Final Report 2000-02

Minne-ALF Project Overview and Retro-Fit Dowel Study Results

Technical Report Documentation Page

1. Report No. 2. 3. Recipient’s Accession No.

MN/RC - 2000-02

4. Title and Subtitle 5. Report Date

MINNE-ALF PROJECT OVERVIEW AND RETRO-FIT December 1999 DEWEL STUDY RESULTS 6.

7. Author(s) 8. Performing Organization Report No.

Rebecca A. Embacher Mark B. Snuyder

9. Performing Organization Name and Address 10. Project/Task/Work Unit No.

University of Minnesota Civil Engineering Department 11. Contract (C) or Grant (G) No. 500 Pillsbury Drive, S.E. Minneapolis, MN 55455 c)72272 wo) 146

12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered

Minnesota Department of Transportation Final Report 1994-1999 395 John Ireland Boulevard Mail Stop 330 14. Sponsoring Agency Code St. Paul, Minnesota 55155

15. Supplementary Notes

16. Abstract (Limit: 200 words)

A laboratory-based linear loading pavement test stand, the Minnesota Accelerated Loading Facility (Minne-ALF) simulates the passage of heavy traffic loads moving at speeds up to 65 kph (40 mph) over small, full-scale pavement test slabs. Hydraulic actuators control a rocker beam, which simulates loads. Researchers simulated the passage of 40-KN (9-kip) single-wheel loads at a rate of 172,000 per day, although wheel loads up to 100 kN (22 kips) can be simulated at varying speeds. Full-axle simulations are possible with frame modifications.

Concrete slabs were cast and dowels were installed in slots across crack/joints. Test variables included joint fact texture, repair backfill material, and dowel material and length. Test outputs included measurements of load transfer efficiency and differential deflection across the joint/crack.

The effect of joint/crack face texture was great when the joint/crack remained tight. Load carrying performance was improved using Speed Crete 2028 in place of 3U18 concrete backfill with similar joint and dowel bars. Load transfer was unaffected by the use of stainless steel-clad dowel bars in lieu of epoxy-coated dowel bars. Researchers recommend additional testing to examine the effects of dowel length and dowel materials

17. Document Analysis/Descriptors 18. Availability Statement Retrofit dowls Load transfer Accelerated pavement testing Differential deflection No restrictions Document available from: National Technical Information Services, Springfield, Virginia 22161

19. Security Class (this report) 20. Security Class (this page) 21. No. of Pages 22. Price

Unclassified Unclassified 97