Lecture 32

Question 1

What’s the basic purpose of A HMA Plant

Answer 1

To produce a quality hot asphalt mixture that contains the desired proportions of asphalt and aggregate and meets all specifications.

Question 2

What’s a Batch Plant

Answer 2

Produces asphalt in discrete batches.

Question 3

What’s a Drum Mixer

Answer 3

Continuously produces asphalt mixtures.

Question 4

What’s a Cold Aggregate Storage

Answer 4

Storage for aggregates before mixing.

Question 5

What’s a Mix Storage

Answer 5

Temporary holding area for asphalt mixtures.

Question 6

What’s an Aggregate Stockpile

Answer 6

Pile of stored aggregates for asphalt production.

Question 7

What’s Segregation

Answer 7

Separation of materials in stockpiles.

Question 8

What’s Proper Proportioning

Answer 8

Correct ratio of aggregate to binder.

Question 9

What’s a Baghouse

Answer 9

Device capturing dust from exhaust streams.

Question 10

What’s Collector Efficiency

Answer 10

Effectiveness of dust collection systems.

Question 11

Hot Mix Asphalt

Answer 11

Final product of asphalt mixing process.

Question 12

what’s a Cold Feed Bin

Answer 12

Bins for storing and feeding aggregates.

Question 13

What determines Aggregate Flow Rate

Answer 13

Belt Speed
Gate opening

Question 14

What’s an Asphalt Binder Storage

Answer 14

Tanks maintaining temperature of liquid binder, stirs to maintain consistency.

Question 15

what does RAP stand for

Answer 15

Recycled Asphalt Pavement

Question 16

Biggest thing you want to avoid during stockpiling

Answer 16

Segregation

Question 17

what’s a Pugmill

Answer 17

Equipment for mixing asphalt and aggregates.

Question 18

What’s Dust Collection Systems

Answer 18

Systems for capturing and managing dust.

Question 19

What are the common plant operations

Answer 19

1. Cold aggregate storage and feeding
2. Emission Control Systems (Dust control & collection)
3. Mix storage
4. Weighing and handling

Question 20

Asphalt Mixture production steps

Answer 20

Aggregate must be properly stockpiled to prevent
segregation, contamination, high moisture content
Aggregate and binder must be carefully proportioned
before drying and mixing
Sufficient mixing to heat, dry aggregate and obtain
uniform coating of binder
Final step in production is to temporarily store and
then transport HMA to project site without
segregation

Question 21

what are the keys to not segregate/contaminate aggregates

Answer 21

spacing/separation between each pile
minimize the handling of the aggregates
Drain and/or cover the stockpiles

Question 22

what are the basic functions of plants

Answer 22

1. Store component materials
2. Combine aggregates in proper proportions
3. Heat and dry aggregates
4. Add and mix liquid binder in proper proportions
5. Coat aggregates uniformly
6. Store mixture and load trucks without
   segregation

Question 23

what are drum-mixer functions

Answer 23

Removes moisture from
aggregate
Surface and internal
moisture
Heat aggregate to
production temperature

Question 24

what is the principal pollutant generated at drum mix and batch
facilities

Answer 24

DUST

Question 25

the three HMA facility air pollution control systems are:

Answer 25

1. Primary dry collectors; 2. Wet collectors; and, 3. Fabric filters (baghouses)

Question 26

what does a storage silo do

Answer 26

Holds mixes at proper temperatures Allows for accurate and rapid loading of trucks Multiple silos allows different mixtures to be stored and loaded out for multiple jobs

Question 27

what does proper loading of trucks help reduce

Answer 27

segregation