PHOTOGRAPHY OF FLEXIBLE AIRFIELD PAVEMENTS BY MEANS OF THE SUR/FAX METHOD OF STRIP PHOTOGRAPHY.

The SurFax system was adapted to airfield runway photography. A map was made showing all of the planimetric surface defects. Although the size of the cracks detected depends somewhat on the contrast between the crack and the surrounding pavement, cracks of oneeighth of an inch or larger can be detected under practically all conditions. It was established that the line-oflight gives qualitative data concerning the rutting across the direction of travel of the vehicle. Where the pavement is extremely smooth, ruts of one quarter of an inch deep in eight feet can be detected. Where the pavement is rough, the line-of-light is less sharp, making it harder to measure the deviation from the straight line. This sharpness or lack of it provides an indication of the condition of the pavement surface.