Construction Materials – Asphalt UPDATED ACTUAL Exam
Questions and CORRECT Answers
what are liquid asphalt-cutbacks - produced by dissolving asphalt cement in a lighter molecular
weight hydrocarbon solvent
advantage of liquid asphalt-cutbacks - applied easily in the field without heating
disadvantages of liquid asphalt-cutbacks - -not cost effective
- hazardous materials due to the volatility of the solvents
- releasing environmentally unacceptable hydrocarbons into the atmosphere
what are liquid asphalt-emulsion? - produced by dispersing the asphalt in water using an
emulsifying agent
why is the use of emulsion increasing? - no hazardous or costly solvents
fog seal for preserving existing pavement - used to enrich oxidized asphalt surface or to seal very
small cracks and surface voids
micro-surfacing - used as a protective or rehabilitative maintenance technique for paved surface
of thin asphalt surface treatment
chip seal - uses multiple surface treatments
levels below a paved road (from surface to deepest) - 1. surface course
2. base course
3. subbase course (optional)
, 4. subgrade (existing soil)
four uses for compaction - - prevent further compaction
- provides shear strength or resistance to rutting
- ensures the mixture is waterproof
- prevents excessive oxidation of the asphalt binder
warm mix asphalt - - reduce production temperatures 30-100F
why use warm mic asphalt? - reduces the viscosity (thickness) of the asphalt binder so that the
asphalt aggregates can be coated at lower temps
what does reducing the viscosity do for the mixture? - makes the mixture easier to manipulate
and compact at the lower temperature
advantages to WMA - -energy saving
- decreased emissions
- decreased fumes
- decreased binder ageing
- extended paving season
what is viscosity - resistance to flow of a liquid or gas
coefficient of dynamic viscosity is defined as what? - the shear force per unit area (shear stress)
required to drag one layer of fluid with unit velocity past another layer of unit distance away
what does high viscosity mean - liquid doesnt flow easily
Questions and CORRECT Answers
what are liquid asphalt-cutbacks - produced by dissolving asphalt cement in a lighter molecular
weight hydrocarbon solvent
advantage of liquid asphalt-cutbacks - applied easily in the field without heating
disadvantages of liquid asphalt-cutbacks - -not cost effective
- hazardous materials due to the volatility of the solvents
- releasing environmentally unacceptable hydrocarbons into the atmosphere
what are liquid asphalt-emulsion? - produced by dispersing the asphalt in water using an
emulsifying agent
why is the use of emulsion increasing? - no hazardous or costly solvents
fog seal for preserving existing pavement - used to enrich oxidized asphalt surface or to seal very
small cracks and surface voids
micro-surfacing - used as a protective or rehabilitative maintenance technique for paved surface
of thin asphalt surface treatment
chip seal - uses multiple surface treatments
levels below a paved road (from surface to deepest) - 1. surface course
2. base course
3. subbase course (optional)
, 4. subgrade (existing soil)
four uses for compaction - - prevent further compaction
- provides shear strength or resistance to rutting
- ensures the mixture is waterproof
- prevents excessive oxidation of the asphalt binder
warm mix asphalt - - reduce production temperatures 30-100F
why use warm mic asphalt? - reduces the viscosity (thickness) of the asphalt binder so that the
asphalt aggregates can be coated at lower temps
what does reducing the viscosity do for the mixture? - makes the mixture easier to manipulate
and compact at the lower temperature
advantages to WMA - -energy saving
- decreased emissions
- decreased fumes
- decreased binder ageing
- extended paving season
what is viscosity - resistance to flow of a liquid or gas
coefficient of dynamic viscosity is defined as what? - the shear force per unit area (shear stress)
required to drag one layer of fluid with unit velocity past another layer of unit distance away
what does high viscosity mean - liquid doesnt flow easily
