John C. (John Cresson) Trautwine.

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Placing,

freezing weather, 44 a

dropping from height, 33 a

delay in , 20 a
Compacting ;

density, 17 a 21 6, 21 c, 45 a

fire, 46 e

SETTING.

Setting,

expansion during ; 4 h
rate of ;

salt, 4 c; consistency, 4 d

aeration, 84 a

addition of agg, 84 a

gypsum, 51 a

lime and gypsum, 51 c

calcium chloride, 51 a, 51 6

AGE.

Age;

strgth, 12 a, 14 a, 18 a, 81 g,

86 g, h, i

elastic modulus, 61 b
permeability, 61 c, 78 6, 79 j

LAITANCE.

Lai tan ce ;

consistency, 61 d
permeability, 47 b, 60 a, 61 d
strgth, 61 d
thickness of ; 61 d

REGRINDING.

Regrinding; 31 c, 77 a

C8



FINISH.

24 a, 32 a. 44 6



Finish ;

water-tight ; 47 h, 57 a, 93 a
Soap ami alum mixture ; 47 h
Paint ; 66 a

PROPERTIES, BEHAVIOR.

Density ;

fineness of sand, 79 e

sand vs screenings, 79 c

gravel vs stone, 79 c

size of agg, 79 6

proportions, 9 c, 17 a

grading, 79 d

lime paste, 82 d; clay, 4 a

consistency, 61 a

mortar, proportion of , 79 /

compacting, 21 6

permeability, 72 6, 79 g

durability, 72 6; strgth, 72 6

plasticity, 72 b
Voids;

spheres of uniform diameter,456
Volume; 21 a
Shrinkage ; 21 a, 42 a, 73 a
Absorption ; 55 a

character of sand, 62 a

sand vs screenings, 55 a

clay and loam in sand, 56 6

strgth, 62 a
Ductility; 16 a, 30 a, 36, 38, 48,

81 e,f

Flow ; 58 a
Durability ; 72 6
Plasticity ; 72 6
Soundness ; oil, 68 a

Strength.
Strength ;

ingredients, 50 a
nat and Port cem, 14 a, 19 a
typical mix, 86 /
sand, character of , 62 a
sand, fineness of , 52 6, 79 e
sand, grading of , 86 e
sand vs crushed limestone, 50 a
proportions, 14 a, 18 a, 19 b
agg, character of , 19 6, 83 a
agg, size of , 39 /, 79 6
gravel vs stone, 14 a, 79 c
sandstone vs shale, 11 a
cinder cone, 15 a, 23 a



1138



CONCRETE.



Directory to Experiments, pp 1140-1183.



CONCRETE

screenings, 86 6

mica, 87 a

proportion of mortar, 79 /

dirt in sand and agg, 19 c

clay and loam, 34 a, 39 g, 52 b,
56 a

clay and alum, 80 a

lime, 80 a

consistency, 61 a, 83 a

salt, 19 a

mixing, 12 a, 22 a, 27 a

re-tempering, 28 a

delay in placing, 20 a

laitance, 61 d

re-grinding, 77 a

age, 12 a, 14 a, 18 a, 81 g, 86 i

cold, 19 a

density, 72 a, 6

fire, 46 d, 70 d to /

oil, 63 a to c, 68 6

absorption, 62 a

reinforcement, percentage of ,
81 g

columns, 35 a

reinforced beams, 81 g, h

uniformity, 86 g, h

safe, 9/i, 12 6

compressive , 85 a, 86 i

tensile , 85 a, 86 i

transverse , 85 a

torsional , 81 c

shearing , 81 b, e

shearing , in beams; 81 h
Fatigue ; 16 a, 48 a, 76 a to e
Unit stress;

unit stretch, 67 a, 81 a

Elastic Properties.
Elastic properties ; 67 a, 81 a

Potenzgesetz (law of powers),
67 a

fire, 70 c

neutral axis, position of , 83 a
Elastic limit;

adhesion, 88 a; fatigue, 76 c
Elastic modulus ; 81 a

size of agg, 70.5

proportions, 70.5, 81 a

consistency, 61 b, 81 a

age, 61 b

fatigue, 76 c; fire, 70 c

columns, 35 a

Permeability.
Permeability ; 47 a to I, 78 a to

d, 79 g, 82 a

cem, Port & nat , 65 a
proportions, 9/, g, 13 a, 6, 25 a,

43 a, 65 a

excess mortar, 13 6, 43 a, 79 g
aggregate, 79 g, i, j
grading, 93 a
gravel with sand, 9 g
sand, screenings, stone, gravel,

