Plantmix Asphalt Industry of Kentucky Winter Meeting February 10, 2011

Transcription

1 Plantmix Asphalt Industry of Kentucky Winter Meeting February 10, 2011

2 AASHTO Guidelines for Geometric Design of Very Low-Volume Local Roads (2001) ADT 400 AASHTO Guide for Design of Pavement Structures (1993) ESALs < 1,000,000 Rule of Thumb ADT < 1,000

3 Adaptations of Heavy Duty Pavement Design Methodologies PAIKY Interactive Pavement Design Guide AASHTO 1993 Kentucky Transportation Cabinet Asphalt Pavement Alliance PerRoads Express 1

4 Development of PAIKY Interactive Pavement Design Guide Asphalt Pavement Alliance PerRoads Express 1 Example Designs Mixture Specifications

5 PAIKY Website:

6 Development Interactive Pavement Thickness Design Guide for Use with PAIKY Website Update 2001 PAIKY Asphalt Pavement Design Guide for: Catalog based on AASHTO 1993 Procedures Aggregate and Asphalt Catalog Full Depth Asphalt Catalog Catalog based on KYTC Design Memo 6A-99 33% Asphalt Design Curves

7 Key Features Traffic Subgrade Design Catalogs Example Designs

8 Low Volume Traffic Estimated Average Daily Traffic (ADT) Range: 100 to 24,000 ADT ITE Trip Generation Factors Estimated ESALS Range: 7,500 to 8,000,000 ESALs Range of Subgrade Strength CBR 1 to 11 Design Catalogs AASHTO 1993 Asphalt and Aggregate Full Depth Asphalt KYTC Design Memo 6A-99, Asphalt and Aggregate

9 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition Single Family Detached Housing Residential Condominium/Townhouses General Office Buildings Shopping Center Supermarket

10 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition Single Family Detached Housing

11 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition Residential Condominium/Townhouses

12 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition General Office Buildings

13 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition Shopping Center

14 User Defined, or Estimated Using ITE Trip Generation Manual 7 th Edition Supermarket

15 Distribution of Cars, Trucks, and Vehicle Loadings 98% Cars, 2% Single Unit Trucks 92% Cars, 5% Single Unit Trucks, 3% Combination Unit Trucks Range of ESALs 7,500 to 8,000,000 ESALS Light Traffic Loadings Assumed AASHTO 1993 Load Equivalency Factors Automobiles: Single Unit Truck: Combination Unit Truck: ESALs per vehicle 0.45 ESALs per vehicle 0.90 ESALs per vehicle

16 Range of CBR Values CBR 1 to 3 Highly Compressible Fine Grained Soils Liquid Limit Greater Than 50 CBR 4 to 5 Low Compressible Fine Grained Soils Liquid Limit Less Than 50 CBR 6 to 8 Coarse Grained Soils, Sand, Sandy Soil, Gravely Soils, Gravel CBR 9 to 11 Rock (limestone, sandstone, durable shale, select granular materials)

17 AASHTO 93 Relationship M r =1500*(CBR) MEPDG Relationship M r =2555*(CBR) 0.64 AASHTO Soil Classification

18 AASHTO % Reliability 2.0 Maximum Change in Serviceability Index Variations: Two Catalogs Aggregate and Asphalt Full Depth Asphalt KYTC Design Memo 6A-99 Design ESALS CBR

19 Minimum Designs 1.25 AC Surface 2.5 AC Base 6.0 Aggregate Base

20 Minimum Designs 1.25 AC Surface 4.25 AC Base

21 Minimum Designs 1.25 AC Surface 2.5 AC Base 4.0 Aggregate Base

22 Functional Classification Urban Connectors Rural Connectors Parking Lots and Streets Two-Way Average Daily Traffic Percentage Trucks Subgrade Strength Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness Calculate Thickness of HMA

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26 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 5.5

27 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 4

28 Functional Classification -- Parking Lots and Streets Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% 91,366 ESALs Subgrade Strength 10,400 psi Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 8.25

29 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 4

30 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 3.75

31 Functional Classification -- Parking Lots and Streets Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% 22,841 ESALs Subgrade Strength 10,400 psi Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 7

32 Two-Way Average Daily Traffic 3000 ADT Percentage Trucks 8% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 7.25

33 Two-Way Average Daily Traffic 3000 ADT Percentage Trucks 8% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 4.5

34 Functional Classification -- Parking Lots and Streets Two-Way Average Daily Traffic 3,000 ADT Percentage Trucks 8% 391,572 ESALs Subgrade Strength 10,400 psi Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 9.75

35 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% CBR 2 Aggregate Base Thickness 8 Thickness of HMA 8.75

36 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% CBR 2 Aggregate Base Thickness 6 Thickness of HMA 6.25

37 Functional Classification -- Parking Lots and Streets Two-Way Average Daily Traffic 700 ADT Percentage Trucks 8% 91,366 ESALs Subgrade Strength Soil A-7-6 Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 8

38 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% CBR 2 Aggregate Base Thickness 6 Thickness of HMA 7.25

39 Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% CBR 9 Aggregate Base Thickness 6 Thickness of HMA 5.25

40 Functional Classification -- Parking Lots and Streets Two-Way Average Daily Traffic 700 ADT Percentage Trucks 2% 22,841 ESALs Subgrade Strength Soil A-7-6 Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 7

41 Two-Way Average Daily Traffic 3000 ADT Percentage Trucks 8% CBR 2 Aggregate Base Thickness 8 Thickness of HMA 10.75

42 Two-Way Average Daily Traffic 3000 ADT Percentage Trucks 8% CBR 2 Aggregate Base Thickness 6 Thickness of HMA 7.75

43 Functional Classification Parking Lots and Streets Two-Way Average Daily Traffic 3,000 ADT Percentage Trucks 8% 391,572 ESALs Subgrade Strength Soil A-7-6 Soil Classification Soil Modulus of Elasticity (10,000 to 30,000 psi) Aggregate Base Thickness 6 Thickness of HMA 9.5

44 Calculate ADT

45 Calculate ADT Type of Building(s) Single Family Detached Housing Residential Condominium/Townhouse General Office Building Shopping Center Supermarket

46 Select Number of Units & Calculate

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48 ADT 700 8% T CBR 9 ADT 700 2% T CBR 9 ADT % T CBR 9 KY 6A-99 AASHTO 93 PerRoad Asphalt Aggregate Asphalt Aggregate Asphalt Aggregate ADT 700 8% T CBR 2 ADT 700 2% T CBR 2 ADT % T CBR 2 KY 6A-99 AASHTO 93 PerRoad Asphalt Aggregate Asphalt Aggregate Asphalt Aggregate

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50 Mixture Type Selection Knowing the lingo Superpave Versus Marshall Understanding the components and ingredients in an asphalt mixture Superpave designations Superpave mix design Typical Applications

51 Typical Design Recommendations x-inches of aggregate base (DGA) x-inches of base x-inches of binder x-inches of surface

52 Since Superpave was implemented in 2000, specifying asphalt mixtures has become increasingly complicated It isn t just base, binder, and surface anymore There are literally dozens of material options resulting in hundreds of possible mixture designations

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54 When specifying asphalt mixes Traffic (or Class) based on ESALs Generic description (position within the pavement structure) Nominal Maximum Aggregate Size Polish Resistance Aggregate requirement Performance Graded Liquid Asphalt Binder Grade Other variations?

55 Prior to 2000, the KYTC Standard Specifications reference Marshall Mixtures Beginning with the 2000 Standard Specifications, all asphalt references relate to Superpave Superpave is great for high volume roadways (interstates and parkways) but may not be the best mix for parking lots

56 Superpave mixtures are coarse and boney rely on stone-to-stone contact Very little natural sand is allowed Superpave surfaces appear more like binder mixes of the past Permeability (interconnected air voids) is a concern with Superpave Not very workable and difficult to rake into tight areas

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58 Marshall mixtures utilize more natural and and/or dust than Superpave Resulted in a tighter or pretty mix desired for parking lots and driveways Sufficient for the vast majority of commercial, residential, and light industrial applications

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60 Contractors who do not perform KYTC work may be using Marshall mixes Contractors who do a lot of KYTC work typically will produce Superpave mixtures Some contractors will produce mix for commercial customers in a different silo using a Superpave mix but adding in some dust or natural sand Allow for slightly lower VMA than KYTC specs

61 Reference the latest revision of the KYTC Standard Specifications? If so, you are specifying Superpave Is this really what you want for commercial or light industrial applications? May want to look at more dust or fines for tighter mix. Reference Asphalt Institute MS-2 for Marshall Mixtures

