Bismarck daily tribune. [volume] (Bismarck, Dakota [N.D.]) 1881-1916, 1912-04-27

between tho larger pieces. Gravel OBJ
tained from streams is usually inferior
to pit gravel for the reason that the &C.
ton Of the water has worn the pebbles
smooth and practically all the fine
binding material has been removed by
the same agency. Even If clay or loan
IA mixed with river or creek gravel the
result is not likely to be as satisfactory
as that obtained by the use Of pit gray
el. Pit gravel frequently contains too
much clay or earthly matter, while river
gravel may have too much sand. III
such cases it Is sometimes advisable to
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 u macadam road.
In the handling Of the gravel care
should be exercised not to separate the
binding material from it, nor should
this binding material be allowed to
settle to the bottom in spreading the
material over the road surface. It
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.
1opuo r0ysk ~ thu rpo <c,,nH 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 60
per cent by weight Of the gravel should
be pebbles above one-eighth inch in
size, and there should be no pebbles in
the bottom layer that will not pass
through two and half or three inch
ring, and in the top layer there should
be NO pebbles which viii not pass
through a one and one.half inch ring.
Not over 20 per cent Of the mass
should be clay, and this should be UNI.
formly mixed and should contain no
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. It is
quite as important to have a solid
foundation for gravel road as for
macadam road. Gravel will compact
to about 50 per cent Of its depth, loose
measure, provided earth shoulders are
placed on both sides Of the road to
prevent the wasting away Of the
gravel on the sides. If gravel is abun-
dant, however, these shoulders may be
built Of gravel instead Of with earth,
or the road may be surfaced with
gravel from shoulder to shoulder. If
the compacted depth Of the gravel
road is to be eight inches and the
width twelve feet it will take about
$3.50 cubic yards Of gravel to the mile,
and it is best to make the first layer
0OOuC OLA AASHCS Ill uCpIuS AOOoO A1Cuo~
ure, and the second layer about four
inches in depth, loose measure.
Gravel should not be dumped direct
" on the road, as this will usually re-
suit in rough, uneven surface. If
specially devised spreading wagons
are not used the gravel should be
dumped on boards and spread from
them on to the road.
The gravel should be placed on the
road commencing at the epd nearest
the gravel pit, in order that the teams
will aid in packing the material. A
spike or tooth harrow may be used to
advantage in spreading the material,
but If the gravel contains only small
amount Of binding material the har-
row should not be used, as It will have
the effect of bringing the larger peb-
bles to the surface and shaking the
binding material to the bottom.
Each layer Of gravel should be rolled
separately. The rolling should begin
at the sides and continue toward the
center until the surface Is thoroughly
The surface layer should