Asphalt Mixtures By: 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 America Mainly 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 Asphalts Originally 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 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 UDOT APWA (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 gravity Finds 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!

Conclusion I have learned the basics of asphalt mix designs. My design was used on a couple of projects: Wal-Mart on South and Bangerter Hwy. 2 Walgreens I have developed good relationships with everyone involved. Good technical understanding of asphalt.

Questions?