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Full text of "Voids, settlement and weight of crushed stone"

135 
v.23 



UC-NRLF 



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LIBRARY 

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UNIVERSITY OF CALIFORNIA. 

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Class 



UNIVERSITY OF ILLINOIS BULLETIN 



Vol. V. 



MAY 6, 1908 



No. 23 



[Entered Feb. 14, 1902, at Urbana, 111., as second-class matter under Act of Congress 

July 18, 1894] 



BULLETIN NO. 23 

VOIDS, SETTLEMENT AND WEIGHT OF 
CRUSHED STONE 



BY 



IRA O. BAKER 




UNIVERSITY OF ILLINOIS 
ENGINEERING EXPERIMENT STATION 



URBANA, ILLINOIS 

PUBLISHED BY THE UNIVERSITY 





HE Engineering Experiment Station was established by 
action of the Board of Trustees December 8, 1903. It is 
the purpose of the Station to carry on investigations 
along various lines of engineering and to study problems 
of importance to professional engineers and to the manu- 
facturing, railway, mining, constructional, and industrial interests 
of the state. 

The control of the Engineering Experiment Station is vested 
in the heads of the several departments of the College of En- 
gineering. These constitute the Station Staff, and with the Di- 
rector, determine the character of the investigations to be under- 
taken. The work is carried on under the supervision of the Staff; 
sometimes by a research fellow as graduate work, sometimes by 
a member of the instructional force of the College of Engineer- 
ing, but more frequently by an investigator belonging to the. 
Station corps. 

The results of these investigations are published in the 
form of bulletins, which will record mostly the experiments of the 
Station's own staff of investigators. There will also be issued 
from time to time in the form of circulars, compilations giving 
the results of the experiments of engineers, industrial works, 
technical institutions, and governmental testing departments. 

The volume and number at the top of the title page of the 
cover are merely arbitrary numbers and refer to the general publi- 
cations of the University of Illinois; above the title is given the 
number of the Engineering Experiment Station bulletin or circular. 
which should be used in referring to these publications. 

For copies of bulletins, circulars or other information, 
address the Engineering Experiment Station, Urbana, Illinois. 




UNIVERSITY OF ILLINOIS 
ENGINEERING EXPERIMENT STATION 

BULLETIN No. 23 MAY 1908 

VOIDS, SETTLEMENT AND WEIGHT OF 
CRUSHED STONE 

BY IRA O. BAKER, PROFESSOR OF CIVIL ENGINEERING 

INTRODUCTION 

Crushed stone has become an important material of construc- 
tion in modern engineering work. The chief causes for this are 
the great increase in the use of plain and reinforced concrete, 
and the increased activity in macadam road construction. The 
advances made in these lines have been so rapid that crushed 
stone has suddenly changed from a minor material to one of first 
importance in modern engineering construction. This has been 
done in such a short time that the present knowledge of the prop- 
erties of crushed stone is entirely inadequate; and the determin- 
ation of its weight, voids, and settlement, and the variations of 
these have never been attempted on any adequate scale, so far 
as the writer has been able to ascertain. Before commencing this 
article a diligent search was made of engineering literature for 
information upon this subject. No definite information was found 
concerning the weight of a cubic yard of stone of different sizes 
(except one item as noted in Appendix I) or the amount of settle- 
ment in transit. The only other reference on the subject was the 
request of a correspondent in one of the leading engineering 
journals for information regarding the weight of crushed stone. 
In answer a wide range of limits was given with the explanation 
that as no definite values were known, the general practice was to 
assume some value within these limits. 



169957 



2 ILLINOIS ENGINEERING EXPERIMENT STATION 

The need for reliable data on these subjects is very apparent 
to the engineer who makes designs and estimates. Accustomed 
to use all other materials, both of engineering and everyday life, 
and to deal with standard units of weights and measures, he finds 
here that there are no standards at all. For instance, practically 
all of the quarries sell stone by the yard, but the so-called yard 
in one place is not always the same as the yard at some other 
place. In most cases a certain weight is taken as a yard; but 
these weights are generally arbitrary amounts that are supposed 
to approximate the true value, and they differ for different locali- 
ties and for the different kinds and sizes of stone. Consequently, 
the number of yards and therefore the cost of the stone for the 
same piece of work would differ according to the location of the 
stone supply. Furthermore, this ambiguity may cause difficulties 
to arise between the producer, the carrier, and the consumer. 
The producer measures the volume loose in the car after it is 
loaded from the crusher. The railway then weighs the cars and 
computes the number of cubic yards by assuming the weight of a 
yard. The consumer receives the invoice from the producer, and 
the freight bill from the railway, and tries to check them, but 
generally finds they do not agree. So it is evident that this lack 
of standards entails possibilities of constant controversy between 
the shipper, the railroad, and the consumer. 

Again, it is well known that the volume of crushed stone 
shrinks in transit; and to make accurate estimates the engineer 
should know the probable amount of this shrinkage. If a cer- 
tain number of yards of tamped or consolidated stone are required 
for a pier or for a certain length of macadam road, it is neces- 
sary to know how many yards to order at the quarry so as to 
have the required amount in the structure. As done at present, 
the engineer to be on the safe side usually orders considerably 
more than he thinks is enough, and even then he sometimes finds 
he has not made allowance enough. 

In order to establish a definite standard for the different sizes 
and varieties of crushed stone, tests should be made until suffi- 
cient data have been accumulated to determine a definite value for 
the weight of a cubic yard of crushed stone under various condi- 
tions, or to establish a coefficient by which either the weight of a 



BAKER WEIGHT OP CRUSHED STONE 3 

cubic foot or a cubic yard of the solid stone, or its specific grav- 
ity, can be multiplied to give the weight per cubic yard of crushed 
stone. It is obvious that to make the results of the greatest 
value will require a very large number of observations under 
a variety of conditions. It is the purpose of this article to give 
the results of a few tests along these lines. 

Of the data hereinafter referred to, the observations on Ches- 
ter stone and part of those on Joliet stone were made by Mr. Albert 
J. Schafmayer, a senior student in Civil Engineering, during the 
summer of 1906, while employed by the Illinois Highway Com- 
mission in connection with constructional work. A brief sum- 
mary of Mr. Shafmayer's results was published in the report 
of A. N. Johnson, State Highway Engineer, in the first annual 
report of the Illinois Highway Commission. The observations on 
Kankakee stone and part of those on Joliet stone were made 
by Mr. Benjamin L. Bowling, an employee of the Engineering 
Experiment Station, during the fall of 1907. None of the inves- 
tigations could have been made except for the generous cooper- 
ation of the officials of the State Penitentiaries at Chester and 
Joliet, and of the McLaughlin-Mateer Company of Kankakee. 

