Evening star. [volume] (Washington, D.C.) 1854-1972, 1872-04-11
Concrete rayeu.cn,a.

uTon the subject CT concrete rsvemeuts, have
ccnelGded their labeTs
The commission met March 18th and 18Th In
New York, and March 10Th and 9Th in Phiia-
deiPhia, ard they report that during this pc
rcd they examined sll the pavements laid IN
these cities, and notably those in the parks and
public squares. OF the large number and va
riety put down in this country IL may be stated
that good samples OF the most important of those
which seemed to offer any reason asle hope OF
success were found on one al OF these squares,
and presented all the advantages fJT Obserya-
tion asto length of time laid, abrasion 10 which
they had been exposed, and conditions under
such exposure, which the board deemed OF value
for the purposes OF their investigation. The
pavCments so examined were pat down by the
following companies II he ScTimshav Patent
Pavement company, the Scharf Pavement
company, the Evans Pavement company, the
Day Nuicanite Pavement company, and the
Filbert FulcaDite Pavement company. together
with some others, whose operations had been
too limited to warrant special mention. Those
enumerated had been in use for various periods
from the year 1eoI TO date and exhibited favor
we!l-tormed and compact surfaces, with tair in
dIcatloDs OF continued durability.
NEARLY ONE HUNDRED PATENTS
for concrete paycmenis have been issued, and,
referring 10 this fact, the report says when il is
further ebseryedth for the purpose OF full
filling the fiimsy requirements OF the law, the
patentees have been permitted 10 include in
their specifications, under the pTetence of using
them As necessary ingredients, such rubbish as
sawdust, shayings, charcoal dust, peat, &C., it
may be reasonably questioned how far the ope-
rations OF that branch Of the government serves
TO foster ard encourage honest talent and in
dustTy. Less than fifteen OF these patented
compositions present to-day any claims to the
attention OF practical men, and perhaps not
one-halG OF these more than partially succeeded!
and
SOME HAVE TOTALLY FAILED
for want OF correct knowledge and experience
in combining and manipulating III aterials on
the laIt Of the nafEntPp. a naVpmpuT
posed of broken stone, gravel, sand, or their
equivalents il they can be found, united with
asIhalt ard coal tar, bitumen properly pre-
pared, will, without doubt, make a cheap and
durable roadway; but no process now in use
Offers such conditions OF uniformity in the ma
nirua'i' OF The work as To warrant assurances
OF substantial success. The btuminOus lime
store Of France. which is used both in that
country and London, is
THE Fest MATERIAL KNOWN
Tor this class Of work. 1t contains ninety parts
OF carbonate @: lime to ten parts OF bitumen.
No stone to equal that has yet been discovered
in this country, and what effect this changeabe
climate will have ON it is OF course unknown.
Samples are to be laid here during the present
year. 1t has not been possible, so far, to pro-
duce, by any mechanical means, a composition
which meets the necessities of a pavement so
well as the limestone. Asphalt and coal-tar
bitumcn, however, have been substituted and
answer very well, although much has yet to be
learned of their chemical and me chanicsl treat.
ment. Ore of the principal objections to AS
phalt is the manner in which it is prepared for
shipment, the operation of refining il being very
imperfect, which seriously impairs its value,
and renders somewhat uncertain the results
where fixed rules as 10 quantities have been es.
tablished. IL is elsO thought that there is
A SERIOUS OBJECTION
to the manner in which the asphalt is treated
tor the purpose OF separating these foreign sab
stances. The heat is also applied in an irregu-
lay and unsystematic manner with such care
lessness a. 10 frequently destroy much OF the
valuable part OF the asphalt. and in this manner
~ VI inf nIs nj la nfra.
who, with ever so sound a formula, will neces-
sariiy fail of a practical result, on account OF
this defective material. They advocate in the
use OF prepared asphalt and coal bituman
more extended, systematic and scientific pro-
cess, which will necessarily enhance the first
cost OF the material, but will certainly add to the
value of the pavement. The work SO far done
has been altogether in the shape OF
SERIES OF EXPERIMENTS,
and viii continue so until a well-developea and
perfect system is obtained. The use of both
crude coal oil ana pine or wood tar is unequiyO-
cally condemned, and the use of steam in the
preparation of the article is advised, as also
strict supervision of the work, in order that the
proper degree OF heat may be assured. The
state OF the soil and its preparation should also
receive careful attention, and from that all the
Work on the pavement to its top layer.