79?
clay, 4 a



Continued.

clay & alum, 80 a
lime, 80 a, 82 a, c
lime & sand, 82 6
consistency, 33 a, 47 c, f, 61 a
laitance, 47 6, 60 a, 61 d
density, 72 6, 79 g
waterproofing, 47 h, 80 a
soap and alum mixture, 47 h
finish, 47 h, 57 a, 93 a
reinforcement, 47 /, g
sunshine, 47 e

pressure, 25 a, 78 6, c, d, 79 g
percolation, 47 6', 60 a, 65 a
thickness, 79 j
age, 61 c, 78 6, 79 j
tanks, 33 a, 57 a

EXTERNAL INFEUEXCES.
Electrolysis ; 75 a, 91 a
Sunshine ;

permeability, 47 e
Air;

corrosion, 59 a, b

shrinkage and expansion, 73 a
steam and carbonic acid;

corrosion, 40 a, 6
Water ; 4 b, 8 /

shrinkage & expansion, 73 a

limestone cone, 69 a, 6

hardness of mortar, 37 c

strgth, 23 a

adhesion, 26 a, 37 c

corrosion, 26 a, 37 c, 59 a, 6
sea ; 7 a, 31 a, 6, c, 49 a, 90 a

corrosion, 59 a, b

fineness of sand, 8 g

placing in, 4 c, 31 a, 6
Pressure ;

permeability, 78 6, c, d, 79 g
Percolation ;

permeability, 8/, 476, 60 a
Sewage; 37 c
Oil ; 53 a to /, 63 a to c, 68 a, b

Heat and Cold.
Freezing- weather;

mixing, 44 a; placing, 44 a
finished work, 19 a, 44 a, 90 a
Expansion coefficient; 1 a, 10 a
Thermal conductivity; 46 //,

70 g, i

Fire ; 41 a-e, 46 a-e, 70 a-i
San Francisco, 71 a-d
aggregate, 41 c, d, e
gravel arid broken stone, 41 c
cinders, 41 e
disintegration, 70 d-f
strgth, 46 d, 70 d-f
elastic properties, 70 c
requirements, 46 e
reinforced cone, 41 6, 46 c, e, 70 h

COL.UMNS.
Columns ;

clay in cone for , 92 a
strgth of ; 35 a
elastic modulus ; 35 a



DIRECTORY TO EXPERIMENTS.



1139



Directory to Experiments, pp 1140-1183.



REINFORCEMENT, METALS,

Concrete, reinforced ;

shear, 81 6, h
stresses in , 81 g, h
fire, 41 6, 46 e
Reinforcement ;

strgth, 81 h
fire, 46 c

permeability, 47 g
adhesion A friction : 64 a, 6,

81 d, h, 88 a
plain & deformed bars, 64 a,

74 a

high & medium steel, 88 a
disturbance, 64 a, 76 d
proportions,- 64 6
time, 26 d
elastic limit, 88 a



ADHESION, CORROSION.

fatigue, 76 d

exposure, 26 a, 37 a, 6, c
corrosion of ; 2 b, 26 a, 6, c,

37 a, 6, c, 40 a, 6, 44 c, 47 I,

54 a, 59 a, 6

conductivity of ; 70 i
electrolysis ; 75 a, 91 a
disturbance of ; 47 /, 64 a.

76 d
plain fe deformed ;

adhesion, 64 a, 74 a
li i^-Ii V medium steel ;

adhesion, 88 a
percentage of ; 81 g
strength of; 81 h
stirrups ; 81 h



1140



CONCRETE.



Experiment and Practice*
Selected Results.

See Directory, pp 1135, etc.
Order of arrangement.

The features entering into the manufacture and behavior of concrete are
so numerous, and in the reports of experiments, etc, they are unavoidably
so interlaced, that it has been found impracticable to group the several items
in the body of the text in satisfactory order below.

