Asphalt CEMENT

Question 1

Since when Asphalt have been used?

Answer 1

since 3500 BC

Question 2

What is asphalt cement?

Answer 2

Viscous cementitious material composed primarily of high molecular weight hydrocarbons.

Question 3

What is asphalt concrete?

Answer 3

asphalt cement of asphalt cement, mineral agg., and possibly some admx.

Question 4

Asphalt cement is a bituminous material. Bitumen occurs ___?

Answer 4

Naturally: as rock asphalt and lake asphalt
Industrially: leftover when lighter constituents of crude oil are distilled away during refining.

Question 5

What are the main properties of asphalt cement?

Answer 5

• Waterproof
• ability to adhere to agg.
• viscoelastic material that depending on T can be either solid or liquid

Question 6

What are the 3 methods to go from solid asphalt cement to liquid asphalt cement? (control time frame of liquid asphalt)

Answer 6

1. Melting
2. Dissolving
3. Emulsifying

Question 7

Describe the melting process of asphalt cement

Answer 7

heating above 140°C (if lower than 140, asphalt cement becomes solid)

Question 8

Describe the dissolving process of asphalt cement

Answer 8

Controlling setting time with type of petroleum solvent. (this process is called cutting back). Hardening occurs as the solvent evaporate.

Question 9

Describe the Emulsifying process of asphalt cement

Answer 9

Dispersing the asphalt cement in water. Asphalt and water don’t mix but emulsifying agents such as soaps, fine clay make them mixable (this mix results –> fluid=emulsified asphalt). After, water evaporates and asphalt particles recombine.

Question 10

How do we differentiate asphalt?

Answer 10

with their physical & rheological properties

Question 11

what are the composition of asphalt cements?

Answer 11

In general; 80-87% carbon, 9-11% H, 2-8% O, 0-1% Nitrogen (azote)

Question 12

What are the 3 components of asphalt cement and their contribution to it?

Answer 12

1. Oil (viscosity and fluidity)
2. Asphaltene (Strength and stifness)
3. Resin (Adhesion and ductility)

Question 13

The oil acts as a solvent for the ____.

Answer 13

The oil acts as a solvent for the resin. (oil dissolve resins)

Question 14

The ___ acts as a solvent for the asphaltenes.

Answer 14

The resin acts as a solvent for the asphaltenes. (resin dessolve asphaltenes)

Question 15

How can the temperature decrease the viscosity of the asphalt cement?

Answer 15

By increasing the T, asphaltenes become more soluble in resins, which in turn become more soluble in the oils. Then the material becomes less viscous.

Question 16

How can the temperature increase the viscosity of the asphalt cement?

Answer 16

By decreasing T, asphaltene becomes less soluble, form micelles, and the material becomes more viscous.

Question 17

What is the glass transition temperature ?

Answer 17

Tg= 140°C; separates the solid and liquid transition of asphalt cement

Question 18

asphalt is a thermo____ material. +definition of the word

Answer 18

Thermoplastic (very sensitive to T)

Question 19

When do you have a newtonian fluid?

Answer 19

when T>140 °C (liquid–> Flexible)

Question 20

When do you have a visco-elastic solid?

Answer 20

When T<140°C (the structure is effectively frozen and the material becomes rigid and brittle)

Question 21

What is the age hardening phenomenon?

Answer 21

Asphalt cement hardens and becomes less ductile (Volatilization of lightweight carbon and oxidization by reacting with oxygen)

Question 22

What are 2 artificial aging method to evaluate changes due to aging in asphalt cement?

Answer 22

1. ASTM D-2872 (rolling thin film oven [RTFO])
2. AASHTO provisional standard PP1: previously aged in RTFO is exposed to high P and T.

Question 23

How did Asphalt cement have been traditionnaly graded?

Answer 23

Penetration
Viscosity
Performance grading

Question 24

What is the PEN test?

Answer 24

Needle at T=25deg C

Question 25

In the PEN test, if the gauge read 290, what is the penetration?

Answer 25

PEN=29mm

Question 26

the higher the penetration #(PEN grade–>gauge reading), the _____.

Answer 26

the higher the penetration #, the lower the viscosity.

Question 27

What is the viscosity grade?

Answer 27

AC–> viscosity asphalt cement
AR–> Viscosity on aged residue

Question 28

the higher the number of poises, the higher ____.

Answer 28

the higher the number of poises, the higher the viscosity.

Question 29

What is the PG?

Answer 29

Performance grading is penetration/viscosity grading with properties and conditions of the asphalt cement

Question 30

what does PG XX YY represent?

Answer 30

XX= 7 days maximum pavement T, 52 to 70 deg C
YY= minimum expected pavement temperature, -16 to -40 deg C

Question 31

PG 64-16

Answer 31

7 days max pavement T during summer is 64deg C and minimum pavement T during winter is -16deg C

Question 32

What are the 3 things that asphalt cement stiffness depend on?

Answer 32

Temperature
Loading rate
Loading duration

Question 33

Low temperature and/or short duration behavior?

Answer 33

Elastic behviour

Question 34

High temperature and/or long duration behaviour?

Answer 34

Viscous behaviour; Approaches a viscous Newtonian fluid % stiffness approaches (S) 3*viscosity/time of aging

Question 35

Low temperature and/or short duration behaviour?

Answer 35

Elastic behaviour (S=E)

Question 36

Intermediate loading time behavior?

Answer 36

elastic + viscous, stiffness decreases nonlinearly