The Detroit times., 1911-06-21

hnimates me, anu nothlns more, "a
again and again urging the nccessit!
of an up-to-date modern ard compre
hensive test--the rattler test.
Respectfully submitted.
4 VIM. b. THOMPSON.
On motion OF Aid. Grindley the vot'
by which so much of the proce edlnSi
OF the preceding session of the Counci
as Is specified In the mayors veto mes
sage was reconsidered.
i Aid. Watson moved that the mat
ter referred TO be adopted notwith'
standing the veto OF his honor the
mayor. which motion prevailed as fol
lows:
/ Yeas-Ald Allan. Brozo. burton
Deimel, Ellis. Field, Gilman. Gr,ndley
| HARPER, Hindle. Heating. Koentg
Knapp, Littlefeld. Lodge, Mason Ne Mer'
schultz. Theisen. Thompson. Tossy
Walsh. Watson, Zoelier, and the Pres
Iident-2s.
otBrien, skrzycki.5
FROM THE SAME.
To the Honorable the Common Council:
Gentlemen-On May 26th. 1911, AL
derman Patrick OBrien. OF the Tenth
Ward, submitted TO the Executive or
fce samples OF material used In the
concrete foundation on certain streets
OF his ward. He stated that the sam
pies submitted Represented 30 per cent
| OF the material used by the contrac-
tor. They were submitted by the
Secretary TO several competent judges
and on their statements that they rep
Iresensd a low quality OF Stag, i deem
ed II OF sufficient Importance TO have
an examination OF the material made
by one well versed In concrete founda-
lions and the several materials which
should enter into them. The engineer
selected by this office Is Captain j. n.
Poole. formerly engineers of the United
States Army, and government expert
I'm vast concrete construction work In
washington, d. c., the Philippine Is
lands, and on the Great Lakes. Cap
tain Poole's report is as follows:
Mr. Ernest w. Kurz
Secretary to the Mayor.
Detroit. Mich.
Sir---In reply TO your letter OF May %.
1911. accompanied by samples of mate
rial used In the concrete foundation of
Spruce street, between Wabash avenue
and Twelfth street, and referring 20 the
copy OF the specifications for brick pave
ment adopted by the Department or Pub
lie Works, which was handed TO me by
you. and TO the additional samples which
have been furnished. / have the honor
| to submit herewith my opinion OF the
material represented by the samples. us
ing as requested by you the above men
toned specifications as a working basis
All OF the samples submitted appear
to be pieces OF Stag which. by the word.
ing OF the specifications. may be used
as a coarse aggregate In concrete for the
foundation OF the brick pavements con-
structed under these specifications. The
other alternative materials mentioned IN
the specifications are, broken boulders
granite. syenite, or hard limestone. AL
or these latter would be admissible as
good broken stone, which Is the most
generally used coarse aggregate for the
purpose.
Although other types of foundations
are sometimes used, cement concrete, US
ually inches in thickness, but occasion
ally TO 3 inches thick for heavy traffic
l..AN g. AWnf q
class pavements. and where thickness
OF foundation OF inches IL used the con-
crete should be OF high grade. With the
proportions OF cement, sand and coarse
aggregate called for by the specifications
a high grade foundation concrete would
undoubtedly be obtained with good brok-
en- stone, and the only question IL would
the Stag represented by the samples sub
or even one advisable for use In the
foundation for brick pavements In
large city.
The stability OF any pavement de-
ton on which the surface rests. and a
given intensity OF traffic requires a
foundation OF corresponding stability, re-
gardless OF the character OF the surfacing
ciaIiy applicable to brick pavements,
which being made of comparatively small
blocks, are more easily injured by de-
rangement OF the blocks and consequent
ly require very carefully constructed
Crushed Stag from blast furnaces. II OF
proper chemical composition and not too
honey-combed with pits and air holes.
crete. The Stag should be compast
homogeneous and OF a gray or slightly
blush color. The acid constituents Isl
o22 and Al 2o2). should not exceed ~
per cent approx. and the basix constitu-
ents should not contain an excess OF
lime. Slags having acid constituents ex-
ceeding IS per cent become on cooling
more or less CLASSY and vitreous. break
and are not suitable for use as a coarse
aggregate In concrete. Usually slags
having more than so per cent lime will
fall TO powder on cooling. An article in
the Engineering Record OF January Il.
1905, gives the result OF a series OF
strength tests made on concretes In which
ten different coarse aggregates were
used. Stag, presumably OF good grade,
II rated sixth as an aggregate. being In
ferior. according TO these tests. TO trap,
granite, gravel, marble and limestone.
The Stag I'm the samples submitted by
you seems TO be OF the proper chemical
composition, but II is practically all very
badly pitted and honey-combed. The
holes and pits are, many OF them. one
quarter Of an inch and larger In diam
eter. Sample "a was easily broken
and shows structure honey-combed
throughout. The strength and density OF
the concrete would be greatly reduced by
the interior holes while the outside pits
would make the proper mixing OF the con-
crete very difficult matter. Thorough
mixing Is a very important step in max
ing good concrete and the deeply pitted
surfaces OF the Stag samples submitted
would be very difficult TO coat thoroughly,
especially by Handwriting on boards.
which the specifications seem to contem
plate.
Everything considered. am OF the
opinion that concrete made according
to the specifications with crushed Stag
similar TO the samples would not be
as high grade as that produced by
using any of the other alternative ma
terialsi- and further that the use OF
the material submitted, as a coarse
aggregate In the concrete foundation
for brick street pavements I'm Detroit
II not advisable.
Very respectfully,
(Sgd) J. II. POOLE
samples accompanying.
You will infer from his report that
Stag presumably OF a good grade a.
rated SIXTH as an aggregate being
inferior. according to tests made 10
trap. granite. gravel, marble and lime
stone. You Will also infer from the
report- thai tha- graded --,ftrrrft--
ted--tand ] viii state here for the
benent OF the Common Council thar
most liberal samples were given the
captain. selected under the most care
ful conditions by Secretary Kurz ana
Ofhcer James Walsh on various streets
OF the city)--is net equal IN analifv
20 what n generally termed slar In
the opinion OF eoncrste experts. It IL