Audubon Republican. [volume] (Audubon, Iowa) 1894-1925, 1917-02-01

inches.
After working the top to a true
surface the walk shall be cut into
slabs with a tool one-eight of an inch
thick, which shall cut clear through
to the sub-grade forming adjacent
and independent slabs, so that when
the concrete has set there shall be a
space between adjacent slabs equal to
the thickness of the tool used.
The upper edges of all slabs or sec
lions shall be rounded to a radius of
one fourth inch. except at street and
alley crossing where the edge shall
be rounded off to suitable slope
/ The surface shall be finished with
a wooden trowl and left slightly
roughened.
Forms shall be so spaced that no
slab shall contain more than thirty
square feet, or have any dimension
greater than five and one half feet
A one-half inch on expansion
joint shall be provided at least once
in every rs feet Similar joints shall
be provided where new walks joins
an old walk, and where the walk in
tersects a curb a one inch expansion
joint shall be provided.
These joints shall be formed by
inserting during construction and
J leaving in place the required thick
ness of prepared felt or similar mat
erial of approved quality made for
this purpose The joints and joint
filling material shall extend through
the entire thickness of the walk.
Mixing Material
The method of measuring the
linz tnv iaJ fnr- hn ,a1.t 1it,ey
water, shall be one which will insure
separate uniform proportions at all
times. A sack of Portland cement
shall be considered one cubic foot.
When the conditions will permit, a
machine mixer of type that insures
the uniform proportioning of the
materials throughout the mass, shall
be used. When it is necessary to
mix by hand, the mixing shall be
done on a water tight platform and
the materials shall be turned until
the mass is uniform in color and
homogeneous. All concrete shall be
mixed by the batch.
The use of concrete that has par
TALLY set or hardened will not be
permitted.
A moderately wet mixture shall be
used, and the concrete shall in all
case be depositd within 80 minutes
after being mixed
Protection
AS soon as the concrete has
hardened sufficiently to prevent be.
ing pitted, the surface of the walk
. shall be sprinkled with water. and
shall be protected from traffic and
the elements for at least three DAYS
No concrete shall be placed when
the temperature is below 35 deg. F
or when it is likely to drop below
30 degrees within "a hours. in nc
case shall concrete be deposited upon
a frozen sub-grade.
SECTION 3
: Material For Concrete Single Course
Work
Cement shall meet the require
ments of the Standard Specified.
/, tions for Portland Cement, adopted
by the American Society for Testine
Materials, Aug. 16, 1909. with al
subsequent amendments and addi
lions thereto adopted by said society
Fine aggregate shall consist o.
clean sand or gravel screenings fret
from loan, vegetable or Other
deleterious matter, graded from fin,
to course and passing when dry {
| screen having one-quarter incl
! diameter holes, and not more thai
Y three per cent shall pass a slew
3 having one hundred meshes per Inca
inch.
S Coarse aggregate shall consist o
] hard durable crushed stone o
{ gravel, graded in size, retained on
screen having one quarter inch diam
J eter holes and the maximum sizt