01005169

Component

https://doi.org/10.3141/1905-08

http://scholar.google.com...hter&publication_year=2005

In 1988 the Strategic Highway Research Program purchased four falling weight deflectometers (FWDs). During the acceptance testing it became evident that an improved procedure for calibration was needed to determine whether the specifications for the precision and the accuracy of the sensors were achieved. The authors were responsible for developing the procedure. This paper reports on the steps taken during the development of the calibration protocol. The reasons underlying the equipment and the procedures chosen are discussed. The sources of error in FWD measurements are identified, and ways that have been used to reduce those errors are reported. The goal was to reduce the systematic (bias) error to less than 0.3% through calibration. This level of error ensures that the random measurement error is larger than the systematic error for all pavement deflections less than 600 µm [24 mils (1 mil = 0.001 in.)]. Experience has shown that most highway pavements deflect less than 600 µm. The effects of FWD measurement errors on backcalculated pavement moduli are briefly reviewed. Verification of the protocol by several means showed that the calibration goal was achieved. Subsequent experience with the calibration protocol has shown that it has been effective and that it ensures high quality in the FWD data.

01005160

English

pp 67-72

2005

Transportation Research Record: Journal of the Transportation Research Board

0309093775

Print

Figures (1) ; Photos (6) ; References (6)

Accuracy; Calibration; Data quality; Errors; Falling weight deflectometers; Precision; Sensors; Specifications

Strategic Highway Research Program

Test protocols

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

TRIS, TRB, ATRI

Oct 3 2005 2:06PM

• Accelerated Pavement Rehabilitation and Reconstruction with Long-Life Asphalt Concrete on High-Traffic Urban Highways
• Application of Reliability Concept in Concrete Pavement Rehabilitation Decision Making
• Asphalt Pavement Rehabilitation Treatment: Analysis of 20 Years of Performance
• Assessment of Pavement Layer Condition with Use of Multiload-Level Falling Weight Deflectometer Deflections
• Falling Weight Deflectometer Correlation
• Fast Nondestructive Field Test Method to Determine Stiffness of Subsurface Layer in Thin Surface Hot-Mix Asphalt Pavement
• Full-Car Roughness Index as Summary Roughness Statistic
• Identifying Friction Variations with the Standard Smooth Tire for Network Pavement Inventory Friction Testing
• Implementation of Cold In-Place Recycling with Expanded Asphalt Technology in Canada
• Implementation of Reliability-Based Backcalculation Analysis
• Interpretation of Transverse Profiles to Determine the Source of Rutting Within an Asphalt Pavement System
• Methodology for Detection of Defect Locations in Pavement Profile
• Modeling Hydroplaning and Effects of Pavement Microtexture
• Monitoring Pavement Changes in a Rehabilitation Project with Continuous Rolling Dynamic Deflectometer Profiles
• Seed Modulus Generation Algorithm for Backcalculation of Flexible Pavement Moduli
• Simple Model for Pavement Damage
• Wisconsin Experiences with Reflective Crack Relief Projects