Some observations were taken at Chicago and at Gary, Illinois, 
but unavoidable conditions at these plants prevented a completion 
of the work, and the results obtained are too incomplete to be of 
any considerable value, and hence are not further referred to. 

THE STONE 

The observations referred to in this article relate wholly to 
limestone, although in the appendix some data are given con- 
cerning trap. The limestones experimented with were those quar- 
ried at Chester, Joliet, and Kankakee. 

The Chester stone is a rather coarsely granulated gray lime- 
stone of the lower carboniferous group, and is quarried in the 
grounds of the State Penitentiary at Chester, on the Mississippi 
River, about half way between St. Louis and Cairo. 

The Joliet stone is a compact, fine-grained magnesian lime- 
stone of the Niagara series, and is quarried in the grounds of the 
State Penitentiary at Joliet, about 40 miles southwest of Chicago. 
The output of the crusher consists of 28 per cent 3-in. stone, 53 
per cent 2-in., and 17 per cent Hn. 



4 ILLINOIS ENGINEERING EXPERIMENT STATION 

The Kankakee stone is a coarse-grained argillaceous lime- 
stone of the Niagara group, and is quarried at Kankakee, on the 
Kankakee River, about 55 miles south of Chicago. 

DIVISIONS OF THE SUBJECT 

The subject will be considered under the following heads: 
I. Specific gravity; II. Absorptive power; III. Percentage of voids; 
IV. Settlement in transit; V. Weight per cubic yard; VI. Coefficients 
for determining the weight of crushed stone. 

I. SPECIFIC GRAVITY 

A knowledge of the specific gravity of a stone is useful in 
determining the per cent of voids in broken stone; and the easi- 
est way to determine the weight of a cubic unit of solid stone is 
to find its specific gravity. 

Wa 

Specific gravity ~- Wa _ Ww 

in which Wa is the weight of a fragment weighed in air, Ww the 
weight of the same fragment suspended in water. If the 
stone is porous to any considerable extent, the weight 
in water should be determined so quickly that the absorption dur- 
ing the weighing will be inappreciable. 

Samples of stone were collected from the various parts of the 
Joliet, the Kankakee, and the Chester quarries which were being 
worked to produce the broken stone considered in the later parts 
of this paper. The values of the specific gravity are given in 

Table 1. 

II. ABSORPTIVE POWER 

A knowledge of the amount of water absorbed by a stone is 
useful in determining the voids by the method of pouring 
in water, and is also useful in correcting the weight of wet stone. 

The absorption was determined by thoroughly drying a speci- 
men, weighing it, immersing it in water for 96 hours, drying 
with blotting paper, and weighing. The results are given in 
Table 2. 

III. PERCENTAGE OF VOIDS 

The per cent of voids in broken stone of different sizes has an 
important bearing upon the amount of cement and sand required 



BAKER WEIGHT OF CRUSHED STONE 



TABLE 1 
SPECIFIC GRAVITY OF LIMESTONE 



Ref. 
No. 


Location 
of 
Quarry 


Specific 
Gravity 


Observer 


Position in Quarry 


1 


Joliet- 


2.77 


Schafmayer 


Near Center. 4 to 6 ft. deep 


2 


" 


2.78 


" 


it ti it it 


3 


" 


2.70 


tt 


25 ft. W. of C., 4 ft. to 6 ft. 










deep 


4 


11 


2.69 


1 1 


n i t 


5 


a 


2.72 


1 1 


E. 


6 


" 


2.74 


it 


it i i 


7 


tt 


2.71 


a 


N. 


8 


n 


2.70 


1 1 


U ( - ( 


9 


" 


2.63 


tt 


S. " ' 




Mean 


2.71 






10 


Joliet 


2.74 


Bowling 


25 ft. S. of C. of floor 30^ft. 










deep 


11 


" 


2.68 


" 


u tt u 


12 


it 


2.74 


tt 


At ' 


13 


" 


2.73 


1 1 


<( i 11 


14 


" 


2.69 


tt 


25 ft. N. 


15 


" 


2.70 


a 


it it t it 




Mean 


2.71 






16 
17 


Chester 


2.67 

2.58 


Schafmayer 


N. end over 25 ft. deep 
50 ft. S. of the preceding, 
over 25 ft. deep 


18 


u 


2.59 


1 1 


100" " " " 


19 


tt 


2.49 


n 


Center near top 


20 


" 


2.66 


a 


N. end " " 


21 


tt 


2.50 


' 


., .- It 


22 


It 


2.48 


tt 


Center " " 




Mean 


2.57 






23 


Kankakee 


2.62 


Bowling 


S. end at top 


24 


" 


2.64 


tt 


U It It 


25 





2.65 


it 


20 ft. deep 


26 


u 


2.65 


1 1 


u ti 


27 


It 


2.56 


*' 


40 ft. " 


28 


It 


2.56 


14 


u u 


29 


tt 


2.60 


U 


N. at floor 


30 


tt 


2.62 


u 


a tin 




Mean 


2.61 







6 



ILLINOIS ENGINEERING EXPERIMENT STATION 



in making concrete; and the per cent of voids in connection with 
the weight of a unit of solid stone is useful in determining the 
weight of a unit of volume of broken stone. 

The percentage of voids may be determined in either of two 
ways: (1) by pouring in water; and (2) by computation from the 
specific gravity and the weight of a volume of broken stone. 

1. By Pouring in Water. Determine the weight of water a 
given vessel will contain, then fill the vessel with broken stone, 
and determine the weight of water that can be poured into the 

TABLE 2 
ABSORPTIVE POWER OF LIMESTONE 



Ref. 
No. 


Kind 
of 

Stone 


Weight 
in Ib. 
per 
cu. ft. 


Absorption 


Position in Quarry 


Ib. per 
cu. ft. 


Per cent 
by 
Weight 


1 


Joliet 


170.66 


1.23 


0.72 


25 ft. S. of C. of the floor, 30 












ft. deep 


2 




166.98 


.79 


0.47 


(I U I 


3 




170.85 


.86 


0.50 


At Center ' 


4 




170.41 


1.25 


0.73 


tt . (, i 


5 




167.61 


1.13 


0.68 


25 ft. N. 


