The Birmingham age-herald. [volume] (Birmingham, Ala.) 1902-1950, 1910-06-19
The Construction of
Sand-Clay Roads
Bv B. E Pool, Civil Engineer and Road Expert,
Birmingham Ala

PERHAPS no type OF ROAD Is So ihuS"
in the public eye today as the SAND
olav road. 1t has undoubtedly proven
a success in many instances ana as
a road of comfort to man and BEAST
Its elastic surface has no superior II
ia less injurious to automobiles thah
other roads, and in the matter OF en-
nense is less expensive in hrst Cost
and less for repairs. me sanu-
clay road may be constructed WIN
less crown than macadam, and THIS
feature aids in the distribution and
comfort of travel.
while the sand-clay road has IN
many instances proven a success, yet
there are some notable cases OF fall-
ure. But by failure more Valuaoie
Lrovledge is often obtained than py
success.
EVERY true student of natural law
must understand the exception TO the
rule. as well as the reason for the eA-
,an+ion Ordinary sand and cay
make better road than all clay or
all sand because they have the ten
dency to overcome the bad quaii'ies
IN each other The sand renders the
CLAW less sticky and clay overcomes the
LIQUID character of sand. From this
observation it might be concluded
that any haphazard mixing of SAND
and clay would produce sand-cias
road. but no greater mistake could
be made than to assume good re-
suits would invariably follow when
the proportions used and the prln-
eipals undertaking the mixing Is not
clearly understood by the road build
or. 1t is manifested that a certain
definite proportion must exist De
tween the sand and clay in order that
fhe greatest naturalization of the pad
qualities in the clay and sand may De
obtained. and the resulting composi-
ton product the best road. 1t is evil
dent that deficiency of clay would
leave the sand predominating and the
resulting road excessively sandy. Like
wise a deficiency of sand would leave
the clay with tout support ready for
rain and travel to produce a muddy
road. Since this definite proportion
is so vitality essential to the success
full construction of a sand-clay road,
we will attempt to outline the only
known method of producing 1t prac-
tically.
The thoughtful reader has already
caught the intimation that the grains
of sand in a proper mixture must be
in contact with only the yoids between
the grains of sand filled with clay.
Manifestly the amount of clay must
necessarily vary according to the char
acter of sand. coarse sand requirin z
more clay than fine sand. But in all
cases the grains of sand must be in
contact in order to give rigidity to tn e
travel surface when the clay becomes
softened by rain. Furthermore this
contact relation must have sufficient
depth TO support the loads to be hauled
over it. To effect this contact re-
lation the sand and clay is brought to-
gether on the road in such proportion!
as may seem to be necessary and In
italy mixed with pillow or harrow eth
er in a dry or wet state as circum
stances may permit.
To assume that this alone constitute
the construction of sand-clay road il
q most serious mistake indeed the pro
cess is only begun and not until everl
lamp of clay the size of a pea is re
duced to paste by the addition of wate
can sand be combined with it In the con
tact relation above described It is evi
dent, therefore, that the road must b,
exceedingly muddy from top to bottom
end from side to side before unfornit,
OF mixture is possible. This is a mos
critical period in the construction an,
the stoutest hearted road builder ofte'
loses hope and courage and feels tina
he has made an utter failure, when IL
should know and the public should knoy
that this Is his opportune time to effec
and really is effecting the contact mix
ture. He should. moreover, know whe
there is an excess of clay and NOR
sand needed when the road is in thi
sloppy condition. This knowledge can b
acquired only by observation and ex
perience and successfully applied by close
ly watching the manifestations.
Clearly. then. 1t Is easy to understan
how often failure occurs. Tn only rar
cases do we find the composition pei
fectly mixed in a natural state. Conss
quently the mixture must be obtained b
artificial means through the puddlin
process and this requires time. Usual
one or two years Is necessary for II
accomplishment and not infrequently tn
read becomes we'll nigh impossible dul
ing this pudding period.
The most casual observer will mott,