PREPARATORY TO LAYING TIE PAVEMENT
the ground should he shaped and compacted TO
carfully prepared surface. Soft or uncertain
ground, and special localities where erratic de-
Iosits OF Objectionable materials occur. should
be remedied by replacing them with stone,
gravel, sand or other reliable substitutes. Moist
marshy or springy ground should be treated 50
as 10 prevent TIE possibility Of settling or the
MOI king up of tn " -'.r trough the structure.
Lis surface thOUlU have suitable browning 10
carry of any water that might ind its way
through the upper courses, and thus reduce the
Isk OF damage by frost. \ layer of sand, gravel
or other substance should be placed over the
entire surface. on this road-bed n LAYER or
iounCation Of carefully made concrete, varying
III thlckness according to the use 10 which the
roadway r. TO be subjected; this to be allowed TO
set properly, as the board are of the opinion
that
THE STRENGTH AND DURABILITY OF THE ROAD
largely depend upon the thorOuShneSs with
which this part OF the work is done. The finish
lng course should not be placed upon this
until all moisture is expelled as the
presence OF water seriously interferes with the
adhesive qualities of the bitumen. No material
should be prepared during wet weather. Geo
graphical position will vary somewhat the rela-
tive proportions OF certain ingredients. Theupper
layer should be laid with regularity and thor
eugh rolled, in order to secure uniform soliditv
ana density OF surface as insuring more complete
impenetrability to water. This material will
consolidate under the pressure OF traffic, and the
surface WIZ harden to some extent by exposure.
1t cautions against the use of materials t.
harden the surface unless great care is taken.
HE LEST TIME FOR LAYING SUCH PAYMENTS
Is from April l to December /, as damp and
frosty weather is decidedly unfavorable. A
chapter Is then devoted TO the best method OF
repair ing the pavement, and the report closes
with reference to the good qualities of bensf-
cial r. suits OF aprOperly laid concrete pavement
and summing up of what is necessary to Sc
cure its proper construction.
The report is signed by NJ. A. Kellogg, Engi-
Department OF Parks, New York:
John Y. Culyer, BROOKLYN Park Company; John
ID. EstabroOk, Principal Assistant Engineer
aiImount Park, Philadelphia; A. b. Mullett
Chief Engineer Board OF Public Works, ID. g.:
). Z. Brown, Board of Public Works, ID. q.
~
BALTIMORE ANNUAL CoNFERERCE OF THE
AFRICAN NJ. T.. CHURcH.-The fifty-fifth an
nual session of this body will assemble in the
Union Bethel Church, on NJ street, between
18th and 10th, in this city, on Saturday morning
next. Bishop Wayman will preside over the
body. The annual sermon will be preached on
Monday afternoon, April 18th, at 4 O'Clock, by
Rev. DIR. Revels, OF Baltimore. The annual
missionary sermon will be preached on We'd
nesday afternoon, April 18th, by Rev. L. A.
Hall. There will be about sixty ministers in at
tendance at this session. This being the con-
ference at which delegates are to be elected to
the general conference, will make il of more
than usual interest. This denomination of
have eight churches in the District OF
Columbia. They are presided over by the fol-
lowing pastors:-Israel Church, South Capitol
street, Rev. G. T. Watkins; Union Bethel, N
street, Rev. ID. p. Seaton; st. Paul, Rev. r. A.
Hall; Georgetown, Rev. W. d. w. Schureman
Pisgah, Rev. w. NJ. johnson; Good Hone and
Potomac City, Rev. Daniel Draper. Wayman
Chapel, East Washington, is supplied by Rev.
James Reed, local preacher. The anniver-
sary Of the Missionary Society will be held on