Road

Case Study

The right-of-way image of section 7, station 500 feet shows a cracked and sealed AC pavement with a stretch of about 5 feet where the shoulder was broken away under the fog line. The profile and signal strength for the five scans taken nominally at the positions shown by the transverse red lines has been plotted.

Analysis

Scan 7059 In addition to the long sealed longitudinal crack (blue arrow), a transverse sealed crack is visible in the normalized signal strength curve as a downward spike. Crossfall slope discontinuity present at the longitudinal crack.The fog line results in a clear plateau suitable for locating to profile transversely.

Scan 7064 Shoulder/EOP is (7059 also)is gently rounded. Crack at EOP is visible in profile.

Scan 7083 Chunk of broken shoulder presents a blip in profile in the gravel.

Scan 7115 The abrupt drop off of the broken shoulder is noticeably different (also in 7083 and 7130)from the normal rounded shoulder in 7059 and 7065. The reduced signal from three sealed cracks is apparent.

Scan 7130 A pit which would hold a puddle of water from rain is shadowed in the image but clear in the profile. The outcome of repainting the fogline after the shoulder failed is uniform fogline intensity plateaus in all the scans, even where the profile reveals missing shoulder under the fog line.