6 




168.60 


1.28 


0.76 


" " * 




Mean 


169.18 


1.09 


0.64 




7 


Kankakee 


163.49 


1.87 


1.14 


S. end at top 


8 




164.92 


1.98 


1.20 





9 




165.11 


2.66 


1.61 


" 20 ft. deep 


10 




165.30 


2.81 


1.70 


(( U (( 


11 




159.81 


4.49 


2.81 


" 40 ft " 


12 




159.68 


4.67 


2.92 


U tl 44 


13 




162.24 


2.99 


1.84 


N. at floor 


14 




163.73 


2.85 


1.74 


44 It <l 




Mean 


163.04 


3.04 


1.84 




15 


Chester 


167.0 


.69 


.31 




16 


4 4 


165.8 


1.22 


.74 




17 


" 


164.5 


1.89 


1.15 






" 


165.1 


1.34 


.81 




18 


" 


161.5 


2.54 


1.57 




19 


U 


161.5 


2.34 


1.45 






Mean 


164.2 


1.67 


1.01 





BAKER WEIGHT OF CRUSHED STONE 7 

interstices of the broken stone. The ratio of the first amount of 
water to the second is the proportion of voids. 

In this method three sources of error require consideration, 
(a). In pouring in the water, part of the contained air is not driv- 
en out; and therefore the resulting per cent of voids is too small. 
The error from this source may be reduced, if not entirely elimi- 
nated, by pouring the stone into the water; but this procedure 
introduces a new error, since the stone will not pack to the same 
degree as in the ordinary method of filling a vessel or bin with 
broken stone, and hence the result of pouring the stone into the 
water will also give too large a per cent of voids. (&). If the 
stone absorbs water during the test the apparent percent of voids 
will be too great, (c). If the vessel has a wide mouth, as almost 
necessarily it should have, there will be a likelihood of considerable 
error in telling when the vessel is exactly full of stone and also 
of water. The resulting error may make the per cent of voids 
either too large or too small. 

2. By Computation. Determine the weight of a known vol- 
ume of broken stone. Compute the weight of an equal volume 
of the solid stone by multiplying the known volume by the 
weight of an equal volume of water and by the specific gravity of 
the stone. The difference between the weight of the volume of 
solid stone and that of the broken stone is the weight of stone 
equal to the volume of the voids. The ratio of this weight to the 
weight of the given volume of broken stone is the proportion of 
voids. 

This method is subject to the error of determining when the 
vessel is exactly full of stone. In practice it is more complicated 
than the preceding method, but it is more exact. 

Table 3 gives the per cent of voids for three sizes of Chester 
limestone determined by the two methods referred to above, by 
two independent observers for different methods of filling the ves- 
sels with broken stone; and Tables 4 and 5 the same for Joliet and 
Kankakee limestone, respectively. In each case the results are 
corrected for the absorption of the stone. Precautions were tak- 
en also to eliminate absorption by the walls of the vessel used. 
The distance of drop employed in filling the vessel corresponded 
to that employed at the time in loading cars of broken stone. 



ILLINOIS ENGINEERING EXPERIMENT STATION 

TABLE 3 
PERCENTAGE OF VOIDS OF CHESTER LIMESTONE 



I 

H 
O 

6 


I 

cc 

H 

o 

1 


8 S 

A ~ 


1 

02 . 


If 


1. 


M 


Per Cent of Voids 


By Pour- 
ing in 
Water 


From 
Specific 
Gravity 


3 * 

o 


I 


3 


O 
$ 


> 






By Use of Vessel Containing 27 cu. ft. 




1 
2 
3 


f-in. Scr. 


15ft. drop 


2430 
2395 
2435 


3150 
3095 
3140 


720 

700 
705 


11.52 
11.20 
11.28 

Mean 


42.7 
41.5 
41.8 


43.9 
42.4 

43.8 


42.0 


43.4 


4 
5 


2 in.-f-in. 

u - 


15 ft. drop 

u 


2320 
2375 


3110 
3165 


790 
790 


12.64 
12.64 

Mean 


46.8 
46.8 


46.4 

45.8 


46.8 


46.1 


6 

7 


3 in.-2 in. 


15 ft. ^drop 


2370 
2390 


3160 
3185 


790 
795 


12.64 
12.72 

Mean 


46.8 
47.2 


45.3 

44.8 


47.0 


45.0 






By Use of Vessel Containing 2.6 cu. ft. 




8 
9 
10 


|-in. Scr. 

u 


Shoveled 

< i 


226.5 
227.0 
216.5 


293 
293 

283 


66.5 
66.0 
66.5 


1.06 
1.06 
1.06 

Mean 


41.0 
40.6 
41.0 


45.8 
45.7 

48.9 


40.9 


46.8 


11 
12 


f-in. Scr. 


it 


214.5 
210.5 


286 
284 


71.5 
73.5 


1.14 
1.17 

Mean 


44.0 
45.2 


48.6 
49.6 


44.6 


49.1 


13 


" 


20 ft. drop 


229.0 


293 


64.0 


1.025 


39.4 


45.2 


14 
15 


2 in.-f-in. 


Shoveled 
20 ft. drop 


204.0 
237.0 


286 
306 


82.0 
69.0 


1.31 
1.10 


50.5 
42.5 


51.2 
43.3 


16 
17 


3 in. -2 in. 


Shoveled 
20 ft. drop 


212.0 
245.0 


291 
313 


79.0 
68.0 


1.265 
1.09 


48.7 
41.8 


49.3 
41.3 



BAKER WEIGHT OF CRUSHED STONE 



TABLE 4 
PERCENTAGE OF VOIDS OF JOLTET LIMESTONE 



1 

H 
O 

I 


1 

GQ 

"o 
1 

2 


be 

'o -2 
"o 


o> 
a 

1 
$ 


5 

If 


eB 

O 1 "" 1 


* M r-j 

'o 


Per Cent of Voids 


By Pour- 
ing in 
Water 


From 
Specific 
Gravity 






By Use of Vessel Containing 2.34 cu. ft. 




1 

2 
3 


Hn. Scr. 



8 ft.^ drop 

u 


208.75 
208.75 
207.75 


270.75 
271.25 
270.25 


62.00 
62.50 
62.50 


0.99 
1.00 
1.00 

Mean 


42.3 
42.7 
42.7 


47.6 
47.6 
47.9 


42.6 


47.7 


4 
5 

6 

7 


2 in ; -Hn. 


