sptt-inkling with a fine spray of water. All exposed surfaces of unfinished
work will be kept constantly moist by sprinkling at short intervals. For this
purpose not less than one large watering pot for each mixer will be kept in
constant service, and as many more as may be required.
4J. Vater Tank. — The contractor will be required to provide a tank of
10,000 gallons capacity, at a height of 50 feet above top of dam, keeping the
same well filled and connected with hose for the frequent and practically con-
tinuous sprinkling of the finished work.
42* Surface to be Cleaned and Rotsghened. — ^Rock surfaces, and concrete
surfaces more than twenty-four hours old, shall be mopped with a mixture
of neat Portland cement mortar immediately before the application of a fresh
course of concrete, and all surfaces to which mortar or concrete is applied
shall be made clean from any dirt, sand, clay or foreign substances and care-
fully roughened by picking before the application of such mortar or concrete.
Under no circumstances will any concrete be laid in water or in freezing
43* Gmcrete Forms* — Concrete forms must be rigidly held in position
so as to give accurately the exterior surface required by the plans for the
work, being secured against yielding to the operation of ramming. Surfaces
of planking forming exterior faces must give the true, plane surface or
curved surface required for the walls, and shall be dressed to make the
planks of a uniform thickness. The price bid per cubic yard for concrete
in place shall include all lumber, timber, bolts and materials used in the
forms for the concrete. Also all special molds for ornamental arches, out-
line of imitation range work on lower faces as shown by the plans and all
pick fajcing to remove mold marks, and give the exterior face of wall the
appearance of cyclopean masonry indicated on the drawings.
44. Cement. — The contractor will be required to provide a suitable build-
ing, heated when necessary, to maintain the proper temperature, for testing
cement, and also the necessary labor for handling the barrels or packages
and taking the samples for testing purposes. Cement must be on hand
for testing in time to complete all tests before the cement is required for use
In the work, which shall not be more than ten days. It is to be stored in dry,
well ventilated buildings, and protected from deterioration. It may be rejected
for such deterioration, after passing the required tests. Cement must be
stored by carload lots for ready removal of any lot condemned. It must be
stored in strong packages, well lined with paper, so as to be reasonably
secure from air and moisture. Elach package to be labeled with the name of the
STATE GEOLOGIST. 213
brand and the name of the manufacturer. Any packages broken at the time
of delivery may be rejected, or used as half packages at the option of the
45* Veight. — Ordinarily ten per cent of the packages in each carload lot
will be selected for weighing and testing. The average net weight of all
packages in each carload lot will be the average net weight of all the selected
packages. The failure of any one of the selected packages to stand the
required tests will be sufficient reason for the rejection of this carload lot,
in the discretion of the Engineer. Rejected cement will be branded and
immediately removed from the work.
46. Fineness* — Of Portland cement, ninety-eight per cent. (98%) by weight
must pass through a cement wire sieve having 2,500 meshes per square inch,
made of No. 35 wire, S. W. G., and ninety-five per cent. (95%) by weight must
pass through a sieve having 10,000 meshes per square inch, and made of No.
40 wire. S. W. G.
47. Test Briquettes.-:— Test briquettes for Portland cement will be made
both neat and in proportions of one cement to three of sand. Enough watei
only will be used to thoroughly moisten the mixture, which will be forced
into the mold by pressure or tamping, so as to give as nearly as possible the
density of good concrete work. The temperature of the water and of the
room in which the briquettes are made and tested will not be permitted to fall
below 60 degrees Fahrenheit. The sand used in preparing all briquettes shall
be clean, sharp, crushed quartz, retained on a sieve of thirty meshes per
lineal inch, (holes 0.022" square) and passing through a sieve of twenty
meshes per lineal inch (holes 0.033" square.)
48. Initial Set and Hot Vater Test. — Cement mixed neat with about 22
per cent, of water to form a stiff paste, shall not begin its initial set for forty
minutes after mixing with water and after sixty minutes it must be appre-
ciably indented by the end of a wire one-twelfth inch in diameter, loaded to
weigh one-quarter pound. Oment made into thin cakes on glass plates
shall not crack, scale nor warp under the following treatment: Three pats
will be made and allowed to harden in moist air at from 60 to 70 degrees
temperature; one of these will be subjected to water vapor at 176 degrees
temperature for three hours, after which it will be immersed in hot water
forty-eight hours ; another will be placed in water at from 60 to 70 degrees tem-
perature; and the third will be left in moist air.
