Quantifying the Benefits of Polymer Modified …

1 Quantifying the Benefits of Polymer Modified AsphaltP3 SymposiumLaramie WyomingJuly 15, 2009 David R. Johnson, Engineer, asphalt InstituteBillings MontanaOverview PMA Performance Study Quantifying the Benefits of PMA 1stArticle Reprint LCCA Basics Review Understanding the True Economics of Using PMA through LCCA 2ndArticle Reprint ExampleDesign Engineer s Perspective PMA is One of Many Tools Available Performance Benefits Acknowledged Many Lab and Field Studies Still, the Big Question Remains: How Do I Quantify the Benefits of PMA?Quantifyingthe Effects ofPMAforReducing PavementDistressThis study (published by AI in Feb 2005) uses national field data to determine enhanced service life of pavements containing Polymer Modified binders versus conventional binders.

2 The data is from a variety of climates and traffic volumes within North 215 Exec. Summary Full Report Same study documented in 2007 TRB Paper (07-3230): Quantification Of The Effect Of Polymer Modified asphalt On Flexible Pavement Performance Study SponsorsIndustry Associations The asphalt Institute The Association of Modified asphalt ProducersFederal Highway AdministrationCorporate Sponsors Arr-Maz Products ATOFINA Petrochemicals, Inc. Dexco Polymers LP Dynasol LLC KRATON Polymers Polimeri Europas Americas UltrapaveStudy TeamProject Team PI: Harold L. Von Quintus, Associate: J. MallelaStudy the effect of using PMA as compared to conventional-unmodified HMA mixtures in terms of: Reducing occurrence of distresses Increasing pavement conditions that maximize effect of PMA to increase pavement & overlay life PMA more effective in certain conditions, and less effective in othersAgency Survey: Reasons for Using PMA?

3 020406080100 RTFMDRTR esponse, %R = RuttingT = Thermal CrackingF = Fatigue CrackingM = Moisture Damage or StrippingD = DurabilityR = RavelingT = TendernessNo one cited reduced fatigue crackingField Test Sections FHWA s LTPP SPS-1; SPS-5; SPS-6; SPS-9 GPS-1; GPS-2; GPS-6; GPS-7 Modifier Study Accelerated Pavement Tests FHWA ALF NCAT Test Track California HVS Studies Ohio Test Road Corp of EngineersLocations of Test Sections-PMA and At Least One Unmodified CompanionNot all 84 sections located on Surface Distress Data Collected/ Compared Fatigue Cracking Rutting Thermal CrackingIn this studyAlready Thru LT PPExperimental Factorial 32 CellsPavement Cross SectionBase FoundationClimateFreezeNon-FreezeWetDryW etDryThin HMA (<4 )Fine-Grained2243 Coarse-Grained3333 Thick HMA (4-8 )Fine-Grained2223 Coarse-Grained2232 Full-Depth (>8 )

4 Fine-Grained0122 Coarse-Grained0122 HMA OverlaysHMA3366 PCC434484 Total PMA and Companion Sections16172625 Direct Comparisons Depths on PMA Sections, inchesRut Depths on Companion Sections, inchesLine of equality- age of these sections variesDistress Comparisons Transverse Cracking - PMA Sections, Cracking - Companion Sections, of equalityDistress Comparisons Fatigue Cracking Cracking - PMA Sections, %Fatigue Cracking - Companion Sections, %Line of equalityDirect Comparisons Useful, But Still Have NOT Quantified Extended Service Life of PMA Cracking - PMA Sections, %Fatigue Cracking - Companion Sections, %Years for equal cracking???Mechanistic-Empirical Analysis Use distress prediction models from new Pavement Design Guide for: Fatigue Cracking Rutting Damage Indices (DI =n / Nf) computed using factorial cell specific calibration For each of the 32 cells Compare DI to the actual field distress measurements for both PMA and unmodified sections to obtain different expected service lives Summaryof Expected Increase in Service Life, Years, Based on M-E Damage Based AnalysisSite FactorCondition DescriptionAdded LifeFoundationNon-expansive, coarse soils5-10 Expansive and plastic soils (PI>35) 2-5 Frost Susceptible in cold climate2-5 Water Table & DrainageDeep5-10 Shallow; adequate 5-8 Shallow.

