The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1901-08-08


useful and disable products of the
earth's crust.
Time, weather. climate and soil seem
to have no effect upon asphaltum. On
the island of Trinidad, in the British
west Indies, are Lodges of asphaltum
which project into the ocean. They
have been there, apparently, for cen
lures salt water breakers and waves
have pounded and hammered them for
years, yet their sharp, we'll defined
edges prove that the pummeling and
pounding which have worn away the
most Obdurate Of rocks have failed to
even round the edges Of the asphaltum
lodges.
About twenty-five years ago govern
ment engineers decided to pave Penn
SyiVanta avenue in Washington with
ASPHALT. That was the beginning of
the general use of the scientific mys-
terry To- street pavements. Today over
"a 100000 square feet of street pave
ment in the United States and Cana
da are covered with asphalt. This as
phalt paving would make a boulevard
JWenCy-siX feet wide over $50 miles
long and would reach from New York
TO New Orleans. and then have several
miles to spare for side streets.
Spread out in one sheet the q, 900 900
square miles Of asphalt paving which
has been paid in over $50 cities in
North America would blanket eight
and one-eighth square miles, and yet
the road builders say that this country
has only just begun the use of asphalt
for street pavement. They cite the fact
that in all Europe there are only 3,000,-
600 square miles of asphalt streets, or
but 100000 square yards more than are
laid in this country every year.
Most Of the asphaltum used for street
paving n America comes from one of
the most interesting of natural curiosi-
ties, Pitch lake. in the island of Trini-
dad. This lake is verftable Dot of
asphaltum- It's area is only 113 acres.
II has been the great source of supply
for years. Hundreds Of thousands of
tons OF the material have been taken
from II, but like the Widows cruise of
oil, it never can be emptied. 1t is a
schiller. No matter how much is
taken out, the excavation is refIled in
a few weeks.
The lake is about a mile from the
docks, and the crude asphaltum is cut
and dug, out Of the crust and hauled
IN mule carts. mule cars or buckets,
which are carried on an overhead ca
bic way to the vessels, where it is
dumped into the hold.
Inc asphaltum crust is strong
enough to support a mule and cart. al
the mule would sink if he stood still
i ne temperature of the asphaltum is
slightly above the normal temperature
or the atmosphere. At some time in
the long forgotten past Pitch lake
boiled over and the liquid asphaItum
spread over the island and ran into the
sea. It was then that the lodges. which
bear testimony 10 the lasting and wear
ing qualities of the material were
formed.
Crude asphaltum cannot be used for
paving streets. It must be refined, and
the process is carried on in stills and
retorts, Tor slow heat, agitation and
precipitation make thx rude material
Mt Tor paving purposes The refined
product is put in barrels and shipped
to the yards Of the paving companies,
Where II is mixed and otherwise pre-
pared for the street The crude as
phaltum is placed in tanks, where it is
melted down to facilitate the mixing
OF the other materials which enter into
the paving composition, and to rid il
of its impurities. JETS 81 compressed
air are shot through the LIQUID mass
while it is in the tank, so as TO stir it
up, Tor constant agitation OF the ma
terial is necessary in the preparatory
stages Of the process.
Some Of the asphaltum may melt at
Q lower temperature, a certain proper
crude petroleum is poured into the as
phaltum. This is done because the oils
IN asphaltum are volatile. and it is
necessary to save these oils. When
the -huxing" and mixing process is
completed the mixture is called paw
ing cement
To make the cement a street mix
ture," clean, sharp sand. which has
been heated In huge revolving drums
is mixed with it. The sand is conveyed
by an elevator to a storage bin which
STANDS over an asphalt mixer" The
sand falls into a measuring box and q
lever releases just the right amount
and dumps it into the mixing machine.
A certain proportion of carbonate Of
lime is also added. and the mass is
taken to a mechanical mixer. where the
asphalt cement sand and carbonate Of
lime are thoroughly mixed with each
other The material now is called
street mixture and is dumped into
carts and taken to the streets to be
paved.
Volney W. Foster. the pathfinder of
the north shore, and one Of the original
asphalt men in the west, used to argue
in those days when asphalt pavements
were regarded as an experiment:
Every time a wagon passes over a
road something has got to give way
the wagon or the street. If one or the
other isn't polite something breaks. II
the wagon refuses to give way the
street pavement must. Asphalt is the
Only material laid in a street which has
the traits of a gentleman; it gives way
without breaking, and is the better for
it."
Eugene r. Cox. another asphalt man,
put it this way
A f1rst-class street pavement should
b a firm cushion: the foundation
should give the firmness, the surface
the cushion. Asphalt is the only ma
teFial known to man which viii give
this combination, and unless an as
phalt pavement has a good foundation,
and unless the good foundation mas
good cushion, the combination for
perfect street is not present. Inat IS
why we asphalt roadmakers put so
much thought and attention ~ our
street foundations.
When asphalt pavements were nrst
introduced the foundation consisted OF