Marshall & Superpave Mix Design Pavement Management CourseProfessor Training Course Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Moisture Damage in Asphalt PavementsMoisture Damage in HMA Marshall & Superpave Mix DesignPhysical Properties of Aggregates 1

Objectives of Mix Design Russian Engineers Training March 2011Russian Engineers Training March 2011 Objectives of Mix Design Evaluate materials Determine aggregate proportions Determine optimum asphalt content Evaluate design mix Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 2

Aggregate Evaluation Gradation Sulfate Soundness L A abrasion Russian Engineers Training March 2011Russian Engineers Training March 2011 Aggregate Evaluation Gradation Sulfate Soundness L A abrasion Fractured faces Natural sand content Fine aggregate angularity Flat and elongated Clay particles Sand equivalency Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 3

Taking Samples and Splitting Samples Russian Engineers Training March 2011Russian Engineers Training March 2011 Taking Samples and Splitting Samples Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 4

Sample Splitters are Typically Used Russian Engineers Training March 2011Russian Engineers Training March 2011 Sample Splitters are Typically Used Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 5

Russian Engineers Training March 2011Russian Engineers Training March 2011 Types of Sampling Representative---average---several random samples added together Random---all possible sampling locations have an equal chance of being selected Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 6

Gradation / Sieve Analysis Russian Engineers Training March 2011Russian Engineers Training March 2011 Gradation / Sieve Analysis ASTM D5444 Wet vs. dry gradation Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 7

Fractured Faces ASTM D5821 Only a problem with gravels Russian Engineers Training March 2011Russian Engineers Training March 2011 Fractured Faces ASTM D5821 Only a problem with gravels Must make sure that gravel is properly crushed Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 8

Crushed Gravel Uncrushed Gravel Russian Engineers Training March 2011Russian Engineers Training March 2011 Crushed Gravel Uncrushed Gravel Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 9

Fine Aggregate Angularity Russian Engineers Training March 2011Russian Engineers Training March 2011 Fine Aggregate Angularity Used to measure angularity of fine aggregate Typically high 30’s or low 40’s for natural sand Typically mid 40’s to low 50’s for crushed fine aggregate Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 10

Most Common Aggregate Problems Russian Engineers Training March 2011Russian Engineers Training March 2011 Most Common Aggregate Problems Excessive percentage passing No. 200 sieve Excessive natural sand Inadequately crushed gravel Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 11

Three Ways to Classify Asphalt Cement Russian Engineers Training March 2011Russian Engineers Training March 2011 Three Ways to Classify Asphalt Cement Penetration Graded For example 85-100 pen Viscosity Graded For example AC-20 Performance Graded For example PG 64-22 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 12

Russian Engineers Training March 2011Russian Engineers Training March 2011 If aggregate properties and asphalt properties are ok then determine optimum asphalt content Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 13

Two Methods Generally Used to Determine Optimum Asphalt Content Russian Engineers Training March 2011Russian Engineers Training March 2011 Two Methods Generally Used to Determine Optimum Asphalt Content Marshall Superpave Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 14

Marshall Method Developed by Corps of Engineers Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall Method Developed by Corps of Engineers Simple, quick, inexpensive Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 15

Uses 4-inch diameter samples Russian Engineers Training March 2011Russian Engineers Training March 2011 Uses 4-inch diameter samples Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 16

Blend 15 to 20 aggregate samples at selected proportions Russian Engineers Training March 2011Russian Engineers Training March 2011 Blend 15 to 20 aggregate samples at selected proportions Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 17

Vary asphalt content in 0.5% increments Russian Engineers Training March 2011Russian Engineers Training March 2011 Vary asphalt content in 0.5% increments Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 18

Russian Engineers Training March 2011Russian Engineers Training March 2011 Mixing of HMA Samples Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 19

Compact samples using specified effort Russian Engineers Training March 2011Russian Engineers Training March 2011 Compact samples using specified effort Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 20

Three Types of Hammer Manual Mechanical Russian Engineers Training March 2011Russian Engineers Training March 2011 Three Types of Hammer Manual Mechanical Mechanical with slanted foot and rotating base Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 21

Russian Engineers Training March 2011Russian Engineers Training March 2011 Manual Hammer Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 22

Russian Engineers Training March 2011Russian Engineers Training March 2011 Mechanical Hammer Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 23

Marshall Hammers Manual Mechanical Slanted foot on rotating base Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall Hammers Manual Mechanical Slanted foot on rotating base On concrete slab Wood block in good condition Top plate tight on wood block Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 24

Compacting Samples & Removing From Molds Russian Engineers Training March 2011Russian Engineers Training March 2011 Compacting Samples & Removing From Molds Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 25

Russian Engineers Training March 2011Russian Engineers Training March 2011 Removing Paper Disc Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 26

Identifying Compacted Samples Russian Engineers Training March 2011Russian Engineers Training March 2011 Identifying Compacted Samples Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 27

Determining Bulk Density Russian Engineers Training March 2011Russian Engineers Training March 2011 Determining Bulk Density Obtain mass of dry compacted sample The mass of the oven dry specimen is being determined in this photograph. The next step is to place the specimen in the water bath directly below the scale (not shown) and determine its mass under water. Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 28

