 | Parkways and park roads |  |
BITUMINOUS PAVEMENTS:
Bituminous pavements (asphalt) are cheaper to build than concrete
pavements; they are more costly to maintain over the long
haul (time period) but are easier to repair. The riding surface
is smoother because expansion joints are not needed. However,
chuckholes develop with freezing and thawing action. The black
surface resists ice formation but it is vulnerable to damage from
gasoline.
The advantages of concrete versus asphalt can be argued by
people who know more about it than I do...but I like the Colonial,
and the Suitland, and the Baltimore-Washington Parkways because
it's my prejudicial nature.
The Asphalt Institute defines Asphalt as, "A dark brown to
black cementious material solid, semisolid, or liquid in consistency,
in which the predominating constituents are bitumens which occur in
nature as such or which are obtained as residue in refining
"petroleum." (ASTM Designation D8)
The Asphalt Institute defines Bitumen as, "A mixture of hydrocarbons
of natural or pyrogenous origin, or a combination of both;
frequently accompanied by nonmetallic deriviatives which may be
gaseous, liquid, semisolid, or solid; and which are completely
soluble in carbon disulfide."
The key words indicate that asphalt may contain bitumen, and
that bitumen is a mixture of hydrocarbons. Asphalt, then, is that
black semisoft material mined in Venezuela which we use to mix with
oil to make a road.
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