Most of our "selected results" are therefore here placed approx in the order
of their dates of publication, and furnisht with a directory, pp 1135 etc, by
means of which any particular subject may be promptly found. The direc-
tory is arranged rationally (i e, not alphabetically); and, as far as practi-
cable, in the order followed in the text (pp 930-947 k, 1084-1134), referring
to cement, sand, mortar, aggregate and concrete, plain and reinforced.
The items, covered by any one publisht statement, are given a common
number, and, under this common number, the several paragraphs are indi-
cated by letters. These letters usually distinguish also betw the several
features covered by the common number.

Thus, under Expt 8, we have a number of conclusions reached by R.
Feret: under 8 a, conclusions respecting strength of mortar as affected by
proportion of cement and fineness of sand; under 8 c, conclusions respecting
porosity and permeability as affected by fineness of sand and richness of
mortar, etc, etc.

In the directory, semicolons, in general, are used to distinguish between two
different but related ideas. Thus: "Strength; fineness of sand" and
* 4 Sand, fineness of ; strength," refer to items giving information re-
specting the effect of fineness of sand upon strength of mortar or cone.



1. Bounicean, Annales des Fonts et Chaussees, 1863, p 181.
1 a. Expansion Coefficient.

Bar iron 0.000 0123 5 per deg C; 0.000 006 86 per deg F

Port cem cone 0.00001370 " " " 0.00000760 '



2. John C. Traiitwine, Civil Engr's Pocket Book, 1872.

2 a. Sand, density; moisture, compacting.

Specimens. Ordinary pure sand from the seashore, both dry and moist
(not wet), see table. Sand B was of much finer grain than A. C consisted
of the finest grains sifted from B.

Treatment. The dry sands were compacted by thoro shaking and jar-
ring; the moist sands by ramming in thin layers.

Results.

Sand A Sand B Sand C

(coarse) (finer) (finest)



Dry



Moist



Dry



Moist



Dry



Loose 97 59

Compacted 112 68



Increase... 15



Ibs Solid Void Ibs Ibs Solid Void Ibs Ibs. Solid Void

per % % per per % % per per % %

cu cu cu cu cu

ft ft ft ft ft

41 86 88 53.4 46.6 69 82 50 50

32 107.5 101.6 61.6 38.4 103.5 98.5 60 40

9 21.5 13.6 8.2 8.2 34.5 16.5 10 10



9



Percent... 15.5 15.2 22 25 15.5 15.3 17.6 50 20.1 20 20

2 b. Corrosion. 10 years' trial. Dampness absolutely excluded after
setting. Cements protect iron, lead, zinc, copper, brass. Plaster
of Paris protects all these except ungalvanized iron.



EXPERIMENT AND PRACTICE. 1141

For abbreviations, symbols and references, see p 947 1.

3. John Watt Saudeman. last C E, Vol. liv, 1878, p 260.

3 a. Aggregates ; density.

Results Ibsper Percentage

No. cub ft of voids

1. Broken limestone, mostly 3 inch 95 50.9

2. Screened gravel, from small pebbles to 2.5 inch. . Ill H 33.6

3. Equal parts of Nos. 1 and 2, well mixed 113 1 A 34.0

4. Broken sandstone, 4 to 8 inch 74 50.0

5. " " from sand to 4 inch 92 34.0

6. Equal parts of Nos. 4 and 5, mixed 91 M 36.0

4

4. Eliot C. Clarice, A S C E Trans, Apr, '85, Vol 14, p 163. Expts
for Boston Main Drainage Works.

Results.

4 a. Clay. The addition of not exceeding one part of clay to 2 of cem,
gave a "much more dense, plastic and water-tight paste, convenient
for plastering surfaces or stopping leaky joints," and, in general, had no
markt effect upon the strength of Portland and natural cem. Mortars,
made with sand containing 10% of loam, were of normal strgth at 6 and 12
mos, tho of only about half normal strgth up to 1 mo. Clay, in cem, is "an
almost impalpable powder, with particles fine enough to fill the spaces be-
tween the particles of cem."

4 b. A year's saturation in fresh or salt water, and in contact with
oak, hard pine, white pine, spruce or ash, did not affect the
mortars.

