A sampling-type crack survey was made in July 1969; 200 feet in each 1000 feet were sampled. The average interval between cracks was 5.78 feet. Paving was completed in late 1968. The average crack interval in July 1970 was 4.14 feet. The 1970 survey was also a sampling type.

It is apparent that cracking approached maturity or equilibrium during the first year. Apparently, too, most of the cracking occurred during the first few weeks after construction – which suggests curing shrinkage as a contributory cause. A discussion of the significance of time and temperature will follow the presentation of other survey observations.

A frequency-distribution graph of crack intervals was prepared (Figure 1) to illustrate the mode. Although no discrete mode is apparent, it is evident that there was a strong tendency for cracks to occur at intervals ranging between 1 and 6 feet. The dominant interval appears to be 2 feet. Typical cracks are illustrated in the accompanying photographs (Figures 2 through 6).

Report Date


Report Number

No. 300

Digital Object Identifier



Memo from James H. Havens (Department of Transportation, Commonwealth of Kentucky) to William B. Blake (Department of Transportation, Commonwealth of Kentucky), December 8, 1970.