1. a Guidance, Parameters & Recommendations for Rubblized Pavements July 2006

2. a Wisconsin Highway Research Program Wisconsin Department of Transportation Project IC 0092-05-07 By: Harold L. Von Quintus, P.E. Jagannath Mallela Brian Aho Chetana Rao Guidance, Parameters & Recommendations for Rubblized Pavements

3. a Expanding the Realm of Possibility Presentation Overview 1.Objectives 2.Data Collection 3.Performance Analyses 4.Summary of Findings

4. a Expanding the Realm of Possibility Project Objectives 1.Document historical information on the rubblization projects in Wisconsin. 2.Provide guidelines for the selection, design, testing, and construction of rubblized PCC pavements. 3.Determine conditions for which rubblizing PCC is a feasible rehabilitation strategy.

5. a Expanding the Realm of Possibility Products Final Report – Guidance, Parameters, & Recommendations for Rubblized Pavements. Guidelines for Designing & Constructing Rubblized PCC Pavements, Appendix A. Catalog of Performance History & Details of Wisconsin’s Rubblized Projects, Appendix B.

6. a Expanding the Realm of Possibility Rubblization Definition: Fracturing the PCC slab in place into fragments of nominal 3 to 8 inch size or less while retaining good interlock between the fractured particles. Purpose: Eliminate reflection cracking in an HMA overlay by destroying the integrity of the PCC slab.

7. a Expanding the Realm of Possibility Rubblization Projects > 20 Projects > 5 but < 20 Projects

8. a Expanding the Realm of Possibility LTPP SPS-6 Projects – Distress Summary LCNWP: Traffic & structure independent. LCWP: > 4 inches is adequate.

9. a Expanding the Realm of Possibility LTPP SPS-6 Projects – Distress Summary LTPP data inconclusive, other than transverse cracking dependent on HMA overlay thickness. Fatigue cracking is traffic dependent.

10. a Expanding the Realm of Possibility Rubblization Timeline in Wisconsin 198819901992199419961998200020022004 1010330143411108712 Demo I-43 1 st Project RFB 1 st Project MHB No. of Rubblized Projects Increase RFB & RFB + Guillotine Increase Thick. Adopt PG Spec. Adopt Mix Spec. Number of Rubblized Projects

11. a Expanding the Realm of Possibility Project Identification & Data Collection 1. Identify rubblization projects in Wisconsin.  PMS database  Industry 2. Project summary sent to regions for confirmation. 3. Review historical or time series performance data to identify discrepancies. 4. Resolve discrepancies. 5. Prepare final listing of rubblization projects & create database.

12. a Expanding the Realm of Possibility Project Identification & Data Collection: Summary of Discrepancies Between Data Sources Rubblization year? Performance data does not make sense with year of rubblization? Rehabilitation strategy inconsistent with database – change order?

13. a Expanding the Realm of Possibility Project Identification & Data Collection: Projects Used in Analyses No conflicting information between data sources. Best available data and information on each PM segment. Performance data for each PM segment within project limits used in determining average values for project.

14. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – Number of Projects Relatively few projects are > 7 yrs. old!

15. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – Unit Costs, 1998 – 2004

16. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – Unit Costs, 1998 – 2004

17. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – HMA Overlay Thickness Thicker HMA overlays used in recent years!

18. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – HMA Overlay Thickness HMA Overlay Thickness increased in 1998. 2 to 5.5 in. 3 to 6.5 in.

19. a Expanding the Realm of Possibility Performance Indicators Used in Analysis Extracted from Wisconsin’s Pavement Management Database IRI Values – Less than 4% of rubblized segments have IRI > 140 in./mi. Rut Depths – Less than 10% of rubblized segments have rut depths > 12 mm. PDI Values – Less than 5% of rubblized segments have PDI values > 50.

20. a Expanding the Realm of Possibility Rubblized Project: SQNO – 10390 Year – 1997 HMA Overlay = 3 in. Performance Data Key Issues: ●Data Variability ●Discrepancies ●Missing Data

21. a Expanding the Realm of Possibility Rubblized Project: SQNO – 11910 Year – 1998 HMA Overlay = 5.5 in. Performance Data Key Issues: ●Data Variability ●Discrepancies ●Missing Data

22. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 Rut Depths. Most projects have minor rut depths, with exception of the older projects!!

23. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 Distress Values. Older projects have higher amounts of distress!!

24. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 IRI Values. Most projects are still smooth!!

25. a Expanding the Realm of Possibility Summary of Wisconsin’s Rubblization Projects Over 50% of rubblized segments are less than 5 years in age. 60% of rubblized segments have no cracking. 50% of rubblized segments have rut depths < 6 mm. 65% of rubblized segments are smooth with IRI values < 80 in./mi. Rubblized projects are relatively new for the above to be meaningful.

26. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 IRI Values.

27. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 IRI Values. IRI increases with age, but other confounding factors!

28. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 IRI Values.

29. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 Rut Depths.

30. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 Rut Depths. Older projects built under previous specs. have the greater rut depths!!

31. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 Rut Depths.

32. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects – 2004 Distress Values.

33. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 PDI Values.

34. a Expanding the Realm of Possibility Overview of Wisconsin’s Rubblized Projects: 2004 PDI Values.