4 c. Salt, either in the water used for mixing, or in that in which the cem
is laid, retards setting somewhat, but has no important effect upon the
strength.

4 d. Consistency. Excess of water retards setting. Sfat cems
need more water than Port ; fine-ground more than coarse; quick-
setting more than slow.

4 e. The finer the sand, the less the strength.

4 f. With sand, fine-ground cems are strongest; coarse-ground
are strongest neat, especially with Portlands.

4 g. Port resisted abrasion best when mixt with 2 parts sand; nat with
1 part. Resistance diminished rapidly with slight variations from these
proportions.

4 h. In setting, mortars expand > 1 part in 1000.

5

5. Allen Hazen, Mass. State Board of Health, Report '92, p 550.
Sharp-grained sand.

5 a. Uniformity coefficient (u. c.) p 947: <2 <3 6 to 8
Voids, per cent, approx 45 40 30

6

6. E. Carey, Inst C E Procs, Vol 107, '92, p 55.

6 a. Sulfuric acid ; strength. Neat cem, gaged with water con-
taining 5 % acid, had, at 7 days, only 27 % of the strength of neat cem
gaged with water free from acid.

L W T

7. Dr. Wilhelm Michael is. Inst C E Procs, Vol 107, '92, pp 372, 375.

7 a. Disintegration of porous cem in sea water shown to be
due to the action of sulfuric and hydrochloric (muriatic) acids, contained in
the magnesium sulfates and chlorides of sea water. These acids leave the
weaker base, magnesium (which is deposited as a hydrate), and combine
with the lime of the cem, expanding and disintegrating the cone.



1142



CONCRETE.



For Directory to Experiments, see pp 1135-9.

8

8. R. Feret. Annales des Fonts et Chaussees, 7e serie, Tome IV, '92.

8 a. Results. Strength of mortar increases with proportion of cem,
and, in general (especially at the beginning of hardening) with size of sand.

8 b. Mortars vary widely as to porosity. Compare 9 d, 9 e.

8 ic. Porosity increases 8 <l. Permeability increases

with fineness of sand, with coarseness of sand,

with richness of mortar with richness of mortar.

8 e. Mortars made with a mixture of coarse and line sands are less
porous and less permeable than others.

8 f. The permeability of mortars subjected to continuous percola-
tion of fresh or sea water, diminishes rapidly; but, in certain cases,
the mortar disintegrates or cracks.

8 g. To avoid disintegration in sea water, use coarse sand and plenty
of cem. Mix wet.

8 h. Density of sand ; moisture and tamping. Fig. 1.



0.500



0.400



^ 0.300



0.000



0.04



0.08



0.12



0.16



}Fer



utiler



0.500



0.400



0.300



0.000



0.04 0.08 0.12 0.16

Po unds of Water per pound of dry sand.

Fig 1. Moisture and Tamping.

M. Feret used (1) a very fine dune sand and (2) a coarser sea sand. Wm.
B. Fuller, E N, '02, Jul 31, p 81, used a bank sand, (1) loose and (2) tamped.

From these results, it appears that the addition of water affects the vol
of the sand* in two opposite ways; (1) by insinuating itself betw the sand
particles, thus increasing the vol for a given wt; (2) by decreasing the fric-
tion between the grains, allowing them more readily to take up the positions
of closest contact, and thus diminishing the vol. When only small vols of
water have been added, the first of these effects seems to prevail, the bulk
increasing until the vol of water reaches from 2 to 5 % of the vol of dry sand.*
With more water, the lubricating effect prevails, the vol diminishing.



Loose



Tamped



10 20



30



40 50



60 70



90 100



10 20 30 40 50 60 70 80 90
Percentage of solid in given volume ofaan&

Fig 2. Compacting.

8 i. Shape of grain and tamping. Fig. 2.
* See foot-note *, p 946.



100



EXPERIMENT AND PRACTICE.



1143



abbreviations, symbols and references, see p 947Z.

Specimens. Four materials, as follows:

a. Granitic sand, rounded grains; c. Broken shells, flat grains;

6. Ground quartzite, angular grains; d. Residue from 6, lamellar grains.
Each of the four materials screened to the same granulometric composi-
tion, viz: c, 0.5; m, 0.3; /, 0.2.f (See p 946.)
Results. See Fig. 2.
8j. Effect of size of grain. Fig. 3.