49. Tensile Strengtii. — The tensile strength will be determined by the
average strength of three briquettes of neat cement and the average
strength of three briquettes of cement and sand. These will be kept
in moist air until set, and then immersed in water until they are put into the
clips of the testing machine, being tested wet. Briquettes prepared from
neat Portland cement shall, after seven days, develop a tensile strength of
not less than 450 pounds per square inch, and after 28 days not less than 550
pounds per square inch. Briquettes prepared from a mixture of one part
Portland cement and three parts sand (parts by weight) shall, after seven
days, develop a tensile strength of not less than 125 pounds per square inch
and not less than 200 pounds per square inch after 28 days. Briquettes pre-
pared from a mixture of one part Portland cement and three parts sand
(parts by weight) and immersed, after 24 hours, in water maintained at 170
degrees Fahrenheit, shall not swell nor crack, and shall, after seven days,
develop a tensile strength of not less than 150 pounds per square inch.
214 ANNUAL REPORT
50* Sandt — Sand will be sensibly free from loam, clay, or other impurity,
sharp, angular, and sillcious. When used in connection with cement tests
in the place of standard quartz, it must give results in each case at least
equal to those obtained by the use of standard quartz. Samples of the sand
proposed to be furnished shall be submitted with each bid and retained in the
office of the Department of Public Improvements as a standard for comparison
during the progress of the work.
51* Broken Stone, — ^Broken stone for concrete: All of the stone used in
the dam must be excavated from the area covered by the site designated by
the Bngineer, selecting and using only such stone as is hard and durable,
of a quality approved by the Engineer, and of such character as to break
in approximately cubical fragments. It will be broken so that no dimensions
shall be greater than one and one-half inches and must be thoroughly screened
from dust and dirt, and washed if deemed necessary.
STATE GEOLOGIST. 215
SPEOnCATIONS FOR CONCRETE ROAD FOUNDATIONS*
In order to give opportunity for comparison, the specifications for
concrete foundations under streets and roads for three cities are given.
The specifications in use in Columbus, Ohio, are as follows :
Sec. 28.-CONCRETE ROAD FOUNDATION.
American Portland Cement* — ^Upon the sub-grade a foundation of Amer-
ican Portland cement concrjete shall be laid to a uniform depth of six (6)
inches, prepared and applied as hereinafter specified.
Sand« -^The sand used in the mortar shall be clean, coarse, screened river
or lake sand of approved quality.
Crtfshed Stone. — The material for the body of the concrete shall be com«
posed of limestone, crushed limestone boulders, or other material, equally
hard and approved by the Engineer, broken so as to pass through a two-inch
ring in its largest dimensions. The material shall be free from all dust or
dirt; no gravel will be used.
Cement. —The cement used will be of the best quality American Portland
cement, delivered in original packages, with the brand stamped or printed
upon the same.
Fineness. —It must be finely ground, so that at least 90 per cent, will pass
through a sieve with 10,000 meshes per square inch.
When mixed with water. and worked up into a cake it must not attain its
initial set until one hour after mixing, nor its final set until after three hours.
Tensile Strength. — ^When mixed neat and worked up Into briquettes, and
exposed one day in air and six days In water, it must develop a tensile strength
of 400 pounds per square inch.
When mixed with three parts by weight of standard sand to one of
cement, it must develop a tensile strength of 150 pounds per square inch
in seven days.
Unsoundness and Color. — Twt) cakes with thin edges will be made of
neat cement, one will be kept under water to note changes of color; the other
will be placed in boiling water, after its final set, and kept there for 12 hours;
if the color changes in irregular spots during a period of ten days, or if
the boiled cake shows any cracks or softness, it shall be rejected as unsound.
Packages to be Marked by Engineer.— All packages of cement must be marked
by the Engineer or superintendent before being used.