35. a Expanding the Realm of Possibility Summary: Rubblized Segments Performing Better Than other Rehabilitation Strategies! Performance Indicator & Criteria Expected Service Life, yrs. PDI, 5013 IRI, 140 in./mi.16 Rut Depth, 12 mm10 Older sections heavily influence extrapolated service life, because of higher distress. BUT, Average Service Life is low!!

36. a Expanding the Realm of Possibility Rubblization Timeline in Wisconsin 198819901992199419961998200020022004 1010330143411108712 Demo I-43 1 st Project RFB 1 st Project MHB No. of Rubblized Projects Increase RFB & RFB + Guillotine Increase Thick. Adopt PG Spec. Adopt PG Spec. Number of Rubblized Projects CONFOUNDINGFACTORSCOMPLICATE THE ANALYSIS!

37. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects: Before & After 1997. Change in HMA mixtures:  Performance-Graded binders  Mixture design criteria  Thicker HMA overlays

38. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – HMA Overlay Thickness

39. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – Extrapolated Service Life Must stratify projects into groups with similar HMA mixture specifications & overlay thickness. If excessive rutting does not occur within the first 4 years, excessive rutting probably does not occur. If HMA overlay is built smooth, it will remain smooth until other distresses begin to occur.

40. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – Extrapolated Service Life Where: t= Age in years t design = Design life in years a,b= Regression coefficients

41. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – Extrapolated Service Life

42. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – Extrapolated Service Life

43. a Expanding the Realm of Possibility Wisconsin’s Rubblized Projects – Extrapolated Service Life Age & mix properties are dominant factors. HMA thickness minor factor.

44. a Expanding the Realm of Possibility Expected Service Life Based on Elastic Modulus & Damage Tensile strain at bottom of HMA overlay Elastic modulus of rubblized PCC; 35 to 120 ksi Average elastic modulus of rubblized PCC – 65 ksi

45. a Expanding the Realm of Possibility Expected Service Life Based on Damage & Elastic Modulus, yrs. Time HMA Thick., in. Design Traffic, MESALs 31030 1990 to 1997 31752 5>30145 6.5>303010 1998 to 2003 32162 5>30227 6.5>30 18 Changes made around 1997 were very beneficial to HMA performance!!

46. a Expanding the Realm of Possibility Comparison of Average Service Lives from Different Studies AgencyService Life, years Wisconsin, Rubblization Study 18 to 21 Asphalt Institute 22 Michigan 14 to 18 Wisconsin; SMA Study, non- rubblized PCC pavements 12 to 16 Wisconsin; Service Life Study 15 to 25

47. a Expanding the Realm of Possibility Performance Analysis Summary 1990 to 1997 projects; expected service life equals 13 years. Projects built after 1997; expected service life exceeds design life. NEEDS TO BE CONFIRMED WITH DATA. Age & mix are predominant factors; insufficient number of projects to determine effect of other factors. Predominant distress types are longitudinal cracking outside wheel path & transverse cracking.

48. a Expanding the Realm of Possibility Performance Analysis Summary Rutting not a controlling factor. Average elastic modulus of rubblized PCC layer is 65 ksi, Recommended value for design. CONFIRM WITH DATA Minimum in place modulus of foundation is 15 ksi. Minimum HMA overlay thickness is 4 inches. NEEDS TO BE CONFIRMED WITH DATA.

49. a Expanding the Realm of Possibility Summary YES Is rubblization a cost effective strategy? – YES Parameters to be considered: Detailed site investigation Detailed site investigation Minimum foundation modulus = 15 ksi Minimum foundation modulus = 15 ksi Recommended values for design: AASHTO structural layer coefficient = 0.20 AASHTO structural layer coefficient = 0.20 Elastic modulus of PCC layer = 65 ksi Elastic modulus of PCC layer = 65 ksi Problems encountered with rubblization: HMA overlay too thin HMA overlay too thin Omission of drainage layers Omission of drainage layers Localized soft spots in foundation Localized soft spots in foundation

50. a Expanding the Realm of Possibility Summary Types of test and frequency – Insufficient data from Wisconsin projects. Test strip for each foundation and PCC thickness Deflection basin tests, 100 to 200 ft interval Data to monitor for confirming rehab strategy – Insufficient data from Wisconsin projects. Deflection basin data Gradation of rubblized layer Volumetric properties of HMA Distress with time

51. a Expanding the Realm of Possibility Summary Changes made between 1997 to 2000 have been effective in increasing the performance of HMA mixtures and rubblized PCC pavements.

52. a Expanding the Realm of Possibility Recommendations Continue to use PCC rubblization as a rehabilitation strategy of deteriorated PCC slabs. Continue to monitor existing and future rubblization projects to confirm findings.

53. a Expanding the Realm of Possibility Final Recommendation Issue – Data Quality: Discrepancies & conflicting information, common data problems with large or network databases. LTPP Database PMS database; Colorado, Missouri, Montana, Texas Suggested Resolution; 1. Hire graduate student or issue annual contract to:  Continually monitor database  Focal point to receive errors and anomalies  Make corrections to databases  Make recommendations for improving database use 2. Allow consultants to review electronic as-built construction plans. Result 1. Will receive a better product from research studies. 2. Will cost less in the long run. 3. Database becomes user friendly & implementation is focused.

54. a Expanding the Realm of Possibility Questions!