developed equations using this asphalt viscosity-value. The reliability of the E sub 1 predictions is appraised by comparing layer moduli from BISAR simulation of Dynaflect-measured deflection basins and ISSEM-4 predictions of falling weight deflectometer deflection basins. Comments are made on the effects of air void content and mix characteristics.

Publication of this paper sponsored by Committee on Strength and Deformation Characteristics of Pavement Sections. 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

01418084

pp 1-6

1987

Transportation Research Record

66th Annual Meeting of the Transportation Board

0309045010

Print

Figures (4) ; References (10) ; Tables (1)

Air voids; Asphalt concrete; Computer programs; Deflection; Dynaflect; Estimating; Falling weight deflectometers; Forecasting; Mix design; Modulus; Pavement layers; Regression analysis; Reliability; Temperature; Tension; Viscosity

Data and Information Technology; Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways

TRIS, TRB, ATRI

May 31 1988 12:00AM

• AN EVALUATION OF DESIGN HIGH-WATER CLEARANCES FOR PAVEMENTS
• AN EXAMINATION OF ENVIRONMENTAL VERSUS LOAD EFFECTS ON PAVEMENTS
• CHARACTERIZING TEMPERATURE EFFECTS FOR PAVEMENT ANALYSIS AND DESIGN
• ECONOMIC IMPACT OF PAVEMENT SUBSURFACE DRAINAGE
• EFFECT OF MOISTURE ON THE STRUCTURAL PERFORMANCE OF A CRUSHED-LIMESTONE ROAD BASE
• EFFECT OF RAINFALL ON THE PERFORMANCE OF CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS IN TEXAS
• MOISTURE IN PORTLAND CEMENT CONCRETE
• STRESS CAUSED BY TEMPERATURE GRADIENT IN PORTLAND CEMENT CONCRETE PAVEMENTS
• TEMPERATURE RESPONSE OF CONCRETE PAVEMENTS
• USE OF OPEN-GRADED, FREE-DRAINING LAYERS IN PAVEMENT SYSTEMS: A NATIONAL SYNTHESIS REPORT