150 200

i per linear decimeter.

Fig 3. Size and Density.

Theoretically, the density, in a sand* or gravel,* composed of grains of
uniform size, should be independent of the absolute size (11 30, p 947 6); but
experimenters have obtained contradictory results, showing unimportant
variations of density with size. Thus (T & T, p 170), if sand (except very
fine sizes, such as pass a sieve with 74 meshes per linear inch) and broken
stone, with irregular particles of approx uniform shape, be separated into
portions containing particles of unif9rm size, these several portions will
show approx equal percentages of voids. This agrees with R. Feret's ex-
periments (T & T, pp 171 and 142), Fig 3, according to which each of the 3
sizes (coarse, medium and finef) contained 50 % voids. M. Feret's results
are represented by the hor line in Fig 3. On the other hand (Fig 3) M.
Candlot (Feret, Ann des Fonts et Chaussees, 1892, 2e sem) found the voids
increasing continuously, and M. Alexandra (ibid) found them first increasing
and afterward decreasing as the size grew smaller.

8 k. Effect of sizes of grains, and shaking or tamping.
L,oose sand* shows densities ranging from 0.525 to 0.610, the max density
occurring when 60 % of coarse sandf is mixed with 40 % of fine sand, with-
out medium sand. In sand shaken to refusal, the densities range
from 0.600 to 0.793, the max density occurring with a mixture of 55 % coarse
with 45 % fine; no medium.



* See foot-note *, p 946.

t Classification of sizes.

Passed Retained on

c. Coarse 20 60

m. Medium 60 180

/. Fine 180



meshes per lineal decimeter.



1144 CONCRETE.

For Directory to Experiments, see pp 1135-9.

8 1. Densities of loose unscreened sands and gravels:
shapes and sizes of grains; moisture.





Wt of
pebbles
con-
tained,

%


Mechanical Analysis
of sand proper


Dry

sand
Kg per
cu M.


Moist sand


Mois-
ture

%


Kg

per
cu M.


Coarse


Med.


Fine


Granitic
rounded grains . .
Schistose


1.0
25.4
6.6


0.136
0.359
0.259


0.723
0.293
0.412


0.141
0.348
0.329


1,586
1,753
1,600


0.8
1.2
1.8


1,495
1,650
1,332





9. Ltiigi Imiggi and Valentino Cardi, "Eaperimenti sulle Calci,
c;" Gemo Civile, Rome, '93.

Twelve years' expts



etc

Porosity, permeability, etc. Safe loads.
in connection with harbor works at Genoa, Italy.



Results.

9 a. In mortar, voids are due partly to air adhering to particles of
sand and agg, partly to evaporation of the water used in mixing.

9 b. In mortar, volume Of voids may vary from 12 to 46 % of vol of
mortar.

9 c. Minimum voids (5 %) in cone formed with 700 Ibs Port cem,
1 cu yd mixt sand, 1 M cu yds small gravel.

9 d. Porosity increases 9 e. Permeability increases

with fineness of sand; with coarseness of sand;

" richness of mortar; " poorness of mortar;

greatest with neat cem. least with neat cem.

Compare 8 c, 8 d.

9 f. Concrete of 1150 Ibs Port cem, 1 cu yd mixt sand, 1 M cu yds small
gravel, carefully mixt with just enough water (about % cu yd) to work it
up, was impermeable under 40 ft head (17.3 Ibs/Q").

9 g. Concrete of 700 Ibs Port cem, 1 cu yd mixt sand, 1 M cu yds small
gravel, made into a hollow cyl with shell 2^" thick, was impermeable



ft head (5.64 Ibs/Q") and barely permeable under 27 ft (11.7
Similar cyls, of same mixture, without the gravel, leaked



under 13
Ibs/Q").
somewhat under 13 ft and easily under 27 ft.

9 h. Safe load in compression. In the floors of the graving
docks, 1:2:3 cone of Port cem, sand and small gravel, safely carries 107
Ibs/Q" ; safety factor, 15.

- 10 -
10. I>r. Keller, Thonindustriezeitung '94, No. 24.