5 Inadequate0-2 Existing Pavement ConditionHMAGood5-10 Poor-extensive cracking1-3 PCCGood3-6 Poor-faulting & cracking0-2 Assumptions: Unmodified mixes designed for 20 yrs, PMA in wearing surface and basesContinued: Summaryof Expected Increase in Service Life, YrsSite FactorCondition DescriptionAdded LifeClimate; Temp. FluctuationsHotHot Extremes5-10 Mild2-5 ColdCold Extremes3-6 Traffic, Truck VolumesLowIntersections5-10 Thoroughfares3-6 Heavy Loads5-10 Moderate5-10 High5-10 Assumptions: Unmodified mixes designed for 20 yrs, PMA in wearing surface and basesGeneric Conventional LCCA Timeline and Revised PMA Timelines Based on Study Results PMA in Surface (2-4 ) -FillStruc. in Surface and -FillMill -FillPMA Benefits quantified, but does it make sense economically?

6 To evaluate the overall long-term economic efficiency between competing alternative investment optionsTraditionally used to HMA alternative versus PCC alternative Purpose of Life Cycle Cost AnalysisTimeCostThe Life CycleInitial ConstructionRehabilitationMaintenanceTim eRideQualityPerformanceCostPerformancePe riodAnalysis PeriodRemainingLifeAnalysis PeriodNet Present Value (NPV)TimeNetPresentValueInitial ConstructionRehabilitationMaintenanceSal vage0 The cost of all activities are computed at time = 0, accounting for discount rate (interest rate minus inflation rate) and time. This is called the N P of Using PMAUse LCCA to Evaluate Actual Cost or Savings of Using PMA Recognizing Its Enhanced PerformanceLCCA for PMA Compare Unmodified Alternative to PMA Alternatives Example Follows, Each Agency MustEvaluate Using Own Inputs: Prices, Performance Periods, Designs, Strategies, Discount Rate, User Costs, Etc LCCA ToolsLCCS Tools asphalt Pavement Alliance Software LCCA LCCAE xpress FHWA RealCostAssumptions for Following " HMA PavementDiscount Rate.

7 4%No User Costs ConsideredAnalysis Period = 40 (PG 64-22) $36/ton$ (PG 76-22) $41/ton$ (PG 64-22) $35/ton$ (PG 76-22) $40/ton$ (PG 64-22) $35/ton$ (PG 76-22) $40/ton$ $ Patching $36/syQuantities (per mile) Mainline: 2-lanes @ 12 ft ea. 14,080syShoulders: 1 @ 10 ft and 1 @ 4 ft 8,212syReferencesPrices from Maryland's "Pavement Selection Process"Maintenance from "Pa DOT Pub. 242, Pavement Policy Manual"Performance Scenarios are Examples from " Quantifying Effects of PMA .."(15% increase for PMA)Pre se nt Worth Ana lysis (ln/mi) for --LCC Unmodified) sectionInterest4 Year Construction Item and/or Material QuantityUn it Cos t/Unit Current Price PW0 10" HMA Base ( 3 - 10 EAL) $ $268,928$268,9280 " HMA Binder (3 - 10 EAL) $ $67,302$67,3020 2" HMA Wearing (3 - 10 EAL) $ $55,475$55,4750 10" HMA Base ( - 3 EAL) $ $156,849$156,8490 " HMA Binder ( - 3 EAL) $ $39,253$39,2530 2" HMA Wearing ( - 3 EAL) $ $32,355$32,3550 Maint.