8 ft. drop 


218.75 
221.75 
218.50 
220.00 


285.75 
288.50 
285.75 
286.75 


67.00 
66.75 
67.25 
66.75 


1.07 
1.07 
1.08 
1.07 

Mean 


45.8 
45.6 
45.9 
45.6 


45.1 
44.3 
45.1 

44.8 


45.7 


44.8 


8 
9 
10 
11 


3 in.-2 in. 


8 ft. drop 


227.25 
219.25 
222.25 

212.00 


291.75 

287.75 
290.25 

282.25 


64.50 
68.50 
68.00 
70.25 


1.03 
1.10 
1.09 
1.12 

Mean 


44.1 

46.8 
46.5 
48.0 


43.0 
45.0 
44.2 
46.8 


46.3 


44.7 


12 
13 
14 
15 


|-in. Scr. 


4 ft. drop 

u 
u 


215.75 

218.75 
209.25 
208.25 


276.00 
279.25 
273.00 
272.25 


60.25 
60.50 
63.75 
64.00 


0.96 
0.96 
1.02 
1.02 

Mean 


41.1 
41.3 
43.5 
43.7 


45.8 
45.1 
47.5 

47.7 


42.4 


46.5 


16 
17 

18 
19 
20 


2 in.-Hn. 

u 
(< 

t ( 


4 ft. drop 

it 

II 

u 


203.00 
209.75 
209.75 
212.25 
213.25 


277.25 

283.25 

282.75 
283.75 
284.00 


74.25 
73.50 
73.00 
71.50 
70.75 


1.19 
1.15 
1.17 
1.14 
1.13 

Mean 


50.7 
50.2 
49.9 

48.8 
48.3 


49.0 
47.4 
47.4 
46.7 
46.5 


49.6 


47.4 


21 


3 in. -2 in. 


4 ft. drop 


221.25 


291.25 


70.00 


1.12 


47.8 


44.5 






By Use of Vessel Containing 2.43 cu. ft. 




22 
23 
24 


3 in. -2 in. 

u 


4 ft. drop 

u 
u 


211.25 
216.25 
212.75 


287.75 
289.25 

285.75 


76.50 
73.00 
73.00 


1.22 
1.17 
1.17 

Mean 


50.4 
48.1 
48.1 


49.0 

47.7 
48.6 


48.6 


47.5 



10 ILLINOIS ENGINEERING EXPERIMENT STATION 

TABLE 5 
PERCENTAGE OF VOIDS OF KANKAKEE STONE 





0> 

H 

M 

o 



* 


<D 
1 

w 

8 
1 

33 


i 

Method 
of Filling 


! 

02 . 

MJQ 

0-* 




o 

G 1 -* 

Jl 

M 03 

^ 

^ 


M 

<D 

-1-3 
rt 

!s 

*0^ 

4J 

^ 


1. 

s *- 3 

t<~ 



^ 


Per Cent of Voids 


By Pour- 
ing in 
Water 


From 
Specific 
Gravity 






By Use of Vessel Containing 2.11 ou. ft. 




I 

2 
3 
4 


f-in. Scr. 

u 
( ( 
( ( 


8 ft. drop 
(( 

(i 

it 


189.50 
192.25 
186.00 
183.25 


242.75 
244.75 
237.50 
235.25 


53.25 
52.50 
51.50 
52.00 


0.85 
0.84 
0.82 
0.83 

Mean 


40.3 
39.7 
39.0 
39.3 


45.9 
45.1 
46.8 
47.6 


39.5 


46.4 


5 
6 


li-in.-f-in. 

u 


8 ft. drop 

a 


193.50 
197.50 


253.50 
258.00 


60.00 
60.50 


0.96 
0.97 

Mean 


45.4 

45.8 


44.7 
43.6 


45.6 


44.2 


7 
8 


2Hn.-li-m. 

u 


8 ft. drop 



196.50 
197.50 


258.50 

258.75 


62.00 
61.25 


0.99 

0.98 

Mean 


46.9 
46.4 


43.9 
43.6 


46.6 


43.8 


9 
10 


2i-in.-f-m. 

1 1 


8 ft. drop 

u 


202.25 
201.50 


260.50 
260.50 


58.25 
59.00 


0.93 
0.94 

Mean 


44.1 
44.6 


42.2 

42.4 


44.4 


42.3 






By Use of Vessel Containing 1.15 cu. ft. 




11 
12 


f-in. Scr. 



8 ft. drop 

u 


100.00 
103.75 


129.25 
132.75 


29.25 
29.00 


0.47 
0.46 

Mean 


40.9 
40.5 


47.5 
45.6 


40.7 


46.6 


13 
14 


IHn.-f-in. 

u 


8 ft. drop 



104.25 
104.50 


137.50 
136.75 


33.25 
32.25 


0.53 
0.52 

Mean 


46.5 
45.1 


45.4 
45.2 


45.8 


45.3 


15 
16 


2Hn.-f-in. 

i 1 


8 ft. drop 




106.50 
109.00 


138.25 
140.50 


31.75 
31.50 


0.51 
0.50 

Mean 


44.4 
44.0 


44.1 
42.8 


44.2 


43.5 



BAKER WEIGHT OF CRUSHED STONE 
TABLE 5 (Continued) 



11 



I 


o> 
c 
o 

43 


be 
1 1 


I 


0.0 

II 


(X> 

^ 


5 . 


Per cent of Voids 






o 


O 


i E 


<g 


-: 


*o^ 


o p 


By Pour- 


From 


6 


1 


^ M 


^ 


^ 


J 


. o 


ing in 


Specific 


__ 


53 




^ 


^g 


^ 


1 


Water 


Gravity 




By Use of Vessel Containing 0.694 cu. ft. 




17 


f-in. Scr. 


8 ft. drop 


63.00 


79.75 


16.75 


0.27 


38.5 


45.5 


18 




" 


63.50 


80.25 


16.75 


0.27 


38.5 


45.1 














Mean 


38.5 


45.3 


19 


2Hn.-li-m. 


8 ft. drop 


65.25 


85.25 


20.00 


0.32 


45.9 


43.6 


20 




< i 


66.50 


86.25 


19.75 


0.31 


45.4 


42.5 














Mean 


45.6 


43.0 



Precautions were taken to prevent absorption of water by 
fche sides of the vessel; and it is believed that there is no possi- 
bility of error from this source in the data given in Tables 3, 4, 
and 5. In some of the experiments the vessel containing the 
stone was hauled from the chute to the scales on a wagon; and to 
eliminate a possibility of error in weighing, the team was unhitched 
while the weight was being taken. 