10 a. Expansion Coefficient. Temps from 16 to + 72 C =
+ 3 to + 162 F. Gravel (20 mm) and sand, in equal parts.

Mixture of sand and gravel, parts

Proportions (1 part cem) to 48

Coefficient, per degree C... 0.000 01 2 6 0.0000101 0.0000104 0.0000095
" F... 0.0000070 0.0000056 0.0000058 0.0000053



11

11. Oeo. W. Rafter, 2d Report on Genesee R Storage Project, '94.
See E R, '06, Jan 27, p 109.

11 a. Concrete with hard sandstone, gave strength 50 % greater
than where shale was substituted.



EXPERIMENT AND PRACTICE. 1145

For abbreviations, symbols and references, see p 9472.

12

12. Leibbrand. ER,'94,Nov3.

12 a. Comp strength ; age. Bridge over Danube at Mnnder-
kingen. Cone 1 : 2.5 : 5, wet. Cubes 20 cm (8").

Very thoroly mixt in an iron cylinder revolving on, a hor axis and con-
taining 40 steel balls weighing together 660 Ibs. Mixt 2 mins dry, 3 nuns wet.

Age in days 7 28 150 970 3285 (- 9 years)

Compstrgth.kg/sqcm.. 202 254 332 520 570

Ibs/sq in 2870 3610 4720 7400 8100

12 b. Max existing pressures, in bridge, 500 to 560 Ibs/Q".

13

13. J. Watt Sandeman, Inst C E Procs, Vol 121, '95, p 220.

13 a. Watertight concrete walls (pres not stated) made with

1 part cem leaving 10 % 9n No. 120 sieve,

2 parts sand with 27 % voids,

4.5 " large and small gravel with > 35 % voids.

13 b. Where agg has 35 % voids, vol of mortar should be 50 % of
vol of agg.

14

14. A. W. Dow, U. S. Inspector of Asphalt and Cem. Report of Engr
Commsr, Dist of Columbia, '97, p 165.

14 a. Compressive strength.

Specimens, 12-inch cone cubes, dry; rammed in cast iron molds;
thoroly wet twice daily.

The results for one year are means of five cubes ; the rest are means of two
cubes. Deduct from 3 to 8 per cent, for friction of press.

The materials were as follows:

Cement. Portland Natural

Per cent, retained on sieve of 100 meshes per linear inch, 8.5 14

Time for initial set, minutes 190 20

" " hard " " 305 36

Tensile strength as follows, Ibs. per square inch:

1 Day. 7 Days. 1 Mo. 3 Mos. 6 Mos. 1 Year.

Portland, neat 441 839

3 parts stan-
dard broken quartz, 248 429 398 428 474

Natural, neat, 96 180

" 2 parts stan-
dard broken quartz, 91 188 327 414 485

Sand used in concrete.

No residue on a No. 3 sieve; 0.5 per cent, passed No. 100. Voids 44 per
cent., with 4.4 per cent, water.

Broken Stone. Gneiss. Of Nos. 6 and 12 (table below) 3 per cent,
retained on 2.5 inch mesh; all on li inch. Others, retained on 2.5 inch;
nearly all on 0.1 inch. For voids, see table, below.

Gravel. Clean quartz, passing a 1 1-inch mesh, 2 per cent, passing a No.
10 mesh. Voids, 29 per cent.

Water. With Portland cement, 0.09 cu. ft. ( = 5.7 Ibs.) per cu. ft. of
rammed concrete; with natural cement, 0.12 cu. ft. ( = 7.5 Ibs.).

For Results, see p 1146.



1146 CONCRETE.

For Directory to Experiments, see pp 1135-9.

Crushing Strength of 12 in. Concrete Cubes, in Ibs. per sq. in,

Experiments by A. W. Dow, as above:
Parts by volume ; cement, 1; sand, 2; aggregate, 6.





Aggregate


Voids in Aggregate.


Crushing Strength,
Ibs. per sq. in., after


No.


02 5

I 1


!


Per
Cent,
of Vol.


Mortar,
in
percentage
of Voids.


10
Days.


45
Days.


3

Mos.


