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Pavement Performance Specifications Research.

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Presentation on theme: "Pavement Performance Specifications Research."— Presentation transcript:

1 Pavement Performance Specifications Research

2 Asphalt Pavement Facts
FDOT: 5 million tons asphalt per year Approximately $500 million 300 construction projects 96% of pavements in Florida are asphalt 93% of pavements in US are asphalt It’s 100% recyclable (RAP) Typical life-span in Florida is 17 years

3 Statewide Pavement Performance
Section of Florida Statutes: “Ensuring that 80% of the pavement on the SHS meets Department Standards”

4 Statewide Pavement Performance

5 Deficient Roadways Some may think that we are getting better and better due to the fact that we are resurfacing more and more. This actually shows that not to be true. We are resurfacing about the same # lane miles per year (bar chart) and our # deficient lane miles is declining (line graph). With the new system of the resurfacing program being 25 years, and more of the work program being focused on capacity, the line may go up slightly; the bar graph will decrease.

6 Asphalt Specifications Update
January 2013 – July 2014

7 January 2013 Workbook Section 300 – Prime and Tack Coats
Approved NTSS-1hm (trackless tack) as prime coat Tack all asphalt layers (clarification)

8 January 2013 Workbook Section 320 – Hot Mix Asphalt – Plant Methods and Equipment No more viscosity testing of RAP every 5000 tons (Materials Memo 01-13) Can use loaded aggregate trucks for scale checks. Modified wording related to release agents; banning petroleum based products, not just “diesel fuel”

9 January 2013 Workbook Section 330 – Hot Mix Asphalt - General Construction Requirements Eliminated mandatory requirement to perform QC rolling straightedge testing on friction course if final acceptance is by laser profiler Can only mill out high straightedge deficiencies. No milling of “two highs” to fix a low deficiency

10 Asphalt Binder Grade for Mixes Containing RAP
January 2013 Workbook Section 334 – Superpave Asphalt Concrete Lowered minimum overbuild thickness for SP-12.5 to ½” Removed Ninitial requirements Table 334-2 Asphalt Binder Grade for Mixes Containing RAP Percent RAP Asphalt Binder Grade 0 - 15 PG 67-22 PG 58-22 >30 PG 52-28

11 January 2013 Workbook Section 334 – Superpave Asphalt Concrete
No density testing if less than 50 tons of “density mix” in a sublot No more pro-rating LOT pay factors by density required/no density required areas. Entire LOT gets pay factor unless entire LOT is no density required

12 January 2013 Workbook Section 916 – Bituminous Materials
Elimination of RA viscosity graded binders. Now all binders are PG graded Removed RA-500, RA-750, RA-1000, RA-1500 and replaced with PG and PG 58-22 No longer using PG for HMA Eliminated net total of three binders Materials Memo issued to allow use on contracts let prior to January 2013

13 July 2013 Workbook Section 234 – Superpave Asphalt Base
Can substitute a SP-12.5 Traffic Level D or E mixture in lieu of a Type B-12.5 mixture, not to exceed 500 tons for a project, at no extra cost to the Department, in limited situations if approved by the Engineer Section 320 – Hot Mix Asphalt – Plant Methods and Equipment Cover and tie down all loads of friction course

14 July 2013 Workbook Section 330 – Hot Mix Asphalt - General Construction Requirements Moved FC-5 temperature requirements from 337 to 330

15 July 2013 Workbook Section 334 – Superpave Asphalt Concrete
Variable thickness overbuild layers constructed using a Type SP-9.5 or SP-12.5 mixtures may be tapered to zero thickness provided a minimum of 1-1/2 inches of dense-graded mix is placed over the variable thickness overbuild layer Pavement Composition Report changed to Pavement Coring Report

16 July 2013 Workbook Section 336 – Asphalt Rubber Binder
Eliminated ARB-5 and ARB-12 Section 916 – Bituminous Materials Addition of “PG (ARB)” to replace ARB-5 and ARB-12 Requirements for “PG (ARB)”: Minimum 7% GTR. Certification Optional polymer modification, if needed Must meet the requirements for PG 76-22 Additional “separation” requirement to minimize settlement

17 July 2013 Workbook Section 916 – Bituminous Materials
Previous PG with SBS polymer renamed to PG (PMA) PG (PMA) added to standard specification Implementation of Multiple Stress Creep Recovery (MSCR) tests for modified binders only Polyphosphoric acid (PPA) may be used as a modifier not exceeding 1.25% by weight of asphalt binder

18 July 2013 Workbook Section 919 – Ground Tire Rubber
Modified gradation requirements (only max particle size; 98% passing no. 30 sieve) Removed mandatory ambient grinding requirement Changed maximum Rubber Hydrocarbon Content from 55% to 60% to reflect modern day tires

19 January 2014 Workbook Section 320 – Hot Mix Asphalt – Plant Methods and Equipment Allows the first five loads of WMA to be produced at HMA temperature for purposes of heating the paver. Mix temperature not to exceed 330°F Section 330 – Hot Mix Asphalt - General Construction Requirements Do not use diesel fuel or other petroleum based solvents contained in an open container for cleaning purposes on the paver

