Book Description

In the fall of 1984, the Kansas Department of Transportation constructed a project involving cracking, seating, and overlaying a portland cement concrete pavement. The project is located in Wyandotte County on K-7 highway, north of K-32. This project is on the west side of the Kansas City metropolitan area. Eight experimental sections and one control section were stipulated for this project. One section of regular construction was selected for the control section. Four of the eight test sections were designated to be cracked at 0.9 m (3 ft) centers, and the other four were cracked at 1.5 m (5 ft) centers. One half of each spacing pattern was saw cut at the quarter points of the 18.7 m (61.5 ft) panels [approximately 4.6 m (15 ft) spacing, minimum 127 mm (5 in.) deep, maximum 13 mm (0.5 in.) wide] prior to cracking. Four sections had minimal joint repair; four had normal joint patching. There have been no easy determinants as to why the transverse cracking is low in some sections, and high in others. In some years it appears to be one factor, but the next year the factor has appeared to change. After 10 years there is no difference attributable to the cracking spacing, probably because both spacings are too large to adequately distribute the thermal movements. Slightly better performance was noted in sections that have minimal joint patching. More recent projects have used rubblizing as a rehabilitation technique. These have not shown significantly better performance than the cracking method. More investigation needs to be done to quantify the effect of various components that are used in this technique.