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http://onlinepubs.trb.org...s/trr/1984/954/954-006.pdf

https://scholar.google.co...orge&publication_year=1984

The principal objective of this research was to study the influence of the environment on thee thickness of flexible pavements. Environmental variables considered include general soil conditions and temperature effects. As identified in previous studies, six climatic zones were recognized. Weather information and soil properties were collected for 175 typical stations covering the continental United States, excluding Alaska. Based on the criteria of rutting of 1.25 cm (0.5 in.) and thermal cracking of 115 m/1000 sq. in. (35 ft/1,000 sq. ft.), appropriate asphalt-cement grades were selected for each station. To consider the interaction of temperature and modulus with fatigue damage, the concept of effective modulus was introduced. The effective modulus calculated by using the appropriate asphalt grade was found to be nearly constant within a zone but varied considerably from on zone to another. A sensitivity analysis was performed on the AASHO flexible pavement design equation, the purpose of which was to determine the effect of the regional factor and the soil support value on the structural number. After these two items had been combined with the change in the layer coefficient due to modulus change, their overall effect on pavement thickness was evaluated. The ratio of the thickness required at a given station to that required at reference conditions (namely, asphalt effective modulus of 34.5 kPa (5 x 10 to the 5th power psi), regional factor of 1.0, and soil support value of 5.0) is defined as the depth factor. The depth factor ranged from as low as 0.45 in Florida, parts of Mississippi, Alabama, Georgia, and the Carolinas to as high as 1.60 in regions of Montana, North Dakota, and South Dakota. The higher the depth factor, the more severe the influence of environment on pavement performance. Examples to illustrate how the depth factor may be incorporated into the AASHO flexible design are given.

Publication of this paper sponsored by Committee on Flexible Pavements. 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

01419839

pp 52-58

1984

Transportation Research Record

0309036747

Print

Figures (6) ; Maps (4) ; References (8) ; Tables (7)

Asphalt cement; Climate; Cracking; Environmental impacts; Fatigue (Physiological condition); Flexible pavements; Modulus; Pavement design; Pavement performance; Pavements; Ruts (Pavements); Sensitivity analysis; Soils; Temperature; Thermal stresses; Thickness; Weather

Pavement thickness; Rut; Soil conditions

Environment; Geotechnology; Highways; Pavements; I23: Properties of Road Surfaces

TRIS, TRB

Dec 30 1984 12:00AM

• EFFECT OF CONCRETE SHOULDERS ON CONCRETE PAVEMENT PERFORMANCE
• EFFECT OF FROZEN SUPPORT AND TRIDEM AXLES ON CONCRETE PAVEMENT PERFORMANCE
• FINITE-ELEMENT MODEL WITH STRESS-DEPENDENT SUPPORT
• K SUB R: THE RESILIENT MODULUS OF SUBGRADE REACTION
• PERFORMANCE OF CRUSHED-STONE BASE COURSES
• SEASONAL EFFECTS ON THE STRENGTH OF PAVEMENT STRUCTURES
• SEASONAL LOAD LIMIT DETERMINED BY THE CRITERION OF UNIFORM FAILURE RATE
• STRESSES IN FULL-DEPTH GRANULAR PAVEMENTS
• STRUCTURAL COMPARISON OF TWO COLD RECYCLED PAVEMENT LAYERS
• STRUCTURAL MODEL FOR CONCRETE BLOCK PAVEMENT
• USE OF SURFACE DEFLECTION FOR PAVEMENT DESIGN AND EVALUATION