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Asphalt.report

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Mao Perez
Mao Perez

The document discusses the temperature susceptibility of asphalt and how it affects the viscosity and performance of asphalt mixtures. It states that asphalt viscosity is highly dependent on temperature, with viscosity decreasing as temperature increases. It also explains that the asphalt cement grade used in a mixture needs to have a viscosity that falls within the optimal range for the temperature conditions of the area, with softer grades used in colder climates and harder grades used in hotter climates. The document also provides details on the chemical composition and molecular structure of asphalt.

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Asphalt.report
?The consistency of asphalt is greatly affected by temperature. Asphalt gets hard and brittle at low temperatures and soft at high temperatures.
? Figure shows a conceptual relation between temperature and logarithm of viscosity. ? The viscosity of the asphalt decreases when the temperature increases. Asphalts temperature susceptibility can be represented by the slope of the line. ? The steeper the slope the higher the temperature susceptibility of the asphalt.
` ? When asphalt is mixed with aggregates, the mixture will perform properly only if the asphalt viscosity is within an optimum range. ? Asphalt viscosity optimum range = mixture will be too brittle and susceptible to low temperature cracking ? Asphalt viscosity optimum range = the mixture will flow readily, resulting in permanent deformation ? due to temperature susceptibility, the grade of the asphalt cement should be selected according to the climate of the area
? The viscosity of the asphalt cement should be mostly within the optimum range for the area¨s annual temperature range ? Soft-grade asphalt=cold climates ? Hard-grade asphalts=hot climates
Chemical Properties of Asphalt ? Mixture of a wide variety of hydrocarbons consisting of hydrogen and carbon atoms Minor components: - sulfur, nitrogen, oxygen and trace metals ? The molecular structure of asphalt affects the physical and aging properties of asphalt, as well as how the asphalt molecules interact with each other and with aggregate.
? Asphalt molecules three arrangements: ? A. Aliphatic or parraffinic- form straight or branched chains ? B. Saturated Rings- have the highest hydrogen to carbon ratio ? C. Unsaturated rings- aromatic
Asphalt cement consists of.. Asphaltenes Maltenes ? Dark brown friable solids that are chemically complex ? Responsible for the viscosity and the adhesive property of the asphalt. ? >10% ? Consists of resins and oils ? Dark and semi solid or solid with a viscosity that is largely affected by temperature ? Resins act as agents to disperse asphaltenes in the oils; the oils are clear or white liquids
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Asphalt.report

  • 2. ?The consistency of asphalt is greatly affected by temperature. Asphalt gets hard and brittle at low temperatures and soft at high temperatures.
  • 3. ? Figure shows a conceptual relation between temperature and logarithm of viscosity. ? The viscosity of the asphalt decreases when the temperature increases. Asphalts temperature susceptibility can be represented by the slope of the line. ? The steeper the slope the higher the temperature susceptibility of the asphalt.
  • 4. ` ? When asphalt is mixed with aggregates, the mixture will perform properly only if the asphalt viscosity is within an optimum range. ? Asphalt viscosity optimum range = mixture will be too brittle and susceptible to low temperature cracking ? Asphalt viscosity optimum range = the mixture will flow readily, resulting in permanent deformation ? due to temperature susceptibility, the grade of the asphalt cement should be selected according to the climate of the area
  • 5. ? The viscosity of the asphalt cement should be mostly within the optimum range for the area¨s annual temperature range ? Soft-grade asphalt=cold climates ? Hard-grade asphalts=hot climates
  • 6. Chemical Properties of Asphalt ? Mixture of a wide variety of hydrocarbons consisting of hydrogen and carbon atoms Minor components: - sulfur, nitrogen, oxygen and trace metals ? The molecular structure of asphalt affects the physical and aging properties of asphalt, as well as how the asphalt molecules interact with each other and with aggregate.
  • 7. ? Asphalt molecules three arrangements: ? A. Aliphatic or parraffinic- form straight or branched chains ? B. Saturated Rings- have the highest hydrogen to carbon ratio ? C. Unsaturated rings- aromatic
  • 8. Asphalt cement consists of.. Asphaltenes Maltenes ? Dark brown friable solids that are chemically complex ? Responsible for the viscosity and the adhesive property of the asphalt. ? >10% ? Consists of resins and oils ? Dark and semi solid or solid with a viscosity that is largely affected by temperature ? Resins act as agents to disperse asphaltenes in the oils; the oils are clear or white liquids