What is asphalt? - ✔✔generally a by-product of petroleum distillation; a complex hydrocarbon; soluble
in petroleum products; can be naturally-occuring
What is tar? - ✔✔generally a by-product of coal production; resista
...
What is asphalt? - ✔✔generally a by-product of petroleum distillation; a complex hydrocarbon; soluble
in petroleum products; can be naturally-occuring
What is tar? - ✔✔generally a by-product of coal production; resistant to petroleum products
How can a source of asphalt be identified? - ✔✔by solubility tests
Where was asphalt obtained from originally? - ✔✔Island of Trinidad and Venezuela; lakes
What are petroleum-based asphalts? - ✔✔a waste product from refinery-processing of crude oil;
"bottom of the barrel"; properties depend on refinery operations and composition depends on crude
source
What are the three bituminous material types? - ✔✔1. asphalt cement/hot mix asphalt
2. emulsified asphalt
3. cutback asphalt
What are emulsified asphalts composed of? - ✔✔asphalt cement, water, and an emulsifying agent
What are cutback asphalts composed of? - ✔✔asphalt cement with petroleum solventWhat are the basic steps of refinery operation? - ✔✔1. pumping
2. storage
3. heating
4. distillation
5. condensing and cooling
6. separation
What are the three components of asphalt? - ✔✔asphaltenes, resins, and oils
What do emulsifiers do? - ✔✔give surface charge to asphalt droplets suspended in water medium;
anionic (limestone compatible) or cationic (siliceous gravel compatible); allow for bitumen to be mixed
at lower temperatures; cheaper, safer, and better for the environment compared to cutbacks.
What are three cutbacks? - ✔✔1. Rapid Cure (RC); high volatility of solvent; tack coats and surface
treatments
2. Medium Cure (MC); moderate volatility; stockpile patching mix
3. Slow Cure (SC); low volatility; prime coat and dust control
good for fast projects, but not used because it's harmful for the environment
What were the early specification for lake asphalts and for petroleum asphalts? - ✔✔lake asphalts:
-appearance
-solubility in carbon disulfide
petroleum asphalts:
-consistencyWhat is consistency? - ✔✔the way a liquid holds together; stiffness; softness or hardness
What specifications for petroleum asphalts developed? - ✔✔1. penetration grade (scale of hardest to
softest)
2. viscosity-graded specifications (scale of softest to hardest)
3. superpave binder specification
What is viscosity? - ✔✔the ratio between the applied shear stress and the rate of shear strain
Why is viscosity an important test to perform on asphalt? - ✔✔a relationship between temperature and
viscosity can be determined, and there exist ranges of compaction and mixing
What does superpave stand for? - ✔✔superior performing pavement
What is asphalt binder selection dependent on in superpave specifications? - ✔✔performance (rutting,
fatigue cracking, low temperature cracking)
What is the basic superpave specification? - ✔✔performance grade (PG), which is based on physical
properties
What affects the superpave specification? How does it affect it? - ✔✔climate; the first number is the
average 7-day maximum pavement temperature, and the second number is the minimum pavement
temperatureWhat criteria must be considered when selecting an asphalt binder? - ✔✔1. geographic area
2. air temperature
3. pavement temperature
4. loading type
5. reliability
What were superpave specifications developed from? - ✔✔air temperatures
How does testing for performance grade work? - ✔✔test the same type of asphalt for multiple
temperatures until the sample fails to meet the specification requirement; the asphalt belongs to the
grade based on the last temperature that passed the specification
What are the four performance grade binder tests? What do they help simulate? - ✔✔1. Rotational
Viscometer (RV); temperature-viscosity relationship
2. Direct Shear Rheometer (DSR); rutting & fatigue cracking
3. Bending Beam Rheometer (BBR); low-temperature cracking
4. Direct Tension Tester (DTT); low-temperature cracking
What is aging as it relates to asphalt? - ✔✔asphalt is a petroleum product and oxidizes and hardens over
time
What are two binder aging methods? - ✔✔1. Rolling Thin Film Oven (RTFO); simulates manufacture and
construction aging2. Pressure Aging Vessel (PAV); simulates long-term pavement aging
What is RAP? - ✔✔reclaimed asphalt pavement (RAP) is recycled asphalt pavement; superpave
transition was difficult due to grading difficulties and mixing difficulties, but partial blending occurs to a
significant extent; may have to adjust the performance grade.
see https://engineering.purdue.edu/NCSC/library/video.htm
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