The overall purpose of the instrumentation program is to measure the structural performance of the concrete and reinforcing bars (a) during and directly after construction of the test pavement, and (b) under test loading. The typical instrumentation layout is shown in this figure for one lane, and consists of steel strain gages, static and dynamic strain gages, and thermocouples. No sensors were installed in the splice zone.

Data collected directly after construction included the temperature profile in the slab, concrete shrinkage and thermal contraction, the bond-slip relationship between the steel and concrete, and stress development within the reinforcing bars. Data to be collected during dynamic testing will be used to evaluate the progressive performance and failure of the sections. Shown here is an induced crack at one of the Soff-Cut locations.

Strain gages were installed at three levels within the concrete – two below and one above the reinforcing steel – to measure the strain in the concrete during curing. The strain is ultimately one of the causes of cracking in the concrete. The reinforcing bars will hold these cracks tightly together. Strain gages were also installed on the reinforcing bars to measure the tension in the reinforcing steel during test loading.

Dynamic strain gages measure the stress in the concrete during test loading.

Over 250 separate sensors were installed. Their wiring exits each pavement lane at a single location.

All sensors are wired to a Campbell Scientific data logger that automatically reads the instruments on a pre-specified time schedule.

Pertinent climatic information such as air temperature, wind speed, cloud cover, and solar radiation is collected by an on-site weather station.