Notice that the first part of Table 3 shows the percentage of 
voids for the different sizes of stone; while the second shows the 
variation due to the different methods used in filling the tub. An 
inspection of the table shows that with each vessel the voids in- 
crease with the size of the stone. It also shows that for both ves- 
sels the average percentages are fairly uniform, the greatest vari- 
ation being in the case of the 3-in. (3-in. to 2-in.) stone. In com- 
paring the tests in which the 15- and 20-ft. drops were used, the 
stone falling 20 feet invariably has a smaller percentage of voids 
than that falling only 15 feet. The lower part of the table shows 
that the voids were very materially less for the same size of stone 
when the tub was filled by the 20-ft. drop, than when the 
stone was shoveled in. These data show clearly that the density 
increases with the fall. However, the tests were not sufficient in 



12 



ILLINOIS ENGINEERING EXPERIMENT STATION 



number to justify an attempt to deduce a statement of the relation 
of the height of fall to the density of the mass. 

A comparison of the results in the last two columns of Table 

3 shows that for screenings the method by pouring in water gives 
a considerably smaller per cent of voids than by computation, 
while for the 2-in. (2-in. to f-in.) and the 3-in. (3-in. to 2-in.) 
sizes there is practically no difference by the two methods. Sub- 
stantially the same conclusions may be drawn from Tables 4 and 5. 

Summary of Voids: A summary of the results in Tables 3, 

4 and 5 is given in Table 6. 

TABLE 6 
SUMMARY OF PER CENT OF VOIDS 











Per Cent.of Voids 


Ref. 
No. 


Location 
of 
Quarry 


Size of Stone 




By Pour- 
ing in 
Water 


From 

Specific 
Gravity 


1 


Chester 


f in. Scr. 




40.9 


46.8 


2 


" 


f in. Scr. 




43.0 


45.6 


3 





2 in. to | 


in. 


46.6 


46.6 


4 


" 


3 in. to 2 


in. 


46.1 


45.1 


5 


Joliet 


| in. Scr. 




42.2 


47.1 


6 


" 


2 in. to | 


in. 


47.9 


46.2 


7 


" 


3 in. to 2 


in. 


47.5 


46.1 


8 


Kankakee 


f in. Scr. 




39.6 


46.1 


9 


" 


U in. to 


|in. 


45.7 


44.7 


10 


" 


2 in. to 


1 in. 


44.3 


42.9 


11 




2i in. to 


liin. 


46.2 


43.4 



IV. SETTLEMENT OF CRUSHED STONE IN TRANSIT 

Sometimes crushed stone is bought by bulk, in which case it 
may make a difference whether the volume is measured at the be- 
ginning or at the end of the journey. Therefore experiments 
were made to determine the settlement of crushed stone during 
transit in wagons and also in railway cars. 

Settlement in Wagons: Observations were first made to 
determine the relation between the settlement in wagons 
and the distance hauled. An attempt was made to de- 
termine the amount of settlement for regular increments 







BAKER WEIGHT OF CRUSHED STONE 



13 



in the distance hauled. This was done by stopping the 
team and taking a measurement each successive 100 feet until 
the settlement for that distance was too small to measure. The 
measurements in all cases were taken by using two straight 
edges, one placed across the top of the box and the other resting 
on the top of the stone. Then as both straight edges were of the 
same width, each measurement was taken from the top of the 
upper one to the top of the lower one. Measurements were taken 
near each side and on the center line, near the front, middle, and 
back of the load, making a total of nine measurements for each 
load. 

The data for Chester limestone are given in Table 7. The 
results vary surprisingly, for example, compare tests No. 2 and 
3, or 7 and 8, or 13 and 14. The haul was over about equal distances 
on macadam, cinders, and earth. The results were obtained 
within a day or two of each other, and it does not seem possible 
that the smoothness of the roads could have changed materially 
in the meantime. An attempt was made to drive equally care- 
fully every time. About the only safe conclusions that can be 
drawn from these data are: (l) about half of the settlement oc- 
curs in the first 100 feet; and (2) the settlement at half a mile is 
practically the same as that at a mile. 

TABLE 7 

EFFECT OF DISTANCE HAULED UPON SETTLEMENT IN WAGON 
Experiments on Chester Limestone by Mr. Schafmayer 



Test 
No.* 


Size of 
Stone 


Method of 
Loading 


Per Cent of Settlement for 
Hauls ef- 
fect 


100 


200 


300 


400 


500 


600 


700 


2640 


5280 


3 

4 
6 
7 
9 
11 
12 
14 


i in. Scr.f 
ti 

2 in. -fin. 

u 


3 in.-2 in. 
it 

u 


15 ft. drop 
(t 

15 ft. drop 

u 

Shoveled 

15 ft. drop 

a 

Shoveled 


7.3 
5.0 
2.6 
5.3 
3.5 
0.57 
3.5 
5.0 


8.3 

9.7 
3.7 
6.2 
4.1 
2.6 
4.2 
5.7 


8.9 
10.2 
4.9 
7.1 
4.8 
2.8 
4.5 
6.53 


9.2 
10.2 
5.3 
7.7 
5.3 
4.1 
4.8 
6.53 


9.5 
10.4 
5.3 
7.9 
5.3 
4.25 
5.0 
6.7 


10.1 
10.4 
5.3 
8.0 
5.7 
4.25 
5.0 
6.7 


10.1 
10.7 
5.4 
8.3 
6.5 
4.25 
5.1 
6.7 


11.2 
12.4 
5.4 
9.2 
7.3 
4.9 
6.0 
7.1 


11.2 
5.4 

4.9 
6.0 
7.1 



*These numbers refer to the series in Table 8. 
tDusty. 



14 



ILLINOIS ENGINEERING EXPERIMENT STATION 



The per cent of settlement of stone from three different lo- 
calities for a haul of practically one mile is given in Table 8; but 
the variation for any one size under identically the same condi- 
tions (for example, compare the first three lines of the table) is so 
great as not to warrant any attempt to draw conclusions. It was 
not possible to secure more accurate data except by an expendi- 
ture of time and money much greater than the value of the infor- 
mation seemed to justify. 