Miicing. — One part by measure of cement and three parts of sand will be
thoroughly mixed dry and then made into mortar with a minimum quantity
of water; six parts by measure of crushed boulder, limestone or other equally
hard material, having been previously saturated with water, will then be
incorporated immediately with the mortar.
Size of Cnsshed Stone. — 'Each batch of concrete will be thoroughly mixed,
the mixing to be continued on the board until each piece of stone is com-
pletely coated with mortar. It will then be spread and at once thoroughly
compacted by ramming until free mortar appears upon the surface. The
whole operation of mixing and laying each batch will be performed as
expeditiously as possible and with the use of a sufficient number of skilled
men. The upper surface will be made exactly parallel with the surface of
216 ANNUAL REPORT
the pavement to be laid, and when in place all wheeling, working or walking
on it must be prevented until it is sufficiently set, and in no case will any
material be wheeled upon the foundation until 24 hours after having been
put in place.
Materials must be brought upon the foundation in barrows, unless delivered
upon the same from the sidewalk.
STATE GEOLOGIST. 217
The specifications in use in Washington, D. C, are as follows :
4 Concrete Base. — ^Upon the bed (sub-grade) thus prepared there will be
laid a four (4) or six (6) inch foundation of concrete, as directed, made of
broken stone and gravel, sand, and natural cement in such proportions that the
quantity of gravel will be equal to the volume of voids in the broken stone,
and the sand and cement, mixed in the proportion of one (1) part cement and
two (2) parts sand, will be 20 per cent, in excess of the volume of voids
in the combined gravel and broken stone.
5* Hydratflic Cement. — The cement in use shall be a natural hydraulic
cement, and shall conform to the current specifications for supplying such
liydraulic cement to the Engineer Department of the District of Colum-
bia. No hydraulic cement shall be used upon the work until it has been
tested in the office of the Engineer Commissioner and accepted by him, the
tests to extend over such length of time, not exceeding twenty-eight days,
as the Engineer Commissioner may think necessary. The cement, while in
storage or ui>on the work, while being hauled upon the work, shall be
properly protected, and no cement shall be used which, in the opinion of the
Ehigineer Commissioner, has been injured by age or exposure. The cement
shall be kept by the contractor in store, under proper cover, in the city of
Washington, and subject to inspection for at least ten days before it is
used on the streets, and if deemed advisable by the Engineer Commissioner,
twenty-eight days. Should the contractor's work be delayed by his failTU*e
to keep himself supplied with the necessary amount of approved cement,
the District shall have the right to furnish him with tested cement from the
stock on hand at its warehouse and charge said contractor with the cost
of same at the rate of seventy-five (75) cents per barrel for each and every
barrel so furnished, and collect the amount due therefor from any moneys
found to be due to said contractor by the District.
6. Sand* — The sand used shall be clean, sharp river sand, containing
both fine and coarse grains, but free from sewerage, mud, clay, mica, paper,
leaves, chips, and other foreign matter, and not showing, when shaken with
water and after subsidence, more than five (5) per cent, by volume, of silt.
7. Broken Stone. —Stone used in concrete must be hard, durable, and
properly broken to a size small enough in their largest dimensions to pass
through a ring two (2) inches in diameter, and none smaller than \A inch
can be used. It shall be thoroughly cleansed from all foreign substance
and shall be screened and washed, if so ordered by the Engineer. Sand,
detritus, or any material other than hard, angular fragments of stone will be
considerjed foreign substances.
8. Gravel. — Gravel shall be clean, washed gravel, and shall not contain
pebbles greater than one and one-half (1^) inches in their largest dimensions.
9. Water. — Water used for mortar and concrete shall be fresh and clean,
free from earth, dirt, or sewerage, and shall be used in such quantity as the
Engineer may direct.
JO. Platforms.— Platforms shall be provided upon which all sand, gravel
and broken stone shall be placed when brought upon the line of the work,
and kept there until used.
n. Mixing. — Concrete may be mixed by hand labor or by machinery, but,
in either manner, the thorough incorporation of the several materials required
will be insisted upon. If machinery is employed for the purpose, its operation
218 ANNUAL REPORT
must be subject to the direction of the Engineer Commissioner, as due con-
sideration must be had as to the style, design and adaptability of the machine
used to produce a mixture acceptable to him.
