The river press. [volume] (Fort Benton, Mont.) 1880-current, 1912-06-12

:etween the larger pieces. Gravel OBJ
aimed from streams is usually inferior
10 pit gravel for the reason that the &C
lion Of the water has worn the pebbles
smooth and practically all the fine
binding material has been removed by
the anne agency. Even II clay or loan
is mixed with river or creek gravel the
result is not likely to be as satisfactory
US that obtained by the use Of pit gray
ell. Pit gravel frequently contains too
much clay or earthly matter, while river
gravel may have too much sand. In
screen the gravel SO as to eliminate the
material which is too fine or that which
Is too coarse. The screen should be
similar to that which is used in pre-
pairing material for a macadam road.
In the handling Of the gravel carr
should be exercised not to separate the
binding material from it, o should
this binding material be allowed to
settle to the bottom in spreading the
material over the road surface. 1t
will often be found advisable to spread
a thin layer of such binding material
over the surface after the material has
been distributed and rolled, and after
this the surface should be sprinkled
and rolled again or else rolled while
still damp from the rains.
A large part of the gravel found in
the Atlantic coastal plane is sufficient
~ fine and uniform to render unneces-
sary any asserting for road building
purposes, but when the gravel, espe.
cially that which is to constitute the
surface layer, contains large pebbles
these should be removed and either
thrown aside or else raked into the
foundation or recrushed. At least &C
| per cent by weight of the gravel should
be pebbles above one-eighth inch in
| size, and there should be no pebbles ii
the bottom layer that will not pass
through a two and a half or three inch
| ring, and in the top layer there should
be no pebbles which will not pass
| through q one and one-half inch ring
should be clay, and this should be uni
formly mixed and should contain nc
large Jumps. Ten or Is per cent Of clay
produces better results than 20 per cent
If the foundation or roadbed is loose
it should be carefully rolled. 1t i:
foundation for a gravel road as for
macadam road. Gravel will compac
to about 80 per zen of its depth, loos'
measure, provided earth shoulders ar
placed on both sides of the road t.
prevent the wasting away of tn
gravel on the sides. If gravel is abun
dant, however, these shoulders may b
built Of gravel instead Of with earth
or the road may be surfaced wit
gravel from shoulder to shoulder. l
the compacteu depth of the grave
road is to be eight inches and tn
width twelve feet it will take abou
$3.50 cubic yards Of gravel to the mile
and it is best to make the first laye
about six inches in depth, loose meas
ure, and the second layer about fou
inches in depth, loose measure.
Gravel should not be dumped direc
~ VII JAc lodu, uS lAAo l. uSuOA1J ~
suit in a rough, uneven surface. ]
specially devised spreading wagon
are not used the gravel should b
dumped on boards and spread frol
them on to the road.
The gravel should be placed on tn
road commencing at the end neares
the gravel pit, in order that the team
will aid in packing the material.
spike or tooth harrow may be used
, advantage in spreading the materia
but If the gravel contains only a sma
!, amount Of binding material the ha
row should not be used, as it will hay
the effect Of bringing the larger pc
bles to the surface and shaking tt
binding material to the bottom.
Each layer Of gravel should be role
separately. The rolling should beg
at the sides and continue toward tt
y center until the surface is thorough
compacted. The surface layer shou
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