20 January 2014 Workbook Section 334 – Superpave Asphalt Concrete
Removed coarse graded mixtures Increased maximum lift thickness of fine graded SP-19.0 mix type from 3" to 3-1/2" because coarse graded mixtures were removed Section 337 – Asphalt Concrete Friction Courses Increased maximum possible design AC content for granite FC-5 mixtures from 7.0 to 7.5%

21 January 2014 Workbook Section 916 – Bituminous Materials
Added a statement that excess PG (ARB) could be mixed with unmodified binder under the conditions outlined in the specification

22 July 2014 Workbook Section 300 - Prime and Tack Coats
Removed cut-back prime coats and emulsion grades not being used any more Added two new trackless tack products Section 320 – Hot Mix Asphalt – Plant Methods and Equipment Added language "For warm mix asphalt, the Contractor may produce the first five loads of the production day and at other times when approved by the Engineer, at a hot mix asphalt temperature not to exceed 330°F for purposes of heating the asphalt paver

23 July 2014 Workbook Section 334 – Superpave Asphalt Concrete
Added clarification for SP-19.0 mixtures: "Type SP May not be used in the final (top) structural layer below FC-5 mixtures. Type SP-19.0 mixtures are permissible in the layer directly below FC-9.5 and FC-12.5 mixtures." Set time limit of 60 days for how long a LOT can be left open.

24 July 2014 Workbook Section 916 – Bituminous Materials
Removed cut-backs, some emulsions, and added trackless tacks Emulsions now approved and monitored like binders. Added to the QPL. For PG (ARB), provide a certification statement on the product evaluation application and in the Quality Control Program that a minimum of 7.0% GTR is used in the formulation of the binder.

25 Hot Topics & Research Notables

26 NCAT Test Track 20” of asphalt base  insures all failures are in the top 4” asphalt structural layers. One truck = six fully loaded 18- wheelers (152,000 lbs.) Five trucks are operational at one time. ≈ 45 mph. Load 5 AM to 11 PM. Two shifts per day miles per driver per day. 6 days per week. 3 year research cycle 10 million ESALs applied over two years. (10.36 ESALs per pass) Forensics and reconstruction on 3rd year. Florida Department of Transportation

27 NCAT Test Track Fine vs. Coarse (PG 67-22) Continuation of 2000 cycle PG vs. PG 76-22 Validation of SMO HVS Validation of Energy Ratio Bonded Friction Course Thick tack coats Polymer vs. Rubber High RAP vs. Shingles Florida Department of Transportation

28 Pavement Preservation
Traditionally FDOT has focused on milling and resurfacing Higher traffic volume roadways Goal: Get in, get out, stay out… We technically do very little “traditional” pavement preservation. Mainly because of the high traffic levels. The public doesn’t understand why FDOT shuts down lanes, and works on a road (pavement preservation) and then five years later are out there again. Because of our good high quality subgrades and bases, our pavements generally function like perpetual pavements. Majority of the distress is within a few inches of the surface.

29 Hot-In-Place Recycling
FDOT looking at alternatives… Hot-In-Place Recycling Microsurfacing We’ve done a bunch of HIPR since 2001 (we did HIPR prior to that, but it was really outdated technology in the 70’s and early 80’s.) Some turned out well – SR-471 in Sumter County was reworked in 2002 and is 11+ years old; some didn’t - CR-315 in Putnam County was reworked in 2001 and failed within a few months. Crack Sealing Fog Seal

30 Hot in-Place Recycling
12 projects* constructed to date: 11 as “Reworked Asphalt” 1 as “Repaved Asphalt” Every district except for Turnpike Earliest project* 2001 Four projects completed in 2012 * “Modern” Era We’ve done a bunch of HIPR since 2001 (we did HIPR prior to that, but it was really outdated technology in the 70’s and early 80’s.) Some turned out well – SR-471 in Sumter County was reworked in 2002 and is 11+ years old; some didn’t - CR-315 in Putnam County was reworked in 2001 and failed within a few months.

31 Microsurfacing First FDOT microsurfacing project:
US-319 Leon County 2010 Worked with several Contractors & Suppliers on specification Based on ISSA requirements ISSA Type II mixture gradation Spread rate 20 – 26 lbs/sy Single course Required crack sealing We did a micro-surfacing job on US-319 in Leon County in Cracks have all reflected up through the surface. We may have selected a job that was too cracked to begin with, plus it was only a single course. March 2014 project in Gainesville on NW 39th Avenue. It’ll be double course.