If the materials are mixed by hand labor, the operation must be performed
on platforms of water-tight construction by competent labor, in accordance
with the following instructions:
The dimensions of the platforms must be such as to provide an area
sufficient to allow the entire mixing operations to be done upon them in a
thorough and complete manner, in accordance with these specifications, and
will depend upon the volume of the material used in the batch; in batche^
requiring a full barrel of cement, the dimensions of the platform will not
be less than ten (10) by twelve (12) feet, or its equivalent area, of suitable
form, and no larger batches than these shall be made by hand labor.
The required quantity of sand will be spread upon the board or platform,
dry, and covered with the cement, in its proper proportion, when the material
shall be thoroughly mixed and incorporated, by turning It with shovels not less
than six (6) times. When sufficiently mixed, the mass will be so spread
and shaped as to form a basin for the water which is to be added to make
the mortar. The required quantity of water will now be poured into the basin
thus formed and incorporated with the dry substance, by the use of hoes and
shovels, so as to prevent any loss of material. The mortar will then be
spread over the surface of the platform in an even and regular layer, pre-
paratory to the reception of the stone and gravel, which, hfLving been pre-
viously drenched, will immediately be deposited and evenly spread over the
When the entire quantity of the aggregate has been deposited and spread
on the platform, as above, the mass shall be thoroughly mixed by turning
it crver with shovels, not less than four (4) times, until every particle of the
metal has been completely enveloped in mortar; and until every particle is
so enveloped, to the satisfaction of the EIngineer Commissioner or his agent
the mixing process must be continued. The order of turning must be so
regulated that the last turn made will place the material in a single pile at
or near the center of the board, preparatory to its removal to the place for it
in the work.
In removing the concrete from the platform care must be taken to pre-
serve the incorporation, which can best be done by shoveling it from the base
at the edges of the pile, toward the center of it, and at the same time cutting
down the apex of the pile with a hoe or shovel, in such manner as to avoid
an accumulation of loose stones.
Stone and gravel used in the concrete must not be drenched in the vehicles
used to deliver it upom the platform, unless proper arrangements are made
to drain the receptacles, but shall be wetted before they are placed therein.
Concrete shall not be used after it has shown evidence of beginning to set,
and no concrete that has omce set shall be used as aggregate for a new batch.
The work of mixing and spreading shall be done as expeditiously as possible.
Any material condemned as unfit for use, or not conforming to the spec-
ifications, must be immediately removed from the site of the work. The con-
tractor must provide suitable facilities to determine the quantities and quality
of the materials used in the concrete, so that they may be readily ascertained
at all times.
)2« Laying* — Grade stakes of suitable character must be set to determine
ana regulate the grade for the material as it is deposited in the work, and
straight edges or other equally efficient devices used to insure a regular and
STATE GEOLOGIST. 219
uniform surface between the stakes, and as the concrete is placed upon the
sub-grade it must be regulated with shovels by skilled labor to conform to the
grade immediately upon its emplacement, and then rammed or tamped suffic-
iently in place to form a solid and compact mass. The labor necessary to spread
and compact the concrete must be other than that required to mix it In com-
pacting the material in place the operation of ramming or tamping must be
continued until the top surface is regular and the water in the mass begins
to appear on the surface. No mortar that has been prepared for the purpose
of forming a new batch of concrete shall be taken to plaster any rough or
improperly tamped places that may appear in the base, as ramming or tamp-
ing must be the only means employed to obtain a smooth and regular surface.
The removal and placing of the concrete to grade should be performed in
such a manner as not to disturb the uniformity of the mixture.
Any lack of compaction or evidence of inferior setting in the base will
be sufficient reason to require its removal and new concrete substituted for it
If required, the earth in the sub-grade will be dampened before the con-
crete is laid, and the concrete base shall be sprinkled and wetted as often
as required during dry or hot weather to prevtot damage from too rapid
No cement concrete base shall be laid during very cold or freezing weather
without permission of the Engineer Commissioner and then only under such
special regulations and instructions as he may think necessary.
