The Multi-Depth Deflectometer: A Multistage Sensor for the Measurement of Resilient Deflections and Permanent Deformation at Various Depths in Road Pavements

摘要

In order to understand the behavior of different pavements a knowledge of the variation of deflection with depth under the action of traffic is needed. The Multi Depth Deflectometer (MDD) was developed to meet this need and this report describes its development and construction. The preparation of a site to accommodate this instrument is important to ensure reliability. The instrument is left on the pavement throughout the period of testing which in the case of an accelerated evaluation can be for a few months. The expected accuracy was estimated both in the laboratory and in the field and it is concluded that it is acceptable for pavement design purposes.