00206964

Component

http://onlinepubs.trb.org...rbbulletin/187/187-006.pdf

THE FOLLOWING MAJOR CAUSES OF UNSATISFACTORY CONDITIONS IN FLEXIBLE PAVEMENTS ARE DUSCUSSED: (1) INADEQUATE THICKNESS OF SUBBASE, BASE AND PAVEMENT, (2) INADEQUATE COMPACTION IN THE SUBGRADE, SUBBASE, AND BASE, (3) INADEQUATE DURABILITY IN THE BITUMINOUS LAYERS, AND (4) INADEQUATE STABILITY IN THE BITUMINOUS PAVEMENT UNDER TRAFFIC DURING HOT WEATHER. HOWEVER, WHEN DISTRESS OCCURS IN AN ACTUAL PAVEMENT, BOTH COMPACTION AND SHEAR DEFORMATION ARE USUALLY INVOLVED AND IT IS NECESSARY TO ATTEMPT TO SEPARATE THE TWO. COMPACTION, THOUGH CONTRIBUTING TO UNDESIRABLE SURFACE IRREGULARITY, INCREASES THE STRUCTURAL STRENGTH OF A PAVEMENT AND BECOMES SUCCESSIVELY LESS UNDER A GIVEN INTENSITY OF TRAFFIC. SHEAR DEFORMATION BECOMES SUCCESSIVELY MORE PRONOUNCED IN ITS RESULTANT EFFECTS UNDER A GIVEN INTENSITY OF TRAFFIC AND HAS NO BENEFICIAL EFFECTS. IT IS CONCLUDED THAT IT IS IMPORTANT TO RECOGNIZE THE OCCURRENCE OF SHEAR DEFORMATION AS A PRIMARY MECHANISM OF FAILURE REGARDLESS OF THE POINT AT WHICH RESULTANT SURFACE IRREGULARITIES BECOME INTOLERABLE FOR THE USE FOR WHICH THE PAVEMENT WAS DESIGNED. IF THE BEHAVIOR IS TO BE USED TO IMPROVE THE DESIGN CRITERIA, IT IS NECESSARY TO ESTABLISH THE LAYER OR LAYERS WHICH HAVE BEEN OVERSTRESSED. THIS DEFORMATION REQUIRES CAREFUL OBSERVATION AND SAMPLING AND TESTING.

No 187, pp 72-75, 3 FIG 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.

01499746

4p

1958

Highway Research Board Bulletin

Digital/other

Base course (Pavements); Bituminous pavements; Compaction; Defects; Deformation; Design; Durability; Failure; Flexible pavements; Pavement distress; Pavement performance; Pavements; Shear strength; Stability (Mechanics); Subbase (Pavements); Subgrade (Pavements); Thickness

Criteria; Design criteria; Subbase

Design; Highways; Pavements

TRIS, TRB

Oct 7 1994 12:00AM

• CONSIDERATION OF APPROPRIATE ELEMENTS FOR RATING A PAVEMENT
• EVALUATION OF PERFORMANCE OF AN EXISTING CONCRETE PAVEMENT UNDER ACCELERATED LOAD APPLICATION
• Evaluation of Rigid Pavement Performance
• PAVEMENT PERFORMANCE INVENTORY IN MICHIGAN
• TYPES AND CAUSES OF FAILURE IN HIGHWAY PAVEMENTS
• WARNING SIGNS OF PAVEMENT DISTRESS