No hauling must be done over or upon the base, for any purpose until
after it shall have sufficiently set to withstand fracture, and, if necessary,
the base shall be planked before any hauling Is done.
220 ANNUAL REPORT
The specifications in use in Peoria, Illinois, are as follows :
28» Thickness* —Upon the sub-grade prepared in accordance with the
specifications for grading, will be laid a concrete foundation six (6) inches
thick after being compacted.
29* Pit>portions« — The concrete shall be composed of one (1) part by bulk
of American Natural Hydraulic Cement, one and one-half (1%) parts by
bulk of clean, sharp sand, and four (4) parts by bulk of broken stone.
30* Intention of Proportions, — The proportions herein specified are in-
tended to prcwiuce a concrete in which the mortar will fill all the voids, and
the proportions will be so adjusted that when rammed in place free mortar
will fiush to the surface.
MIXING AND SPREADING CONCRETE.
3 J, Mixing Sand and Cement* — The sand and cement shall be thoroughly
mixed dry in a tight mortar box and then made into a mortar of the proper
consistency and thoroughly worked over with hoes. Broken stone thoroughly
cleaned of dirt, drenched with water, but containing no loose water in the
heap, shall then be added to the mortar in the proper proportion. The con-
crete will then be turned and mixed until mortar adheres to each fragment.
32, Consistency of Concrete, — ^The concrete thus mixed shall have such
a consistency that when rammed the mass will not shake like jelly; but will
when struck, compact within the area of the face of the rammer without
displacing the material laterally.
33, Immediate Use of, — The concrete thus prepared shall be immediately
placed in the work. It shall be spread and thoroughly compacted by ramming
until free mortar appears om the surface.
34, Mixing and Laying, — The whole operation of mixing and laying each
batch of concrete shall be performed in an expeditious and workmanlike
manner, and be entirely completed before the cement has begun to set.
35, No Re-tempering, — No re-tempering of concrete will be permitted, and
concrete in which mortar has begun to set will be rejected.
36, Conform to Grade* — The upper surface of the concrete shall be made
to conform exactly to the form of the pavement to be laid, and shall be made
perfectly smooth by thoroughly brooming with wire brooms.
37, Protection, — As soon as laid, and before the top becomes dry, the
entire surface of the concrete foundation shall be covered with one (1) inch
in depth of clean sand to protect it from the sun and wind. The sand so
spread shall be kept moist until the pavement is laid.
38, Time for Setting, — ^No driving over the concrete foundation will be
permitted, and it shall be allowed to set for four days before any further
work shall progress cm the same, and any damage done by passing over
it shall be repaired by the Contractor without extra pay.-
39, Minimtim Temperature When Laid, — No concrete shall be laid when the
temperature at any time during the day or night falls below thirty-five (35)
STATE GEOLOGIST. 221
SPECIFICATIONS FOR CONCRETE CURB.
The specifications in use in Peoria, Ills., are as follows :
SPECIFICATIONS FOR CONCRETE CURB.
1. The curbing herein specified shall be constructed on
Street, from Street
2. The concrete curb shall be inches in
thickness and inches wide, with the upper face corner
rounded to a radius of one and one-half (1%) Inches.
3. The curb shall be constructed on the ground in alternate sections,
and the top edge shall conform to the line and grade given by the £3ngineer.
• 4. After the necessary excavation has been made along the line of the
proposed curbing, there shall be laid a foundation of cinders twelve (12)
inches wide and six (6) inches in thickness after being compacted; this bed of
cinders to be flooded with water and thoroughly rammed to a true and even
surface with a hand rammer weighing not less than forty (40) poipids.
5. Upon this bed of cinders shall be set the curb, which shall be con-
structed so as to form a solid mass, divided every seven (7) feet of its length
into separate stones, and the concrete i>ortion of which shall be composed
of one (1) part best, imported Portland cement, three (3) parts clean, sharp,
well-screened sand, and five (5) parts hard limestone or granite crushed to
such size that the fragments shall not be larger than one (1) inch in the
6. A facing one (1) inch in thickness shall be constructed on the top