Civil Engineering Reference
In-Depth Information
Optimum
viscosity
range
FIGURE 9.7
Typical relation between as-
phalt viscosity and temperature.
Log temperature, Degrees Rankine
FIGURE 9.8
Thermal cracking resulting from the use of too stiff asphalt in a
cold climate area.
brittle and susceptible to low-temperature cracking (Figure 9.8). On the
other hand, if the viscosity is below the optimum range, the mixture will
flow readily, resulting in permanent deformation (rutting) as shown in
Figure 9.9.
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
should be mostly within the optimum range for the area's annual temperature
range; soft-grade asphalts are used for cold climates and hard-grade asphalts
for hot climates (See Figure 9.10).
Search WWH ::
Custom Search