TR 331 - Highway Materials - Part II

Natural asphalt occurs naturally in deposits, like the Trinidad lake, while petroleum asphalt is made through the industrial distillation of crude oil.

Tar can be derived from bituminous coal or petroleum. Tar from coal is obtained through destructive distillation, while tar from petroleum is produced by chemical treatment (cracking).

Bitumen's key physical properties include its adhesive properties (cementitious), which bind aggregates together, and its viscous nature, which allows it to be readily mixed and spread.

<p>The challenge lies in creating tests that accurately characterize the asphalt binder's behavior throughout its lifespan in the mix, considering its changes during mixing, laying and while in service.</p> Signup and view all the answers

<p>Petroleum asphalt has a very high boiling point of $525^\circ C$ (977 F), indicating it is the heaviest fraction of crude oil and contains complex hydrocarbons with strong intermolecular forces.</p> Signup and view all the answers

<p>Asphalt's stiffness and consistency change with temperature, and thus, its performance in pavement applications is affected by temperature variations.</p> Signup and view all the answers

<p>High asphalt deformations and flow contribute to rutting, while excessive bleeding is associated with a less viscous asphalt binder.</p> Signup and view all the answers

<p>The penetration test assumes that asphalt binders with similar penetration values will deform similarly in real-world conditions. However, this assumption may not always hold true in practice.</p> Signup and view all the answers

<p>Different penetration grades cater to various traffic and temperature conditions. Factors like traffic volume, temperature extremes, and expected stresses influence the selection of an appropriate penetration grade.</p> Signup and view all the answers

<p>The softening point test determines the temperature at which asphalt transitions from a solid-like state to a more fluid state. This temperature is crucial for understanding the binder's resistance to deformation under heat.</p> Signup and view all the answers

<p>Viscosity is a fundamental property of fluids, measuring their resistance to flow at a given temperature. In contrast, penetration and softening point are empirical tests that indicate the consistency of asphalt based on specific conditions.</p> Signup and view all the answers

<p>Comparing asphalt binders at a common reference temperature allows for a consistent assessment of their rheological properties, as their consistency varies with temperature.</p> Signup and view all the answers

<p>The rheological properties of asphalt govern the pavement's ability to withstand stresses and deformations caused by traffic and temperature fluctuations. These properties directly influence the pavement's durability and overall performance.</p> Signup and view all the answers

<p>The formula is Retained penetration = (Penetration of aged sample / Penetration of original sample) * 100%.</p> Signup and view all the answers

<p>The Flash Point is the lowest temperature at which vapors from heated asphalt ignite upon exposure to an open flame, indicating a critical safety threshold.</p> Signup and view all the answers

<p>Temperature susceptibility refers to how the consistency of asphalt changes with temperature, measured by parameters such as penetration and viscosity.</p> Signup and view all the answers

<p>PI is determined by plotting log(Pen) against temperature (T), where the slope of the resulting straight line is A, indicating temperature susceptibility.</p> Signup and view all the answers

<p>The Cleveland Open Cup test and the Pensky Martin Flash Point test are used to measure these safety parameters.</p> Signup and view all the answers

<p>Absolute viscosity is the viscosity of asphalt measured at 60°C.</p> Signup and view all the answers

<p>Kinematic viscosity is the absolute viscosity divided by density and is measured at 135°C.</p> Signup and view all the answers

<p>Absolute viscosity is calculated using the formula μ = τ/γ, where μ is viscosity, τ is shear stress, and γ is the rate of shear.</p> Signup and view all the answers

<p>The TFO Test determines the effect of heat and air on a thin film of bituminous material.</p> Signup and view all the answers

<p>The Ductility Test involves stretching an asphalt briquette under water at 25°C until it breaks, measuring the distance at rupture in cm.</p> Signup and view all the answers

<p>Short-term aging occurs during the mixing process, while long-term aging happens after pavement construction due to environmental exposure.</p> Signup and view all the answers

<p>Kinematic viscosity corresponds to the viscosity of asphalt during mixing and laydown conditions.</p> Signup and view all the answers

<p>The TFO Test measures changes in penetration, viscosity, and ductility expressed as a percentage of the original values.</p> Signup and view all the answers

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Materials that contain bitumen, resembling it or being sources of it.

A solid or semi-solid material, black and viscous, mainly made of hydrocarbons from petroleum.

A viscous black liquid with adhesive properties, derived from coal or wood through destructive distillation.

Asphalt occurring naturally in deposits like native asphalt or rock asphalt.

Refinery asphalts created from the fractional distillation of crude oil, the heaviest and highest boiling point fraction.

The ratio of the penetration of an aged sample to that of the original sample, expressed as a percentage.

The ratio of the viscosity of an aged sample to that of the original sample, expressed as a percentage.

The lowest temperature at which vapors from heated asphalt ignite with an open flame.

The lowest temperature at which asphalt burns continuously without the addition of heat.

A measure of temperature susceptibility of asphalt based on the slope of log(penetration) vs temperature.

The study of deformation and flow of matter, important for understanding asphalt properties.

A material whose stiffness varies with temperature, like asphalt.

A test measuring the hardness or fluidity of asphalt by the depth a needle penetrates.

Classification of asphalt by its penetration depth, indicating its hardness.

The temperature at which asphalt begins to flow, indicated by a steel ball sinking.

A measure of a fluid's resistance to flow at a specific temperature.

Cracking due to repeated stress and strain on asphalt, often from high stiffness.

The shape changes in Hot Mix Asphalt related to its rheological properties.

Viscosity of asphalt measured at 60°C using a vacuum viscometer.

Calculated as absolute viscosity divided by density, measured at 135°C.

Instruments used for measuring viscosity; includes Brookfield and DSR.

Measures how far asphalt can stretch before breaking, under water at 25°C.

Aging of asphalt during the mixing process affecting its properties.

Assesses heat and air's effects on a thin asphalt film at 163°C for 5 hours.

Aging of asphalt due to environmental exposure and loading after construction.

A test that simulates long-term aging in a controlled environment, part of Superpave.