62 Require that all contractors be prequalified by KYTC The Division of Contract Procurement maintains a list of qualified contractors on their website Require the use of KYTC approved materials (aggregates, etc.) The Division of Materials maintains a listing of qualified sources on their website

63 Specify Mixture Design Method upfront -- Superpave or Marshall Necessary for level playing field for bidding -- bid apples to apples Select testing and specifications to match the requirements don t mix and match

64 PAIKY Example Specification allows for both Marshall Mixtures and modified Superpave mixtures for private and commercial projects

65 Visit the Kentucky Transportation Cabinet Website Inside the Cabinet Division of Materials Asphalt Mixtures Warrants for Selecting Asphalt Mixtures and Compaction Options

66 Recycled (or reclaimed) Asphalt Pavement ( RAP) Mixtures utilizing RAP produce excellent results and should not be discouraged Results in a more rut-resistant mixture because the agehardened asphalt binder in the rap stiffens the mixture Don t expect big savings on unit bid costs due to handling & crushing

67 CL2 ASPH SURF 0.38D PG CL 2 ASPH BIND 0.50D PG CL 2 ASPH BASE 0.75D PG 64-22

68 ESAL Class 1 No longer in use by KYTC (roads less than 300,000 ESALs) ESAL Class 2 Less than 3 million ESALs ESAL Class 3 Between 3 and 30 million ESALs ESAL Class 4 Over 30 million ESALs

69 ASPH BASE = Base mixture in lower pavement layers (not permanently exposed to traffic) ASPH BIND = Intermediate layer between base and surface mixtures ASPH SURF = Surface mixture designed as the final riding surface

70 Aggregates mined in local quarries are crushed and screened into various sizes for use in products like hot mix asphalt

71 Surface Mixtures 0.38 primarily used on Class 2 mixes 0.50 primarily used for Class 3 & 4 with very heavy truck traffic Binder Mixtures Typically 0.5 mixture Base Mixtures 0.75 typical for parking lots, etc. 1.0 and 1.5 for higher volume roadways

72 Superpave recommends at least 3 times the maximum aggregate size in order to achieve compaction Place 1.5 mixes between Place 1.0 mixes between Place.75 mixes between Place 0.5 mixes between Place.38 mixes between Lift thickness of 1 should not be held to minimum compaction requirements

73 Interstates and Parkways (ADT > 5,000) and all roads with ADT with ADT > 15,000 = Type A Type A aggregates include dolomites and slags and will not round off or polish under traffic (rock quarries have certain materials and ledges classified as non polishing) Parkways with <5,000 ADT and other roads between 5,000 and 15,000 ADT = Type B Allows blending of different coarse aggregates and/or more fine aggregate Less than 5,000 ADT = Type D All approved aggregates (limestone, etc.)

74 Liquid asphalt is made in a refinery from crude petroleum It is a strong cement Waterproof and readily adhesive Bottom of the barrel of crude oil Barrel of Crude Oil Gasoline Kerosene Lt. Gas Oil Diesel Motor Oils Asphalt

75 Fluid at high temperatures for paving In the summer months, must be stiff enough to prevent rutting In colder climates, must resist low-temperature cracking Asphalt

76 147.2 F -7.6 F PG Performance Grade Average 7-day max pavement temperature Minimum pavement temperature

77 High traffic high stress applications Base Grade (low-moderate traffic) Use PG on all Interstates, Parkways, and facilities with more than 30 million ESALs

78 PG should only be used in high stress applications where heavy truck traffic is expected Consider using in intersections to minimize potential for rutting Current cost spread between PG and is about $8-$9 more per mix ton

79 Select the aggregates based on local availability that can meet the specification requirements Determine the PG Grade necessary for the project based on the anticipated traffic

80 What do I need?

81 50-blow Marshall or Class 2 mixtures will be sufficient for most commercial applications Surface Mix = 0.38 Binder Mix = 0.5 (if needed) Base Mix = 0.75 Select Type D aggregates PG should be used unless unusual loading conditions exist

82 KYTC website Warrants for Selecting Asphalt Mixtures and Compaction Options

83 Discuss mixes with local paving contractors and/or the contractor that will perform the work Contractors know what their plants and crews do best you will get a better final product if you solicit input and see what mixtures they are most comfortable placing

84 Know the lingo Develop good and consistent specifications Know what mixture works best in which application Combine mixtures for efficiency Solicit input from local paving contractors

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