Technical information

3-2
air-conditioning unit. In its maximum capacity, the air temperature inside the test area
can be reduced relative to warmer outdoor conditions to 60ºF (15.5ºC). In this study the
temperature in the testing area was set to 60ºF (15.5ºC). A humidity detector is
positioned close to the test pit; in principle, it is possible to increase the humidity in the
test area by intentionally ponding water.
Figure 3.1.1: Schematic floor plan of INDOT APT facility.
The APT loading system is mounted on a large steel frame with beams spanning
across and bridging the test pit. The frame itself is fixed on each side to steel rails
embedded in the concrete floor. The fixture can be loosened to allow positioning of the
frame above any test-lane of choice. The loading system is designed to produce a
downward force of up to 20,000 lb (9,080 kg). This force is produced by four