Weighing Sample in Water Russian Engineers Training March 2011Russian Engineers Training March 2011 Weighing Sample in Water Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 29

Blotting Sample to Determine SSD Weight Russian Engineers Training March 2011Russian Engineers Training March 2011 Blotting Sample to Determine SSD Weight Obtain mass of specimen at SSD Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 30

Bulk Specific Gravity Sometimes samples absorb lots of water Russian Engineers Training March 2011Russian Engineers Training March 2011 Bulk Specific Gravity Sometimes samples absorb lots of water Excessive absorption results in error in density measurement Excessive bubbling indicates excessive water absorption Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 31

CoreLok Specific Gravity for Porous Mixtures Russian Engineers Training March 2011Russian Engineers Training March 2011 CoreLok Specific Gravity for Porous Mixtures Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 32

Determine the Following Properties and Plot Results Russian Engineers Training March 2011Russian Engineers Training March 2011 Determine the Following Properties and Plot Results Unit Weight of Mixture Air Voids VMA Voids Filled Stability Flow Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 33

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 34

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 35

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 36

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 37

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 38

Typically select optimum asphalt content at 4 percent air voids Russian Engineers Training March 2011Russian Engineers Training March 2011 Typically select optimum asphalt content at 4 percent air voids Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 39

Russian Engineers Training March 2011Russian Engineers Training March 2011 Design Air Voids If significantly greater than 4 percent, likely to have durability problems due to low asphalt content If significantly less then 4 percent, likely to have rutting problems due to too much asphalt in mix Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 40

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 41

Russian Engineers Training March 2011Russian Engineers Training March 2011 After selecting optimum asphalt content check for stability and moisture susceptibility Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 42

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 43

Marshall Stability and Flow Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall Stability and Flow Conducted at 140 degrees F A rough measure of in-place stability and plastic flow Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 44

Moisture Susceptibility Russian Engineers Training March 2011Russian Engineers Training March 2011 Moisture Susceptibility Measured on proposed aggregate blend and asphalt content 3 Conditioned Specimens 3 Unconditioned Specimens Tensile Strength Ratio (TSR) Minimum TSR required Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 45

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 46

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 47

Russian Engineers Training March 2011Russian Engineers Training March 2011 The mix design is a starting point and will likely have to be adjusted during production Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 48

Facts About Mix Design Increase in filler results in lower AC Russian Engineers Training March 2011Russian Engineers Training March 2011 Facts About Mix Design Increase in filler results in lower AC Smaller Max agg size results in higher optimum AC content Manual hammer provides lower optimum AC content than mechanical if not calibrated Absorptive aggregate requires higher AC content Higher –200 results in higher marshall stability Reheating will significantly increase stability Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 49

Superpave is a mix design procedure and a binder classification system Russian Engineers Training March 2011Russian Engineers Training March 2011 Superpave is a mix design procedure and a binder classification system Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 50

Russian Engineers Training March 2011Russian Engineers Training March 2011 What is Superpave? Hence, there is a need for a mechanical test which can tell us whether the designed mix is resistant to rutting. It should be able to proof test the mixes and tell us whether a mix satisfies a definite criteria and passes or fails the torture test. This test should be a laboratory test method so that it can be used on designed mixes, and it should be a simple test method so that it can be used routinely by the folks who actually build our pavements. Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 51

Superpave Method Developed in 1990’s Russian Engineers Training March 2011Russian Engineers Training March 2011 Superpave Method Developed in 1990’s Involves using newly developed gyratory compactor Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 52

Superpave Gyratory Compactor Russian Engineers Training March 2011Russian Engineers Training March 2011 Superpave Gyratory Compactor ? Basis Texas equipment French operational characteristics 150 mm diameter Up to 37.5 mm nominal size Height recordation Must control pressure (600 KPa), angle (1.25 degrees), and number of gyrations (depends on traffic) ? ? Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 53

Superpave Gyratory Compactor Russian Engineers Training March 2011Russian Engineers Training March 2011 Superpave Gyratory Compactor Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 54

Placing Mold in Gyratory Compactor Russian Engineers Training March 2011Russian Engineers Training March 2011 Placing Mold in Gyratory Compactor Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 55

Uses 6-inch diameter samples Russian Engineers Training March 2011Russian Engineers Training March 2011 Uses 6-inch diameter samples Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 56

Russian Engineers Training March 2011Russian Engineers Training March 2011 Marshall & Superpave Mix Design Marshall & Superpave Mix DesignPhysical Properties of Aggregates 57

Differences Between Marshall and Superpave Size of sample: 4 inches for Marshall and 6 inches for Superpave Compactor type: Hammer for Marshall and Gyratory compactor for Superpave Compactive effort: No. of blows with hammer for Marshall and number of gyrations for Superpave Moisture Damage in Asphalt Pavements Marshall & Superpave Mix Design

Russian Engineers Training March 2011Russian Engineers Training March 2011 Any Questions??? Marshall & Superpave Mix DesignPhysical Properties of Aggregates 59