{Settlement in Cars: The shortage of cars at the time 
these experiments were made and the desire of the shipper 
and also of the railway to hurry shipments forward 
seriously interfered with the scope and value of these 

TABLE 8 
SETTLEMENT OF CRUSHED STONE IN TRANSIT IN WAGONS 



ll 


ho 
1 1 

O 


m 


Pi 


Per Cent of 
Settlement 

I 


0} O 
S ** 


wj 

cc 

s 


OQ 

1 





Chester Limestone by Mr. Schafmayer 




1 


15 ft. drop 


1.41 


1.23 


12.7 


f-in. Scr. 


1 


Same for i mile 
















Mostly dust 


2 


15 ft. drop 


1.41 


1.25 


11.4 


f-in. Scr. 


1 


Same for i mile 


3 


" 


1.41 


1.25 


11.4 


" 


1 


u u u 


4 


11 


1.41 


1.23 


12.7 


' 


1 


Stone dusty, wet 








Mean 


11.8 








5 


15 ft. drop 


1.41 


1.25 


11.4 


2-in.-| in. 


1 


Same for 2 miles 


6 


I 4 


1.41 


1.33 


5.7 




1 


Same for } mile 


7 


M 


1.41 


1.28 


9.2 


" 


1 




8 


Shoveled 


1.41 


1.23 


12.7 


it 


1 


Same for | mile 


9 


11 


1.41 


1.31 


7.1 


" 


1 


Stone damp 








Mean 


9.2 








10 


15 ft. drop 


1.41 


1.27 


10.1 


3-in.-2 in. 


1 


A few tailings 


11 


" 


1.41 


1.34 


4.9 


4 I 


1 


Same for -J mile 


12 


" 


1.41 


1.32 


6.4 


*' 


1 


" " " 


13 


Shoveled 


1.41 


1.23 


12.7 





1. 


A few tailings 


14 


< t 


1.41 


1.31 


7.1 


U 


1 


Same for | mile 
















Stone dirty 










Mean 


8.2 









BAKER WEIGHT OF CRUSHED STONE 
TABLE 8 (Continued) 



15 



it 


Method 
of Loading 


&$t 

o>i 


1** 

&>i 


Per Cent of 
Settlement 


og 

3 
m 


8 

ll 

^a 
.2 

Q 


1 

c3 

5 

09 

tf 




Kankakee Limestone by Mr. Bowling 




15 
16 


* 
* 


1.80 
1.61 


1.61 
1.46 
Mean 


10.6 
9.3 


f-in. Scr. 

n 


1 
1 


Chute at incline 
of 30 

U (( 


10.0 


17 

18 


X- 
X- 


1.80 
1.61 


1.67 
1.45 

Mean 


7.2 
9.9 


li in.-f-in. 

u 


1 

If 


U (( U 

u u u 


8.6 




Joliet Limestone by Mr. Bowling 




19 
20 


4 ft. drop 

< i 


1.81 
1.86 


1.66 
1.69 


8.3 
9.1 


Hn. Scr. 
.< 


1 
i 


Chute at incline 
of 45 

(( (( U 


21 


ii 


1.81 


1.63 
Mean 


9.9 


n 


i 


ii U U 


9.1 


22 


4 ft. drop 


1.81 


1.69 


6.6 


2 in.-Hn. 


1 


u u 


23 


it 


1.79 


1.67 


6.7 


2 in.-Hn. 


i 


u u u 








Mean 


6.6 









* Lower end of chute even with top of wagon bed. 

experiments. (See Table 9). It will be noticed that the 
settlement varies greatly for stone of the same size, loaded 
the same day, and shipped to the same destination on the 
same train, for example, compare the second, third and fourth 
lines of the table. The settlement was measured by the same 
method as previously described for wagons, and was as carefully 
determined as possible by that method. Part of the error is doubt- 
less due to a variation in the freedom with which the crushed stone 
ran out of the loading chute, and to a variation in the details of 
the method employed in leveling off the load. 



16 



ILLINOIS ENGINEERING EXPERIMENT STATION 



TABLE 9 

SETTLEMENT OF CRUSHED STONE IN TRANSIT 
IN KAIL WAY CARS 



CC O 


U 

^H 


pJi 


if 


1 cb 

Q> r-S C 

O -M rj 

| % S 


J'go 
GO -^ 

rjl 


Destination 


CD 

^ 




Joliet Limestone by Mr. Schafmayer 




1 


8 ft. drop 


2.4 


2.4 


0.0 


|-in. Scr. 


Springfield 


149 


2 


8 ft. drop 


2.4 


2.2 


8.3 


u u 


McLean 


105 


3 


it 


2.0 


1.75 


12.5 


U (. 


u 


u 


4 


u u 


2.6 


2.3 


8.3 


U (i 


" 


" 








Mean 


9.7 








5 


8 ft. drop 


2.1 


2.08 


1.4 


2 in.-i-in. 


Springfield 


149 


6 


u u 


2.2 


1.9 


13.9 


u u 


" 










Mean 


7.6 








7 


8 ft. drop 


2.3 


2.1 


8.7 


U (( 


McLean 


105 


8 





2.2 


1.9 


13.9 


u u 


" 


u 


9 


t u 


2.7 


2.5 


7.4 


(i U 


(i 


u 


10 


It U 


2.6 


2.33 


9.7 


u a 


u 


u 


11 


U <( 


2.6 


2.4 


7.7 





" 


(I 








Mean 


9.5 








12 


8 ft. drop 


2.6 


2.5 


3.8 


3 in.-2 in. 


Springfield 


149 


13 


U 11 


2.6 


2.3 


10.5 


u u 


u 










Mean 


7.2 








14 


8 ft. drop 


2.2 


1.95 


11.4 




McLean 


105 


15 




3.2 


3.1 


3.4 




" 


u 


16 




2.1 


2.0 


5.0 




' 


<( 


17 




2.7 


2.35 


12.9 




11 


u 


18 




2.7 


2.6 


3.7 




it 


u 


19 




2.2 


2.2 


0.0 




u 


u 


20 




3.33 


3.0 


9.0 




C( 


u 


21 




2.3 


2^05 


10.8 




1 


u 


22 




2.7 


2.5 


7.4 




4 


11 


23 




2.7 


2.45 


9.2 




1 


u 


24 




2.7 


2.4 


11.1 




I 


" 


25 




2.6 


2.35 


9.6 




' 


u 


26 


" 


2.2 


2.0 


9.1 




u 


11 








Mean 


10.2 









BAKER WEIGHT OF CRUSHED STONE 
TABLE 9 (Continued) 



17 



6 
5 

4-3 

GQ 




T3 b> 

o a 
lol 

a 3 


ls"L 

bogVlg 

ga^T 


S^l" 

c3 cu X <D 

&S* 


<Un 
|ll 


J-o 1 

M 


Destination 


* * 
fs 

go_. 

