Use of FWD, GPR and IP in Combination on Complex Pavement Projects – Including Case Studies

The pavement structure may include variable materials (type, thickness and condition).
Conventional borehole investigation and pavement inspection may not be enough for more
complex cases.

The FWD/GPR/IP data combined with the results of borehole investigation, laboratory testing and
pavement inspection provides powerful information about the existing pavement. It allows to
explain the behaviour of the pavement and then to determine the necessary design. Often the
pavement structures are placed on variable soils that undergo seasonal variation in moisture
conditions. The evaluation of pavement condition and designing the most effective and at the
same time reliable pavement rehabilitation can be a challenge. The conventional borehole
investigation and pavement conditions visual inspection provide very important information but
this may not be enough for more complex cases, particularly for pavement carrying heavy,
variable traffic.

Falling Weight Deflectometer (FWD), Ground Penetrating Radar (GPR) and pavement profilers
have been used in pavement engineering for some time. This paper will describe the use of FWD,
GPR and inertial or other types of profilers in combination on complex pavement projects. On
some projects Grip Tester was also added to measure the frictional characteristics of the
pavement.

The authors of this paper have been doing pavement condition investigation and rehabilitation for
years and on large number of projects and have concluded that on complex projects combing the
data from all three devices and conventional investigation is critical to put the puzzle together. It
allows to explain the behaviour of the pavement and then to design the optimum solution. This
paper includes real life examples of the investigations on municipal and airport projects.