High Performance Concrete Pavements
CHAPTER 18. KANSAS 2 (Hutchinson)
The Kansas Department of Transportation, a national leader on pavement smoothness, has undertaken a project to build a PCC pavement that is "super smooth" and maintains that smoothness for an extended time. This project consists of five special sections, is located in Hutchinson, Kansas, and has a construction start date of April 2001. The project is multifaceted. The initial smoothness will be monitored and controlled with new equipment innovations, while the post-construction smoothness will be evaluated for different construction conditions (weather), mixture properties (w/c ratio), and joint spacings.
To build a super-smooth pavement that maintains most of its original smoothness through increased initial smoothness levels as well as through design and mixture improvements.
Project Design and Layout
The pavement design consists of a 220-mm (8.7-in.) slab with 4.6-m (15-ft) joint spacing, a dense cement treated base, 32-mm (1.25-in.) diameter dowels spaced at 305 mm (12 in.), and a tied concrete shoulder. The transverse and longitudinal joints are sealed with a preformed compression seal and a low-modulus hot-poured material, respectively.
A definite correlation has been shown between monitoring of the smoothness behind the paver and the head of concrete coming into it. A special strike-off bar is being developed to maintain a uniform head of concrete to help alleviate one significant source of roughness. Concrete mixtures have been improved by newer specifications in Kansas, but there still appears to be room for making the mixture more workable without being susceptible to segregation. This will be done by increasing the coarse aggregate content to the maximum possible, while maintaining a non-segregating grading without gaps. Consistency of the mixture and the paving operation along with ambient temperatures must also be monitored for any effect on smoothness. The smoothness of the paving base should also be checked.
During the post construction period, the temperature gradient in the slab will be measured for morning and afternoon placements. Daily temperature ranges (and solar radiation) can also be monitored for their effect on smoothness. Additionally, joint spacing can be varied somewhat, from a standard spacing of 4.6-m (15 ft) to as short as 3.6 m (12 ft) and as much as 5.2 m (17 ft) for each of the three mixtures proposed for the project.
State Monitoring Activities
No information is currently available regarding the State monitoring efforts.
Preliminary results are not available at this time.
Point of Contact
Chief of Materials and Research
Kansas Department of Transportation
Bureau of Materials and Research
2300 Van Buren
Topeka, KS 66611-1195