8 & Protection of Traffic ls$14,264$14,264$14,2640 Mobilization ls$34,109$34,109$34,10910 Deep Patch 1% (mainline) $ $5,076$3,42910 Mill 2" (mainline) $ $19,712$13,317102" hma overlay (mainline) $ $55,475$37,47710 Maint. & Protection of Traffic ls1, $ $1,846$1,24710 Mobilization ls4, $ $4,414$2,982$0$018 Mill 2" $ $31,209$15,40618 Deep Patch 3% (mainline) $ $15,192$7,49918#60 scratch $ $15,192$7, " hma overlay (binder) $ $67,302$33,222182" hma overlay (wearing) $ $55,475$27,38418#60 scratch $ $8,856$4, " hma overlay (binder) $ $39,253$19,377182" hma overlay (wearing) $ $32,355$15,97118 Maint. & Protection of Traffic ls$6,091$6,091$3,00718 Mobilization ls$14,566$14,566$7,190$0$028 Same Scenario as Year 101 ls$86,524$86,524$28,854$0$034 SameScenario as Year 181 ls$285,492$285,492$75,242$0$020 Total Annual Maintenance ($1825/yr)40yr1, $ $73,000$33,316$0$0 TotalPre se nt Worth$1,005,328 Alternative 1: Unmodified - All ,$NPW,$0 10 Binder2 Wearing102 mill/fill 87K58K1% patching(not on shoulders)182 mill285K141K3% Binder2 Wearing(incl.)

9 Shoulders)28 Same as as 285K75 KAnnualMaint ($ )73K33 KTotal NPW: 1,005 KPre se nt Worth Ana lysis (ln/mi) for --LCC Modified Surface) sectionInterest4 Year Construction Item and/or Material QuantityUn it Cos t/Unit Current Price PW0 10" HMA Base ( 3 - 10 EAL) $ $268,928$268,9280 " HMA Binder (3 - 10 EAL) $ $67,302$67,3020 2" HMA Wearing (3 - 10 EAL) $ $63,078$63,0780 10" HMA Base ( - 3 EAL) $ $156,849$156,8490 " HMA Binder ( - 3 EAL) $ $39,253$39,2530 2" HMA Wearing ( - 3 EAL) $ $36,790$36,7900 Maint. & Protection of Traffic ls$14,541$14,541$14,5410 Mobilization ls$34,771$34,771$34,771$0$018 Mill 2" $ $31,209$15,40618 Deep Patch 3% (mainline) $ $15,192$7,49918#60 scratch $ $15,192$7, " hma overlay (binder) $ $67,302$33,222182" hma overlay (wearing) $ $63,078$31,13718#60 scratch $ $8,856$4, " hma overlay (binder) $ $39,253$19,377182" hma overlay (wearing) $ $36,790$18,16018 Maint.

10 & Protection of Traffic ls$6,368$6,368$3,14318 Mobilization ls$15,228$15,228$7,517$0$034 SameScenario as Year 181 ls$298,469$298,469$78,662$0$020 Total Annual Maintenance ($1825/yr)40yr1, $ $73,000$33,316$0$0 TotalPre se nt Worth$940,824 Alternative 2: Modify Wearing Course (top 2 , including shoulders) ,$NPW,$0 10 Binder2 Wearing182 mill298K147K3% Binder2 Wearing(incl. shoulders)34 Same as 298K79 KAnnualMaint ($ )73K33 KTotal NPW:941 KPre se nt Worth Ana lysis (ln/mi) for --LCC Modified Surface & 4"Base) sectionInterest4 Year Construction Item and/or Material QuantityUn it Cos t/Unit Current Price PW0 4" HMA Modified Base ( 3 - 10 EAL) $ $123,341$123,3410 6" HMA Base ( 3 - 10 EAL) $ $161,357$161,3570 " HMA Binder (3 - 10 EAL) $ $67,302$67,3020 2" HMA Wearing (3 - 10 EAL) $ $63,078$63,0780 4" HMA Base ( - 3 EAL) $ $71,937$71,9370 6" HMA Base ( 3 - 10 EAL) $ $94,110$94,1100 " HMA Binder ( - 3 EAL) $ $39,253$39,2530 2" HMA Wearing ( - 3 EAL) $ $36,790$36,7900 Maint.