Materials Final Exam

Front 1

Define viscosity

Back 1

the ratio between the applied shear stress & the rate of shear

Front 2

What are 4 desired properties of aggregates used in asphalt?

Back 2

toughness, soundness, deleterious materials, gradation

Front 3

What are the 3 gradations and what are each of their properties?

Back 3

Uniformly Graded: poor interlock, high perm.

Well Graded: good interlock, low perm.

Gap Graded: good interlock, low perm.

Front 4

What is the "Nominal Maximum" and what is "Maximum" when referring to aggregates used for asphalt?

Back 4

Nominal Max: one size larger than the first seive to retain more than 10%

Maximum: one size larger than the nominal max size

Front 5

How is performance grading symbolized? Explain each component.

Back 5

PG 64 - 22

"Performance Grade"

Average 7-day max pavement temp.

Minimum pavement temp.

Front 6

What is Pavement Temperature a function of?

Back 6

Air temperature, Depth, Latitude

Front 7

What is FATIGUE CRACKING?

Back 7

A series of interconnected cracks caused by failure due to repeated loading.

Front 8

What were some early asphalt specifications and how have they advanced?

Back 8

Appearance, Consistency (chewing, penetration machine);

Advancement: Viscosity specifications

Front 9

How does asphalt differ from tar?

Back 9

Asphalt is a derivative of petroleum products while tar generally comes from coke (coal) production. Tar is resistant to petroleum products while asphalt is soluble in them.

Front 10

What are the 3 types of asphalt?

Back 10

Asphalt cements, cutbacks, emulsions

Front 11

What are the 3 categories of cutbacks? briefly describe each.

Back 11

1. Rapid Cure (RC): high volatility, used for tack coats

2. Medium Cure (MC): moderate volatility, used for stockpile patching mix

3. Slow Cure (SC): low volatility, used for prime coats, dust control.

(environmental regulations are increasingly limiting the use of these products)

Front 12

Briefly describe emulsions

Back 12

Mixture of asphalt cement, water, and emulsifying agent. Emulsifier gives surface charge to asphalt droplets suspended in water medium.

2 Types:
-ANIONIC(Negative): limestone

-CATIONIC(Positive): silica gravels

Front 13

What are the 2 components of asphalt?

Back 13

Asphaltenes (high viscosity component) & Maltenes (resins)

Front 14

What are the 3 types of innovative mix designs/systems?

Back 14

1. Perpetual Pavement

2. Stone Matrix Asphalt

3. Open Graded Friction Course

Front 15

Describe Perpetual Pavement.

Back 15

Combines the smoothness & safety advantages of asphalt with an advanced multi-layering paving process that extends the life of the roadway to half a century of more.

Layers:
-HMA Base layer (resists fatigue cracking)

-Intermediate layer (res. rutting)

-Wearing surface (res top-down cracking, rutting)

Front 16

Describe Stone Matrix Asphalt.

Back 16

Has a one size coarse aggregate gradation. High asphalt binder & high mineral filler content.

-Rut resistant and durable

-One major drawback is high cost.

Front 17

Describe Open Graded Friction Course.

Back 17

Designed to have a large number of air voids so that water can drain through, and over, its surface.

-Reduces the amount of splash/spray & glare from headlights during rain.

-Noise reduction.

Front 18

Briefly describe Mortar and what it is used for.

Back 18

A construction material formed by combining masonry units such as stone and brick with binding materials.

-bonds units together

-serves as a seating material

-provides strength to the wall

-provides aesthetic qualities

Front 19

What are 2 types of mortar?

Back 19

1. Lime mortar (lime, sand, water)

- hardens slowly, but has high workability and water retention.

2. Portland Cement (cement, sand, water)

-poor workability & water retention, but hardens quickly and has high compressive strength & durability.

Front 20

What are 5 types of masonry units?

Back 20

1. Concrete masonry units

2. Clay Brick

3. Structural Clay Tiles

4. Glass Block

5. Stone

Front 21

What distinguishes hollow masonry units from solid units? Give an example of each.

Back 21

Hollow: net CS area < 75% gross CS area.

-concrete blocks.

Solid: net CS area > 75% gross CS area.

-clay bricks.

Front 22

What are some properties of concrete masonry units?

Back 22

-made of aggregate & cement

-zero slump

-molded under pressure

-steam cured

Front 23

What are the weight classes of concrete units?

Back 23

-Lightweight (easier handling & transportation, higher thermal resistance)

-Medium weight

-Normal weight

Front 24

What are the two types of load bearing units for concrete?

Back 24

Type I: Moisture controlled

Type II: Non-Moisture controlled

Front 25

Durability is a function of _____________.

Back 25

Absorption.

Front 26

Shrinkage is a function of _______________.

Back 26

Moisture content.