Measuring pavement response – Design, development and application of sensors and data evaluation for test and in-service pavements

Resumen

The main task of pavement engineers is the design and construction of
pavement structures being able to resist traffic loads and climatic impacts over the design
operating life. Pavement design is mostly based on empirical or mechanistic-empirical
models. Monitoring pavement response and performance over a long period of time is
essential for establishing these methods. Furthermore, mechanistic-empirical or analytical
models need adequate material parameters as input. Material parameters are usually
determined in dynamic laboratory tests, which in nature depend on the boundary conditions of
the specific test method. Thus, these parameters are often more test-specific parameters rather
than material parameters and often boundary test conditions are not consistent with in-situ
conditions.
Accelerated testing and response measurements on instrumented full-scale pavements are
suitable methods to bridge the gap between performance monitoring of pavement structures,
laboratory testing and analytical methods. Usually they are the only means to validate
theoretical models by measuring the mechanical response induced by traffic and climatic
impact. Though a large number of tests on instrumented full-scale pavements have been
conducted worldwide, the appropriate measurement of stresses, strains and deformations in
pavement structures still remains a difficult task. Despite of the difficulties response
measurements can provide important information to validate analytical models or to define
adequate boundary conditions for dynamic laboratory tests of pavement materials.
This paper gives a short overview over the basic principles of pavement instrumentation
and sensor design and shows examples and evaluations of selected response measurements to
heavy vehicle and FWD loading at the full scale pavement test facility at the Federal Highway
Research Institute BASt in Germany. Focus is on the evaluation of redundant sensor
arrangement and statistical evaluation regarding the variations and scatter. Finally, an outlook
is given on an improved sensor design and improved data acquisition techniques for longterm
response measurements on in-service pavements.