ASPHALT BINDERS AND ASPHALT MIXTURES - Materials for Civil and Construction Engineers - page 326

T ABLE 9.1 Paving Applications of Asphalt

Term Description Application

Hot mix asphalt Carefully designed mixture of asphalt Pavement surface, patching

and aggregates

Cold mix Mixture of aggregates and liquid Patching, low volume road

asphalt surface, asphalt stabilized

base

Fog seal Spray of diluted asphalt emulsion on Seal existing pavement

existing pavement surface surface

Prime coat Spray coat to bond aggregate base Construction of flexible

and asphalt concrete surface pavement

Tack coat Spray coat between lifts of asphalt Construction of new

concrete pavements or between an

existing pavement and an
overlay

Chip seal Spray coat of asphalt emulsion Maintenance of existing

(or asphalt cement or cutback) pavement or low volume road

followed with aggregate layer surfaces

Slurry seal Mixture of emulsion, well-graded Resurface low volume roads

fine aggregate and water

Microsurfacing Mixture of polymer modified Texturing, sealing, crack

emulsion, well-graded crushed filling, rut filling, and minor

fine aggregate, mineral filler, leveling

water, and additives

9.3 Temperature Susceptibility of Asphalt

The consistency of asphalt is greatly affected by temperature. Asphalt gets
hard and brittle at low temperatures and soft at high temperatures. Figure 9.7
shows a conceptual relation between temperature and logarithm of viscosi-
ty. The viscosity of the asphalt decreases when the temperature increases.
Asphalt's temperature susceptibility can be represented by the slope of the
line shown in Figure 9.7. The steeper the slope the higher the temperature
susceptibility of the asphalt. However, additives can be used to reduce this
susceptibility.
When asphalt is mixed with aggregates, the mixture will perform
properly only if the asphalt viscosity is within an optimum range. If the vis-
cosity of asphalt is higher than the optimum range, the mixture will be too