Chp 9 Asphalt

Question 1

Where is asphalt sourced from?

Answer 1

It is sourced from Petroluem

Question 2

What are the types of Asphalt?

Answer 2

there are 3 types of ASPHALT:
- asphalt cement
- asphalt cutback
- asphalt concrete

Question 3

What is asphalt cutback?

Answer 3

It is produced by dissolving asphalt cement in hydrocarbon solvent. It is used to be sprayed on pavement so that the solvenet evaporates leaving behind the asphalt binder.

Question 4

What is asphalt emulsion?

Answer 4

it is asphalt cement dissolved in water. It has the same applciations has asphat cutback. When the emulsion is added to the aggregates on the pavement, the water evaporates allwoing the asphalt globs to come together forming a binder.

Question 5

What are the advantages of Asphalt?

Answer 5

• adheres to most aggregate
• Waterproof
• durable
• resistant to reaction with mild most acids and alkalis.

Question 6

What are the types of asphalt faluires?

Answer 6

3 types:
- Rutting
happens at high temperature. It is the deformation under the wheels due to high temperature.

• thermal cracking
  happens at low temperature.
• Fatigue
  it is measured in the intermeidate temperature.

Question 7

When can liquid asphalt be used?

Answer 7

It can be used to seal cracks in pavement.
It can be used to make small roads.

Question 8

What are the chemical properties of asphalt you should know about?

Answer 8

• it is a hydrocarbon which means it is mostly made of carbon and hydrgen in additon to sulfur and oxygen and Nitrogen.
• its most important property is viscoisty. Its viscoisty chnages with temperature. It increases with low temperature and decreases at high temp.

Question 9

What are the type of asphalt design?

Answer 9

There are 3 types of asphalt design:
- Hveem (obselute)
- Superpave
- Marshall

Question 10

What are the advanatges of superpave design?

Answer 10

• It increases the service life of the road
• It Reduces the lifecycle costs
• It reduces the mainatnce cost
  -it can resist failures better.

Question 11

What type of material is asphalt?

Answer 11

Asphalt is a Visco-elastsic material.
Elastic at High Temps, like a fluid.
Viscous at Low Temps, like a solid.

Question 12

What are the types of aging conditions?

Answer 12

• Unaged: When the asphalt is still in the tank.
• Construction: When it is being used in construction.
• Long term:

Question 13

What is aging and what causes it?

Answer 13

Aging refers to the increaes in the viscosity of asphalt physical hardening.

It happens due to the oxidation of the asphalt and volatilaizations.

Question 14

List design features that make superpave better than Marshall.

Answer 14

• The cylinder samples in Superpave are bigger which allows for bigger coare aggregate to be used which is more economical.
• The load is considerd to be be inclined which is what it is actualy.
  Marshall design cosniders the laod apploed to be vertical.

Question 15

List all the tests

Answer 15

• Rolling Thin Film:
  Used to stimulate short term aging.
• Pressure aging vessel:
  used to stimulate long term aging for 20 years ahead.
• Flash Point:
  Measures the minum tempertaure with sufficent vapors to flash when exposed to flame.

Rational Viscometer:
Measure the viscoity and the ability to pump binder at the asphalt plant.

Dynmaic Shear Rhemoeter:
Tests complex shear modilus of binders. used for measuring rutting and fatigue.

• Bending beam rheometer:
  Tests low temp stifness and thermal cracking.
  measures the midpoint deflection of a simoly supported beam.