Rock Pockets...

Rock pockets and other anomalies in a concrete pavement can be determined by skillful use of geophysical methods.  Rock pockets occur when aggregate collects without a proper amount of binding cement.  This may happen in placement or vibration of the concrete.  The presence of rock pockets weakens the concrete structure.  Rock pockets can be found with high frequency GPR and Impact Echo.

Techniques Recommended

Surface NDT Methods:

• Ground penetrating radar (GPR).
• Impact Echo.

While other methods are available or under development, the ones listed above provide cost-effective determination of pavement thickness.