32 Crack Sealing Five Crack Seal Test Decks were placed in March 2012
Leon, Baker, Sumter, DeSoto, and Miami-Dade Counties Several materials and construction techniques evaluated Performance will be monitored for three to five years We did a number of crack sealing projects around the state in We’re monitoring them to see if they are effective. Typically cracks are sealed to keep water out of the base, and since our cracking is generally top down, we’re not sure that it’ll do much good. But we’ll see if it slows the crack growth. Crack seal test decks were constructed at five locations statewide: SR 61, Leon County SR 121, Baker County SR 471, Sumter County SR 72, Desoto County SR 997, Miami-Dade County Each test deck is 1.25 miles in length and consists of only one lane. The test decks are divided into five 1/4-mile segments.  From south to north (or west to east) the five segments are the same at each location: Segment 1: Routing and sealing with asphalt rubber binder Segment 2: Crack filling with asphalt rubber binder Segment 3: Control (no work) Segment 4: Routing and sealing with polymer modified binder Segment 5: Crack filling with polymer modified binder Construction occurred at all five locations in March 2013. Monitoring of each location will occur annually for a period of 3-5 years. Initial project selection criteria included roadway segments that had a 2012 crack rating between 7.0 and 8.0, a ride rating of 7.2 or better, and a rut rating of 9 or 10.  Only dense graded friction courses were considered. Friction measurements were taken within 1-3 months of construction at all five locations.  In comparison with the previously recorded friction measurement for each roadway segment, the average reading for the five sections were: +3.6, -0.6, +1.4, +2.6, and -4.6.  I haven’t discussed the ramifications of these measurements with anyone, and I would hesitate to make any generalizations, but I do not see any discernable pattern with the data, and they all appear to be relatively close to the baseline measurements. Crack, ride, and rut measurements were taken for each segment (25 total) about three months prior to construction and about 2-3 months after construction.  A comparison of the before and after measurements for the 20 segments that received treatment follows: Average IRI for each segment increased by 5.1 after construction.  Over half of that increase came from four specific segments found in the first two jobs that were constructed.  It appears from the data (and it appeared to me in the field) that once the guy working the wand became comfortable with the process and what I was looking for, that we got a much smoother product.  The average IRI increase for segments found in the final three jobs was only 2.6. Average Ride Number (RN) for each segment decreased by 0.14 after construction.  This would correspond with an average decrease in ride rating of 0.28.  However, looking only at the final three jobs, the average RN for each segment decreased by only 0.07, which corresponds with an average decrease in ride rating of 0.15. Average rut rating was not affected by the installation of crack sealing. The final crack rating did not change for 18 of the 20 segments.  However, an improvement in crack rating would not be expected immediately for roads with generally light crack severity.  An improvement in crack rating would be evidenced over time, by comparison to the control section, which we would expect to deteriorate to moderate or severe cracking, while the test sections might be expected to maintain their “light cracking” status for a longer period of time.

33 Fog Sealing Test Sections
Placed in 2013 US-27 & US-17 Polk County Placed on OGFC Attempt to reduce raveling & top-down cracking Age: 4 years old Good condition Multiple Test Sections Multiple Products We’re looking at fog sealing (at an early age) to see if it’ll extend the life of the pavement by either preventing raveling or top down cracking. The problem with fog sealing is the fairly dramatic loss of friction on the surface. It gets better in a few days/weeks but it’s a pretty high risk. Friction numbers can go down anywhere from 2 points down to 15 points (i.e., 40 to a 25), depending on the production.

34 Pavement Preservation Test Sections
US-98 Gulf County Constructed 2012 Ten Test Sections: Control Section Micro-surfacing (Double course) 1/2” HMA overlays with 4.75 mm mix 3/4” HMA overlays with 4.75 mm mix 1” HMA overlay with 9.5 mm mix Hot-in-place recycling Bonded open graded friction course Mill and resurface 1.0” with 9.5 mm mix Mill and resurface 1.5” with 12.5 mm mix Control section We did a controlled experiment on US-98 in Gulf County. Construction was in Dec 2012 – Tried a number of things. Each section was 0.1 mile long. One Year PCS survey is coming up – they had equipment issues in December. This project will help guide FDOT’s direction on preservation.

35 Recycling Program

36 RAP Data Conditions FY 10/11 FY 11/12 FY 12/13 FY 13/14 Unrestricted
(No Maximum Limit) Average 25% 26% Maximum 40% 38% 39% 41% Restricted (Maximum 20%) 17% 18% 16% 15% 20%

37 RAS National Hot Topic FDOT pilot projects 0.85 Binder Availability
Issues with the unknown

38 NCAT: High RAP versus RAP/RAS
PG (PMA) with 25% RAP PG (PMA) with 20% RAP & 5% RAS

39 Pavement Segregation January 2012 specification Texture Meter
Pave-IR System

40 Pave-IR Demo Oct. 2013 / Turnpike, Palm Beach Equipment: MOBA Pave-IR
To detect Thermal Segregation

41 Bonded Friction Course
Conventional Trackless UltraFuse eTac Florida Department of Transportation

42 Other Research Binder Rejuvenators
Optimization of FC-5 characteristics Field test method to detect Polymer and/or GTR Performance Specification for Tack – Bond Strength FC-5 image analysis for determination of optimum binder content Understanding mechanisms of OGFC raveling New Flow Number (FN) Test: iRLPD Hydrated Lime Study Volumetric refinement Alternative technique(s) to mitigate reflective cracking RAP with Dense-graded FC Evaluation of FL mixes for crack resistance using Overlay Tester

43 Questions/ Comments? Thank You!

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