The Secret Life of an Asphalt Plant

Toni CarrollDirector of QualityGraniterockOctober 26, 2016

History

• 1st Mechanical Mixers in Paris is 1854

• 1st facility opened in US in 1870

• 1st facility similar to today built in 1901 in Massachusetts

Photo: Cummer HMA Plant: 1917

Source: (State Archives of Florida)

History

• Drum Plants appeared in 1910

• Retrofitted Portland Cement Concrete mixers

Photo: Drum plant in 1950s

Source: http://www.dufferinconstruction.com/about-us/history/history-timeline/

Modern Day Asphalt Plants

BATCH PLANT DRUM PLANT

Graniterock South San Francisco HMA Batch Plant

Graniterock Redwood City HMA Drum Plant

Differences in HMA Plants

BATCH PLANT DRUM PLANTRaw

aggregates Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Raw aggregatesFed into

drying/mixing drum at

appropriate %

Dried in first part of drum

Asphalt binder added near

middle of drum

Aggregates & asphalt binder

mixed as it moves through

drum

Deposited in truck or silo

*Flows shown are for typical virgin mix

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Photo of the Lake Herman Batch Plant curtesy of Syar Industries

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Batch Plant Walk ThroughRaw

Aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Batch Plant Walk ThroughRaw

Aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Sample

PointSource: Chris Yarnell presentation on Batch Plant HMA Production

Batch Plant Walk ThroughRaw

Aggregates

Dryer

Screened into 4

sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Source: http://www.morerap.us/resources/reports.html

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Source: http://www.nilangasphalt.com/asphalt-batch-mix-plant.html

Batch Plant Walk ThroughRaw

aggregates

Dryer

Screened into 4 sizes

Batched into pugmill with binder for

mixing

Mixed in pugmill

Deposited in truck or silo

Source:http://highwaymaterials.com/facilities/wrightsville/wrightsville.html

Drum Plant Walk ThroughRaw

Aggregates

Aggs proportioned to mix

design

Aggs dried

Asphalt binder added

Aggs & binder mixed

Deposited in truck or

silo

Drum Plant Walk ThroughRaw

Aggregates

Aggs proportioned to mix

design

Aggs dried

Asphalt binder added

Aggs & binder mixed

Deposited in truck or

silo

Drum Plant Walk Through

Raw Aggregates

Aggs proportioned to mix

design

Aggs dried

Asphalt binder added

Aggs & binder mixed

Deposited in truck or

silo

Drum Plant Walk Through

PARALLEL FLOW COUNTER FLOW

Source: https://www.fhwa.dot.gov/pavement/recycling/98042/06.cfm

Drum Plant Walk Through

Source: http://www.solidswiki.com/images/d/d7/

Raw aggregates

Aggs proportioned to mix

design

Aggs dried

Asphalt binder added

Aggs & binder mixed

Deposited in truck or

silo

Environmental Measures

Recycling! Track out prevention systems Spray bars & water trucks Baghouses Blue smoke system Warm Mix Asphalt

Baghouses

Blue Smoke Control System

Warm Mix Asphalt

Source: http://marylandpaving.com/productsmain/warm-mix-asphalt/

Summary

Batch & Drum plants are very different Both have pros & cons when compared

to each other Both can produce high quality hot mix

asphalt Both are stewards of the environment

Clarify the type of plant you are using

Ask for a tour!

Questions?