Asphalt Flashcards
What is asphalt concrete?
a viscous cimentitious material primarily composed of bitumen or high molecular weight hydrocarbons mixed with mineral aggregates
why do we say asphalt is not sustainable?
It is a byproduct of the treatment of crude oil.
What is Rheology and what factor mostly affects the properties?
Rheology is the study of deformation ad flow of the asphalt under stress or strain. Temperature is the biggest factor, where asphalt starts getting viscous around 60C. Pressure and loading conditions are also factors that can affect the Rheological properties
what kinds of tests are most common (name and describe them)
Flash Point Test: Determine the temperature to which an asphalt can safely be heated without the risk of propagating fire (if asphalt is at high enough temperatures it will emmit a flammable vapor). You put an open flame near asphalt and heat it to find the flash point temperature of asphalt.
Ductility test: Asphalt getting stretched until failure under standardized conditions. High ductility = high temp susceptibility, low ductility= poor adhesive properties
How does factors influence stiffness, and how do they affect it?
High temperatures and long loading conditions make the asphalt behave plastically, while low temperatures and short loading conditions make it behave elastically. In the middle of these two extremes asphalt is viscoelastic
What is temperature susceptibility?
it is to measure the degree at which the asphalt’s properties change with respect to temperature
what makes good asphalt?
-low temperature susceptibility
-good adhesion and cohesion
-good durability - low rate of hardnening
-proper viscosity for high and low service temperature (to avoid rutting and shrinkage)
what are the two types of liquid asphalts, in what conditions is it best to use them and why?
cutback asphalt is produced with a petroleum solvent that eventually evaporates, leaving a solid asphalt binder. It is most commonly used in higher temperatures, in remote locations or for patching small areas
Emulsifying asphalt:
