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Presented at: Rutgers Asphalt Paving Conference March 8, 2011 Presented by: Eileen Sheehy, P.E. Manager, Bureau of Materials NJDOT.

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Presentation on theme: "Presented at: Rutgers Asphalt Paving Conference March 8, 2011 Presented by: Eileen Sheehy, P.E. Manager, Bureau of Materials NJDOT."— Presentation transcript:

1 Presented at: Rutgers Asphalt Paving Conference March 8, 2011 Presented by: Eileen Sheehy, P.E. Manager, Bureau of Materials NJDOT

2 Topics for Discussion Warm Mix Asphalt Independent Assurance Coring Ride Quality Specification Asphalt Binders for Performance Based Mixes Current HMA Research Performance Based Specifications RAP in HMA Northeastern States’ RAP Pooled Fund Study

3 Warm Mix Asphalt NJDOT has done some warm mix asphalt trials over the past 3 years. Most extensively used to aid in compaction for late season paving or in specialty mixes to reduce the laydown temperature. All trials used additives – either surfactants or waxes. FHWA support of WMA as part of Every Day Counts initiatives. NJDOT/NJAPA/FHWA Task Force established November 2010 to implement WMA on NJDOT projects.

4 Warm Mix Asphalt Task Group Task Group is working on a specification to be put out for bid on 3-6 projects this coming year. Proposed specification allows a trial of any WMA technology. Extra samples are need of both the WMA and the HMA on the project to further the research being done. In addition, NJDOT will entertain proposals from contractors to try WMA on projects that call for HMA mixes. Foaming systems will be considered.

5 NEAUPG WMA Task Group The Northeastern Asphalt User/Producer Group has formed a task group to consider a more uniform approach to WMA in the Northeast. Preliminary discussions are to have a region-wide approved products list (or qualified products list). Consideration is being given to following the NYDOT protocols for approving technologies. Task Group has been working on a definition of WMA.

6 Independent Assurance Program for Coring NJDOT will continue the Independent Assurance Program for Coring in FHWA requires IA on Federally funded projects. NJDOT usually uses the same IA Programs on State funded projects. NJDOT has a Consultant on board to take Independent Cores for testing in the NJDOT Laboratory and perform analysis of the results.

7 Ride Quality Specification Presentation from last year gave the background of the new IRI specification for pavements. Set targets based on number of lifts of paving, IRI of existing road, etc. Based on the amount of “impediments” (obstacles to good paving), lots will be excluded from pay adjustment. Expect to see the new specification in all future projects, so please review the special provisions for projects to know what the ride quality specification is for a project.

8 New IRI Specification Example Excluded Lots Pay Equations for Pavement Ride Quality for 0.01 Mile Route 00 NB MP 5.0 to MP Route 00 SB MP 10.0 to MP in Lane 1 3 in Lane in Lane 1 15 in Lane 2 IRI < 28PA = $50 28 < IRI < 48PA = $ – ($2.5 x IRI) 48 < IRI < 58PA = $0 58 < IRI < 128PA = (IRI – 58) x (– $7.1429) IRI > 128Remove & Replace

9 Setting the Target IRI The proposed model is of the following form: IRI SPECIFIED = (IRI BASELINE ) (A 1 ) (A 2 ) (A 3 ) … (A k ) Where, IRI BASELINE = standard level of IRI desirable for pay- adjustment = $0.0 IRI SPECIFIED = adjusted level of IRI to be specified based on project-specific conditions A i = factors (variables) that are project specific k = Number of different factors in the equation

10 Generalized Factors Factor Symbol Speed Limit (MPH)ASAS No. of OperationsAOAO Existing Roughness (IRI)AEAE Composite PavementACAC

11 Speed Limit Factors

12 Factor for Number of Operations  Number of operations is defined as the number of improvement events.  For example, milling 2" followed by an overlay of 2" is considered to be 2 operations.  Or, milling 2" followed by paving 2" of intermediate and 2" of surface is considered to be 3 operations.

13 Factor for Existing Roughness  This factor recognizes the difficulties in achieving a smooth pavement when the existing pavement is rough.  The “number of operations” (A O ) and the “existing roughness” (A E ) are inter-connected factors and consideration of both factors contribute to determining the target IRI.

14 Combined Number of Operations and Existing Roughness Factor

15 Composite Pavement Factor  If the overlay on bare PCC pavement is > 8", exclude using a composite pavement factor.  If an existing overlay is to be resurfaced with or without milling, the composite pavement factor should not be applied if the total HMA thickness is > 8“ after the overlay.

16 Localized Factors Used to Determine Excluded Lots

17 Example of Excluded Lots Calculations

18 New IRI Specification Example Excluded Lots Pay Equations for Pavement Ride Quality for 0.01 Mile Route 00 NB MP 5.0 to MP Route 00 SB MP 10.0 to MP in Lane 1 3 in Lane in Lane 1 15 in Lane 2 IRI < 28PA = $50 28 < IRI < 48PA = $ – ($2.5 x IRI) 48 < IRI < 58PA = $0 58 < IRI < 128PA = (IRI – 58) x (– $7.1429) IRI > 128Remove & Replace

19 Asphalt Binders for Performance Based Mixes When the specification for a mix is based on performance testing of the mix (e.g., BRIC, BRBC, BDWSC), the actual binder needed will depend on the mix design. A minimum grade binder is listed in the specification, but the precise binder that will be needed will depend on the mix design, the formulation of the binder, and the performance testing of that mix.

20 Asphalt Binders for Performance Based Mixes With an optimized mix design, a less modified binder may work, but a more modified binder may be needed if the mix design is not optimum. HMA Supplier should work with the Binder Supplier to develop a mix that will meet all performance testing for the mix.

21 Performance Based Specifications Research New research project starting this year to look at the following: Existing NJDOT performance based mix requirements. Performance based specifications for “regular” mixes. Use of performance based specifications to eliminate prescriptive aspects of NJDOT specifications. Research being done by Rutgers. Research is expected to last 2 years.

22 RAP in HMA Research Project Study being done by Rowan University. 2 year study will be complete July Findings to date: There is incomplete blending of the RAP binder with the virgin binder. Only partial credit should be considered for the RAP binder. Quality Control is important. Amount of RAP allowed should be linked to variability of the RAP stockpile.

23 Northeastern States’ RAP Pooled Fund Study Many of the Northeastern States (including NJDOT) are involved in a Pooled Fund Study looking at use of higher percentages of RAP (>25%). Work being done at University of New Hampshire with assistance by Rutgers University.

24 Thank you for your attention!


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