J 3 

B 




Joliet Limestone by Mr. Bowling 




1 


8 ft. drop 


2.37 


2.17 


8.4 


Hn. Scr. 


Bloom'ton 


91 


2 
3 


u u 
u u 


2.52 

2.80 


2.31 
2.62 

Mean 


8.3 
6.4 


2 in.-|-in. 

U it 


( ( 
<( 


(1 

U 


7.4 


4 


u u 


2.57 


2.37 


7.8 


3 in.-2 in. 


u 


U 




Chester Limestone by Mr. Schafmayer 




1 

2 
3 


15 ft. drop 

U (( 

< t u 


3.00 
2.75 
2.50 


2.7 
2.4 
2.25 

Mean 


9.5 
12.5 

9.8 


i-in. Scr. 

U 11 

u u 


Springfield 

u 
u 


180 

u 
({ 


10.6 


4 
5 
6 


Barrows 
15 ft. drop 
Barrows 


2.67 
3.00 

2.58 


2.58 
2.7 
2.33 

Mean 


3.4 
9.5 

8.2 


3 in.-2 in. 

u u 
u u 


u 
i ( 
u 


i( 
(( 

u 


7.0 




Kankakee Limestone by Mr. Bowling 




1 


8 ft. drop 


2.27 


2.15 


5.4 


2J in.-f in. 


Bloom'ton 


86 



It is probable that part of the difference is due to the 
difference in the care employed in switching the car from the load- 
ing chute. At Joliet the cars were switched about a mile from the 
crusher to the yards in the city, to be weighed; and at the time they 
were weighed a casual examination was made of the settlement, 
and the conclusion was drawn that from i to i of the total settle- 
ment took place while the cars were being switched. The cars 
were continually being moved while they were in the yard, and 



18 



ILLINOIS ENGINEERING EXPERIMENT STATION 



hence more accurate observations could not be made as to the 
effect of switching upon the settlement. The distance from 
Joliet to McLean is 105 miles, and apparently a further haul of 
44 miles to Springfield did not materially increase the settlement. 
The great variations in results obtained under seemingly like 
conditions make it unwise to attempt to draw any conclusions. 
Apparently more tests must be made before any reliable conclu- 
sion can be stated concerning the total amount of the settlement 
or the law of its variation. 

The depth of load in Table 9 is the mean of nine separate 
measurements, and was computed to the nearest hundredth of a 
foot although it is recorded only to the nearest tenth. The more 
accurate values were employed in computing the per cent of settle- 
ment. However, to eliminate any possibility of error in the arith- 
metical work, the per cent of settlement was computed to a great- 
er number of places than is justified by the data. A similar state- 
ment applies to several of the tables in the subsequent parts of this 
paper. 

Summary of Data on Settlement: A summary of the data in 
Tables 8 and 9 is given in Table 10. 

TABLE 10 
SUMMARY OF DATA ON SETTLEMENT 



Ref. 
No. 


Location 
of 
Quarry 


Size 
of 
Stone 


Settlement after a 
Haul of 


| mile or 
more in 
wagons 


75 miles or 
more in 
cars 


1 
2 
3 
4 

5 
6 

7 
8 
9 

10 
11 
12 


Chester 

1 1 

1 1 
(i 

Joliet 


< * 

f < 

Kankakee 

u 

it 


f-in. Scr. 
f . 

2 irk-f in. Scr. 
3 in. -2 in. " 

i in. Scr. 

8 i< 

2 in.-i in. Scr. 
2in.-i " " 
3 in.-2 in. 

f in. Scr. 
li in.-f in. Scr. 
2Jin.-f " " 


12.7 
11.8 
9.2 
8.2 

9.1 




10.6 


7.0 

8.4 
9.7 
7.4 
9.5 

7.8 


6.6 




10.0 

8.6 




5.4 





BAKER WEIGHT OF CRUSHED STONE 19 

V. WEIGHT PER CUBIC YARD OF CRUSHED LIMESTONE 

Broken stone is usually sold by weight even though the unit 
is nominally the cubic yard, since it is the custom to determine 
the number of cubic yards in a shipment by weighing the ship- 
ment and dividing the total weight by the supposed weight of a 
cubic yard. It does not appear that any adequate observations 
have been made to determine the weight of a unit of volume of 
the different sizes and kinds of crushed stone. 

Tests to determine the weight of a unit of volume of crushed 
limestone were made on stone from Joliet, Kankakee, and Chester, 
both in wagons and in cars, at the same time the record was taken 
of the settlement, as previously described. 

Before beginning to load a car, measurements were taken 
from a straight edge laid on top of the car body to the floor of 
the car. These measurements were taken on each side of the car 
and at the center transversely, and at each end and the middle 
longitudinally. The stone was loaded into the cars by means of 
a chute in the bottom of the bin. After the car was loaded the 
upper surface was leveled off, and the depth of the stone below 
the top of the car body was determined by measuring down from 
a straight edge across the top of the car to a similar straight 
edge lying on the crushed stone. Prom the above measurement 
the volume of the stone was computed. 

The cars were then switched to the scale track where they 
were weighed by a representative of the National Weighing Asso- 
ciation, each weight being verified by either Mr. Schafmayer or 
Mr. Bowling. Prom these data the weight per cubic yard of the 
loose stone was computed. Measurements similar to those made 
at the crusher were taken when the car reached its destination; 
and the weights per unit of volume of the stone when compacted 
were computed as before. 

The data and results of the observations on Joliet, Chester, 
and Kankakee stone are given in Tables 11, 12 and 13 respectively. 
For car loads, the "original weight" is after the car was 
switched about a mile, and the "final weight" is after being 
shipped 75 miles (a greater distance makes practically no differ- 
ence); and for wagon loads the weights are at the loading bin and 
after being hauled a half mile or more. 



20 ILLINOIS ENGINEERING EXPERIMENT STATION 

TABLE 11 
WEIGHT PER CUBIC YARD OF JOLIET LIMESTONE 



4-3 
GO 

& 


M 

o o 

<> 

N 

tt 


S2 

s 

3 

cn 


53 f-| rrt 

a^ 

.^6d 

6*2 


& 

1! 

fe o 


U* 

V 


Eat 

c3 . . 

