00625543

Component

http://onlinepubs.trb.org...trr/1992/1355/1355-005.pdf

https://scholar.google.co...ANEN&publication_year=1992

Falling weight deflectometers (FWDs) apply a load to the pavement surface that is generated by dropping a mass onto a hit bracket. The resulting impact generates the force that is transmitted to the pavement through a contact plate. A spring set between the falling mass and the hit bracket buffers the impact by decelerating the mass. The greater the deceleration, the greater the force generated. The amount of force generated is a function of the stiffness of the spring set, the amount of mass, and its velocity when it strikes the spring set, plus any dampening that may be part of the system. The Dynatest Model 8000E FWD is used for monitoring pavement sections in the Strategic Highway Research Program (SHRP) Long-Term Pavement Performance (LTPP) study. During the course of the study, several buffer changes were made. To evaluate the effects the buffers have on the loads and deflections, tests were conducted using each buffer set on three pavement structures near the SHRP North Central Regional Office. THe results show the various buffer shapes had an effect on the test results. The differences observed are not considered significant for routine production testing but are expected to be relevant in research work involving viscoelastic materials (asphalt) and dynamic deflection analysis.

This paper appears in Transportation Research Record No. 1355, Nondestructive Structural Evaluation of 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

01405034

English

Lenngren, Carl

p. 37-51

1992

Transportation Research Record

030905219X

Figures (7) ; References (6) ; Tables (3)

Asphalt pavements; Deflection; Falling weight deflectometers; Loads; Pavement performance; Testing

Long-Term Pavement Performance Program; Strategic Highway Research Program

Design; Highways; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces

TRIS, TRB

Dec 16 1993 12:00AM

• ALTERNATIVE METHOD FOR TEMPERATURE CORRECTION OF BACKCALCULATED EQUIVALENT PAVEMENT MODULI
• COMPREHENSIVE EVALUATION OF FIVE SENSORS USED TO MEASURE PAVEMENT DEFLECTION
• EFFECT OF DEPTH TO BEDROCK ON DEFLECTION BASINS OBTAINED WITH DYNAFLECT AND FALLING WEIGHT DEFLECTOMETER TESTS
• ESTIMATING DAMAGE EFFECTS OF DUAL VERSUS WIDE BASE TIRES WITH MULTIDEPTH DEFLECTOMETERS
• EVALUATION OF A DUAL-LOAD NONDESTRUCTIVE TESTING SYSTEM TO BETTER DISCRIMINATE NEAR-SURFACE LAYER MODULI
• FIELD AND LABORATORY DETERMINATION OF ELASTIC PROPERTIES OF PORTLAND CEMENT CONCRETE USING SEISMIC TECHNIQUES
• MODELING OF GROUND-PENETRATING RADAR WAVE PROPAGATION IN PAVEMENT SYSTEMS
• NONLINEAR EFFECTS IN FALLING WEIGHT DEFLECTOMETER TESTS
• RADAR PAVEMENT THICKNESS EVALUATIONS FOR VARYING BASE CONDITIONS
• SIMPLIFIED, RATIONAL APPROACH TO FALLING WEIGHT DEFLECTOMETER DATA INTERPRETATION
• VARIABILITY IN ESTIMATION OF STRUCTURAL CAPACITY OF EXISTING PAVEMENTS FROM FALLING WEIGHT DEFLECTOMETER DATA