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Asphalt MixturesBy: Braden Watson
Introduction
What my company does.
My experience with asphalt
My goals
History of asphalt
Asphalt occurs naturally in both lakes and in rock asphalt.
History of Asphalt
First recorded as a road building material around 625 BC in Babylon.
Comes from the Greek word “asphaltos” meaning secure.
Used by the Greeks and the Romans.
Sir Walter Raleigh
First Asphalt Roadways
Turnpikes in Scotland
Asphalt comes to AmericaMainly used for sidewalks and crosswalks.
Roads started to be paved in the late 1860s
Edmund J. DeSmedt laid the first asphalt road.
Paving in America
In 1896, New York City adopted asphalt paving.
New York required a 15 year warranty.
Original Patents
The first patent on Hot Mix Asphalt (HMA) was in 1871 by Nathan B. Abbott of Brooklyn, New York.
Limited Technological growth.
Original patents expired in 1920.
Changing Techniques
Until 1900 almost all asphalt came form Trinidad Lake.
Refined Petroleum AsphaltsOriginally used as an additive.
Paving Operations
My Project
I created an asphalt mix design for Asphalt Materials.
I worked with Asphalt Materials Inc. (Producer)
Star Paving (Contractor)
CMT Engineering (Designer/Quality Control)
My Project
Time:Design time: 50 hours
Quality Control: 20+ hours
Materials used:Sinclair 64-22 binder
AMI Aggregates
CMT’s asphalt laboratory
Marshall Mix Design
6 basic steps:Aggregate selection
Asphalt binder selection
Sample Preparation
Stability determination
Density and Voids
Optimum asphalt binder calculations
Aggregate Selection
Determine aggregate physical properties:Toughness and abrasion
Durability and soundness
Cleanliness
Shape and surface texture
Gradation and size
Aggregate Blending
Must meet the specification for the job.
Typical specifications require a certain percentage be retained on a particular sieve size by weight.
Asphalt Binder Evaluation
The Marshall mix design does not have a specific asphalt binder.
Each entity has its own specification for binder usage:
UDOT 58-22
UDOT 58-28
APWA 64-22 (Also same as UDOT)
Optimum Asphalt Binder Content
This is specified in the mix design specifications by UDOT, APWA, or other city entities.
Sample Preparation
Several trial aggregate-asphalt binder blends are created.
Usually 5 different blends, 3 samples of each
Samples are prepared in 0.5 percent by weight increments.
Marshall Compaction
Automatic and manual versions
Specified number of blows.
Specifications for the machine.
Stability and Flow
Performance prediction measure.
Measures the maximum load.
Measure the specimens plastic flow as a result of the loading.
Density and Voids
Bulk specific gravityFinds the maximum density of the asphalt.
The specific gravity is used to calculate the Air Voids and the Voids in the Mineral Aggregate.
This is what you don’t want!
Stability: Recommended Oil Content:Flow: Virgin Oil Content:Air Voids: Lottman (TSR):VMA Oil Supplier/Grade:Anti-Strip: Bulk Unit Weight:
Max. Density (Rice): No. of Blows:
(inch) (mm)1 25
3/4" 191/2" 12.53/8" 9.5#4 4.75#8 2.36#16 1.18#30 0.6#50 0.3#100 0.15#200 0.075
33 28-4253
24
3-77.012
11-2318
60-8076
100
None 143.4
Job Mix Formula
88.4
Specification
94
100100100
100100
75
5.294900
RECOMMENDED DESIGN CRITERIA6.14
144.0
Sinclair PG 64-22
Percent Passing
15.2
2.389
Conclusion
I have learned the basics of asphalt mix designs.
My design was used on a couple of projects:
Wal-Mart on 10400 South and Bangerter Hwy.
2 Walgreens
I have developed good relationships with everyone involved.
Good technical understanding of asphalt.
Questions?