The Caucasian., 1903-06-07

ing test, Hydraulic must not crack or
become COnturted along edges III two
days
Time Of sct-PoltIani initial set 45
minutes final set 10 hours: tIvdraullC
initial set - minutes; final set 10 hours.
/ Tensile strengtIl-Ncat brlqucttes,
strain applied uniform rate O to 400
pounds per minute: Portland day l25
pounds, ! days $50 pounds; Hydraulic
day IS pounds. I days I25 pounds.
| 52.-Binder: Upon the concrete base
will be laid the binder course composed
of clean broken stone and asphaltic c.
lent. The broken stone must be equal
in quality to the stone specified for the
concrete base the fragments varying
Iuniforn1ly in size from one inch to one
half inch on longest diametcrs.
| The broken stone will be heated to a
temperature of not less than $50 or
more than 900 degrees Fahrenheit. and
thoroughly mixed with as hattie ce-
nent of the quality specified for the
pavement, at a temnerature of from 275
to 325 degrees Fahrenheit, the frag-
ments of stone to be perfectly coated
with the asphaltiC cement in sufficient
quantity to bind them firmly together
when the mixture has been spread upon
the concrete base and finally COM
dressed. Should the binder appear dull
| from OverhcatIng or lack of cement. it
will be rejected
This mixture of broken stone and as
ptaltic cement, while hot. will be hauled
upon the work and spread upon the CON
crete base to such depth that when 'hor-
Oughly cOmpacted it will give uniform
thickness of one-half inch As soon as
it is spread and while in hot plastic
condition. the binder shall be cOmpacted
by rolling with a roller operated by
steam power and giving a weight press
TIRE of not less than Us pounds per lin
cal inch of roller. Such portions of the
binder course as can not be rolled will
be thoroughly compressed by ramnling
The concrete base shall have firmly set, |
and shall have a dry surface when the
binder is placed upon it.
The surface of the binder course shall |
be made exactly parallel with the re-
quired surface for the finished pave
ment. and the fragments of broken |
stone, throughout the entire course,
firmly bound together.
53.-Wearng surface: Upon the bind
er course will be laid the pavement or
cement, sand. and carbonate of lime.
The asphaltic course will be an admix-
ture of aspha1tum and heavy petroleum
oil
The asphaltum used will be refined
from the best quality of crude aspl1al-
tutn, obtained from the pitch lake in the
Island of Trinidad. or from the pitch
lake in the State Of Bermudez, in the
Republic of Venezuela, South America,
Or from the AIcatraz mine, Santa Bar
para County, California.
The asphaltum must be refined, and
50 far as possible freed from all foreign
organic matter and volatile oil, and
must contain at least sixty (6o) per cert
# biturnen soluble in bisulDhide of car
lon
The petroleum oil must be freed from ,
:oke and other impurities, and brought /
o specific gravity of from 19 TO 2e I
legrees Baume. and a fire test of 400 !
'egrees Fahrenheit.
The refined aspha1tttm and the heavy
,etroleum oil will be melted and mixed r
II the following proportions by weight, | !
0 form the asphaltic cement, viz: Re
med asphalturn 100 parts petroleum
ii from 1a to IS parts. /
The sand must be reasonably clean, .
and sharp. said cleanness !
nd sharpness to be determined by the =
ity engineer, and of such a degree of =
neness that thirty (3o) per cent will =
ass No. 80 screen, and all of it will =
ass a No. 20 screen.
The carbonate of lime will be in the
5r1n Of powder produced from clean,
ound limestone Of st1ch degree of fine I,
ess that sixty t6o) per cent by weight 2
Ill pass No. 200 screen, and all of it !,
Ill pass No. so screen. Il
Il1e asphaltic cement prepared in the "
Ian1er specified will be mixed with the n
md and carbonate of lime in the fol- o
wing proportions by weight, viz: AS q
1altlc cement 10 to 10 per cent. sand
to 20 per cent; carbonate of lime 10 te
J IA per cent.
54.-1he following method of pre- n
aring and laying the pavement corr1po- W
ton or wearing surface will be OBJ H
rived. as
In order to make the pavement homo p
nous the proportion of aspha1tic ce-
ent must be varied within the limits j.,
eeifled, according to quality and char ~
Ter of the sand. The proportion Of ",
rbonate of lime NAV be reduced when =.
G character of the sand will permit. 9s 9s
The sand and the asphaltic cement e'
III be heated separately to about 200
grees Fahrenheit The pulverized car m
mate OF lime while cold, will be thor IN
ghly mixed with the hot sand in the
attired proportions, and the combined ST
nd and carbonate of lime then mixed pc
tn the asphaltic cement. at the re- pc
ired temperature, in the proper pro- 1
rt1efls, and by suitable apparatus to
eet thoroughly homogeneous compo- De
ion. no
The pavement composition or wear an
I, surface prepared in the manner thus ire
Heated will be laid on the binder fir
urse; it will be laid to such depth af,
will give a thickness of two (2) vo
hes after being consolidated by roll Fa
y 1t will be delivered on the work for We
IN the pavement at temperature of lins
less than $50 degrees Fahrenheit nor frff
re than 31o degrees Fahrenheit. thu
he delivery temperature must be ree
tY~fi x31Sa ~ l