Bitumen and Asphalt Mixes

Question 1

What are Cutbacks?

Answer 1

Asphalt cement cut with petroleum solvents.

Question 2

What is Emulsion?

Answer 2

Mix of asphalt cement, water, and emulsifying agents.

Question 3

What is the process of Rapid Curing (Cutbacks)?

Answer 3

Dissolving hard residue in highly volatile solvents (gasoline or naphtha)

Question 4

What is the use of Rapid Curing (Cutbacks)?

Answer 4

Tack coats or surface treatments.

Question 5

What is the process of Medium Curing (Cutbacks)?

Answer 5

Dissolving medium residue in less volatile solvents (kerosene)

Question 6

What is the use of Medium Curing (Cutbacks)?

Answer 6

Stockpile patching mix and prime coat.

Question 7

What is the process of Slow Curing (Cutbacks)?

Answer 7

Diluting soft residue in nonvolatile/low volatile fuel oil or by stopping refining process before all fuel is removed from stock.

Question 8

What is the use of Slow Curing (Cutbacks)?

Answer 8

Prime coat, stock piling and road mixing.

Question 9

What is the process of Emulsion?

Answer 9

Surface charge to asphalt droplets suspended in water medium. Both anionic and cationic.

Question 10

What is anionic?

Answer 10

Negative
Alkaline
Good with limestone (+charge)

Question 11

What is cationic?

Answer 11

Positive
Acid
Good with silica gravels (-charge)

Question 12

What does emulsion do?

Answer 12

Sets viscosity of emulsions and hardness of asphalt cement.

Question 13

What is Slow Setting for (Emulsion)?

Answer 13

Tack coats, fog seals.

Dense graded cold mixes.

Question 14

What is Medium Setting for (Emulsion)?

Answer 14

Open graded cold asphalt agg mixtures.

Question 15

What is Fast Setting for (Emulsion)?

Answer 15

Surface treatments.

Question 16

What do higher grades (Cutbacks) mean in terms of viscosity?

Answer 16

Higher viscosity.

Question 17

What is curing the Cutback?

Answer 17

Evaporating the solvent from the asphalt residue.

Question 18

What are 7 different problems with asphalt pavements?

Answer 18

1) Fatigue
2) Thermal Cracks
3) Transverse Cracks
4) Shoring
5) Pothole and Ravelling
6) Bleeding
7) Rutting

Question 19

What does Bitumen consistency testing involve?

Answer 19

Penetration
Viscosity
Ductility

Question 20

What does Bitumen durability testing involve?

Answer 20

Short term ageing

Long term ageing

Question 21

What does Bitumen safety testing involve?

Answer 21

Flash point clevland open cup

Question 22

What does Bitumen purity testing involve?

Answer 22

Solubility test

Question 23

What does consistency describe?

Answer 23

Fluidity or plasticity of bitumen.

Question 24

What is penetration testing?

Answer 24

Penetrating a needle into substance with specific load, temperature and time.

Question 25

What are the advantages of the penetration test?

Answer 25

Fast Precision established Grades asphalt Temp susceptibility can be determined

Question 26

What are the disadvantages of the penetration test?

Answer 26

Empirical test | Does not reflect differences in asphalt.

Question 27

What are the grades of the penetration test (5)?

Answer 27

``` 40-50 60-70 80-100 130-150 180-200 ```

Question 28

What climates are soft (low viscosity) asphalts used in?

Answer 28

Cold climates to avoid thermal cracking.

Question 29

What climates are hard (high viscosity) asphalts used in?

Answer 29

Hot climates to avoid rutting.

Question 30

How is short term binder ageing tested?

Answer 30

Using a rolling thin film oven | - Simulates ageing from hot mixing and construction.

Question 31

How is long term binder ageing tested?

Answer 31

In a pressure ageing vessel. - 7 to 10 years simulation. - 50 grams for 20 hours - Pressure of 2070 kPa - At a temp of either 90, 100 or 110.

Question 32

Advantages of viscosity testing?

Answer 32

Fundamental property Based on max pave surface temp Test method precision established Temperature susceptibility is controlled

Question 33

Disadvantages of viscosity testing?

Answer 33

Not applicable to non-newtonian materials | Wide range of properties for the same grade

Question 34

What is viscosity in physical terms?

Answer 34

It is the ratio between applied shear stress and the rate of shear.

Question 35

How is viscosity tested?

Answer 35

Using viscosity tubes of rotational viscometers.

Question 36

List the Viscosity grading based on the viscosity of the original asphalt (AC).

Answer 36

``` AC-2.5 AC-5 AC-10 AC-20 AC-30 AC-40 ```

Question 37

List the Viscosity grading based on the viscosity of the asphalt residue (AR). This is from rolling film oven testing.

Answer 37

``` AR-1000 AR-2000 AR-4000 AR-8000 AR-16000 This is at 60 degrees ```

Question 38

How does the ductility test work?

Answer 38

- By measuring the distance that a standard briquette of asphalt cement will stretch before breaking. - Done at temp of 25 degrees (achieved by water bath) - Two ends separated at 5cm/min - Salt added to water to prevent sample from floating in water bath.

Question 39

How does the softening point test work?

Answer 39

- Measures temperature at which bitumen will flow under own weight. - Bitumen poured in two copper rings on a copper plate and cooled - Put into water bath of 4 degrees, leave for 15mins - Apply temp at 5 degrees/min. - Bit will soften as temp increases.

Question 40

What is the solubility test for?

Answer 40

Measuring purity of bitumen and quantify amount of impurities.

Question 41

How pure is refined bitumen?

Answer 41

Usually more than 99.5%.

Question 42

What is temperature susceptibility of bitumen?

Answer 42

Rate of which the consistency of bitumen changes with change in temperature.

Question 43

How is the penetration index determined?

Answer 43

Measuring penetration at two different temperatures an drawing log (pen) versus temperature. Slope is susceptibility. (rise over run in calculation)

Question 44

What does higher penetration index mean in terms of temperature susceptibility?

Answer 44

Higher penetration index means lower susceptibility. | Vice versa.

Question 45

How is the viscosity temperature susceptibility (VTS) defined?

Answer 45

The slope of the log log (viscosity at 135 degrees) and the log (temperature in K)

Question 46

What does higher temperature susceptibility mean in regards to VTS?

Answer 46

Higher temperature susceptibility means higher VTS.