6
Mos.


1

Year.




ft


o
















- 7


6




45.3


83.9


908


1790


2260


2510


3060


B 8


3


3


35.5


107.0


950


1850




2070


2750


1 9


4


2


37.8


100.6








. .


2840


| 10


6




39.5


96.2






:


<


2700






6


29.3


129.1


694


1630


2680


1840


2820


* 12


6




45.7


83.9


..


..


1630


1530


1850


1


6




45.3


83.9


228


539


375


795


915


3 2


3


3*


35.5


107.0


108


364


593


632


841


3 3


4


2


37.8


100.6










915


"S 4


6




39.5


96.2










800


5? 5




6


29.3


129.1


87


421


361


344


763


" 6


6




45.7


83.9






596




829



15

15. Tests of Metals, '98, p 572.

15 a. Cinder Cone with Port coin; ult comp strength.

Specimens; 12-inch cubes; water 10 to 12^ Ibs per cu ft of cone.
Results ;



Proportions by volume:



Cement



Sand
1
1
2
2
2
2
2
2
I
8



Cinders
3
3
3
3
4
4



Age, days No. of tests Lbs/sq inch



90
39
102
38
98

30-38
90-99
29
91

16 -



1541
2053
1098
1634

904
1325

724
1094

529

788



16. Considere, G6nie Civil, '99.
16 a. Ductility.
Specimens and results;

Cone cantilevers, 1 : 3, 6 cm sq, 60 cm long, tension side reinfd by 3
round iron bars 4M mm diam.

Treatment. Loading such that bendg mom was the same for all
cross sees. In one of the prisms, load increased until unit stretch = 0.002.
Then loads, = 44 to 71 % of this original load, were applied 139,000 times;
stress returning to each time.

Results. Unit stretches, 0.000545 to 0.00125; strgth but little
reduced. Similar tests of unreinfd specimens gave unit stretch, at rupture,
only 0.0001 to 0.0002; the reinforcement apparently enabling the cone to
endure far greater deformation than when not reinfd. But see Expts 36, 38.



EXPERIMENT AND PRACTICE.



1147



For abbreviations, symbols and references, see p 9472.

17

17. . E. Fowler, A S C E, Trans, '99, Vol 42, p 117.
17 a. Results. Proportions, assuming that

1 bbl Portland cem = 3.8 cu ft.

34 cu yds concrete = abt 27 cu yds after ramming.
Those cones, for which the vols of stone appear in bold-face type (as l.OO),
have their voids filled or more than filled; while, in those printed in plain
type (as 1.04), the voids are not filled and the cone is porous and deficient
in strgth.

Quantities in 1 cu. yard of concrete:

Stone with Stone with

Cement, Sand, 40 % voids, 50 % voids,

Proportions Barrels cu yds cu yds cu yds

2:3 1.77 0.51 O.87 .05

2. 4 1.59 0.47 0.95 .15

25 1.39 0.42 1.04 .26

34 1.30 0.57 O.83 l.OO

35 1.16 0.52 O.92 .11
136 1.04 0.48 l.OO .20
146 1.00 0.55 O.91 .09
1 4 7 0.92 0.51 0.97 1.17
1 4 8 0.83 0.47 1.03 1.25

The foregoing figures agreed well with the results of practice. The column
for stone with 40 % voids closely represents broken limestone, which breaks
into pieces of various sizes; while the column with 50 % voids represents
trap rock, which breaks into pieces of more nearly uniform size.

18

18. Tests of Metals, '99.

18a. Compressive Strength of 12" cubes of dry Portland ce-
ment concrete, for Geo. A. Kimball, Chief Engr Boston El Ry Co.
Specimens ;

Sand. Coarse, clean, sharp. Voids, measd loose and moist, 33 % ;
measd after settling by saturation with water, 25 %.

Stone. Conglomerate from Roxbury, Mass. Voids, measd loose, 49.5 %.

4.8 % passed 2 1 A" ring, caught on 2" ring ;
76.7 % " 2" " , " I" " ;

18 % " r " , " %" " ;
0.5 % " 1 A" " .

Treatment. Mixt by hand. "Water barely showed after ramming.
Cubes, except those tested at 7 days, buried in wet ground until within
one wk of testing. In general, 5 cubes of each mix of each brand were


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