C> 3 

S~ 




Car Loads by Mr. Schafmayer 






1 


|-in. Scr. 


94500 


36.0 


36.0 


2625 


2625 


2 





75500 


28.9 




2612 




3 


u 


94400 


34.6 


31.7 


2730 


2980 


4: 


ft 


54700 


20.9 


18.2 


2610 


3000 


5 


u 


96900 


36.2 


33.2 


2680 


2920 










Mean 


2652 


2881 


6 


2 in.-|-in. 


78700 


30.6 


30.2 


2570 


2600 


7 





69700 


31.5 


27.1 


2210 


2570 


8 


u 


58500 


24.8 


22.7 


2360 


2580 


9 





54300 


23.6 


20.3 


2300 


2680 


10 


(( 


67500 


31.0 


29.1 


2180 


2320 


11 


u 


82600 


37.5 


34.0 


2200 


2430 


12 


(( 


84400 


37.5 


34.8 


2250 


2430 










Mean 


2296 


2516 


13 


3 in.-2 in. 


92400 


36.6 


35.2 


2520 


2620 


14 





52700 


23.0 




2290 




15 


(i 


102300 


42.0 


40.6 


2440 


2620 


16 





78600 


31.8 




2470 




17 





63050 


25.2 


23.6 


2500 


2670 


18 





66600 


27.7 


24.3 


2380 


2740 


19 


{( 


88600 


38.6 


37.4 


2300 


2370 


20 


u 


75800 


31.6 


- 31.6 


2400 


2400 


21 


u 


94800 


41.4 


37.7 


2290 


2520 


22 


u 


69000 


30.0 


26.4 


2300 


2610 


23 


(( 


87900 


38.8 


36.0 


2270 


2440 


24 


u 


88300 


38.8 


35.4 


2275 


2490 


25 


(( 


86900 


38.8 


34.8 


2240 


2500 


26 


(( 


72800 


32.2 


28.8 


2260 


2530 


27 


u 


88200 


36.5 




2420 




28 


It 


91000 


37.2 




2426 




29 


u 


91300 


37.5 


33.9 


2430 


2690 


30 


(( 


76800 


31.3 


28.5 


2450 


2700 










Mean 


2370 


2564 



BAKER WEIGHT OF CRUSHED STONE 

TABLE 11 (Continued) 
WEIGHT PER CUBIC YARD OF JOLIET LIMESTONE 



21 



-J-3 
02 O 

H* 




<D O 

2-2 
S 00 


<*- 

o 
. v 

+3 C 

fe- 

P-3 

OJ 


1'S'P 
Sod 

Ml>- 3 

o^ 


feN 

5^ > 

73 s 

C W 

5*8 


1^ 

Ss^ 

Q^ o 
^ 


4^ 

^ S'd 

a>, 

ls 

5 




Car Loads by Mr. Bowling 






31 


f-in. Scr. 


83800 


31.52 


28.85 


2659 


2905 


32 

33 


2 in.-f-in. 



82800 
79600 


34.40 
33.64 


31.82 
30.82 

Mean 


2407 
2366 


2602 
2583 


2386 


2592 


34 


3 in. -2 in. 


58300 


26.47 


24.37 


2202 


2392 




Wagons Loaded by Mr. 


Bowling 








35 
36 
37 


i-in. Scr. 

u 
(( 


4195 
4260 
4165 


1.81 
1.86 

1.81 


1.66 
1.69 
1.63 

Mean 


2318 
2290 
2301 


2527 
2521 
2555 


2303 


2533 


38 
39 


2 in. -i-in. 

u 


4185 
4150 


1.81 
1.79 


1.69 
1.67 

Mean 


2312 
2318 


2476 
2485 


2315 


2480 



It will be noticed that there is considerable variation in both 
the original and the final weight per cubic yard. Notwithstand- 
ing the variation it is believed that the number of observations is 
so great as to make the means reasonably reliable; but the table 
shows that the maximum error of any one observation may be as 
much as 10 per cent, and hence great accuracy can not be expected 
from a single observation. Similar results are shown for Chester 
stone, see Table 12. There are three errors that affect these 
results: (1). Errors in determining the value of the stone at the 
quarry and at the destination. (2). Errors in the weight of the 
car as stenciled upon it. The original weight may have been de- 



22 



ILLINOIS ENGINEERING EXPERIMENT STATION 



TABLE 12 
WEIGHT PER CUBIC YARD OF CHESTER LIMESTONE 



u 


o> 

M 

& 


=s. 

I 


eSt-i 

c oT 5 

So? 
EZ 3 

o 


rtl 

s*g 


g&d 

B o ^ 
#~d 

S 


iS* 

- t i 


.Remarks 




Car Load by Mr. Schafmayer 




1 


i-in. Scr. 


109100 


41.97 


38.0 


2600 


2870 


Damp 


2 


u 


70600 


28.14 


24.6 


2509 


2870 




3 


(( 


92900 


36.72 


.33.1 


2530 


2810 












Mean 


2546 


2850 




4 


3 in.-2 in. 


96500 


41.60 


38.2 


2320 


2530 


Hand made 


5 





81500 


32.91 


31.8 


2476 


2560 


Damp 










Mean 


2398 


2545 




6 


3 in.-2 in. 


106100 


41.97 


38.0 


2528 


2790 


Wet 




Wagon Loads by Mr. Schafmayer 




7 


i-in. Scr. 


3550 


1.41 


1.23 


2518 


2886 


15 ft. drop 


8 




3550 


1.41 


1.25 


2518 


2840 


15 ft. drop 


9 




3460 


1.41 


1.25 


2450 


2770 


15 ft. drop 


10 




3420 


1.41 


1.23 2425 


2780 


15 ft. drop 


11 




2430 


1.00 




2430 




No haul, 15 ft. drop 


12 




2395 


1.00 




2395 




No haul, 15 ft. drop 


13 




2435 


1.00 




2435 




No haul, 15 ft. drop 










Mean 


2453 


2819 




14 


2 in.-f-in. 


3360 


1.41 


1.28 


2380 


2625 


15 ft. drop 


15 


a 


3250 


1.41 


1.23 


2305 


2642 


Shoveled 


16 


u 


3460 


1.41 


1.33 


2450 


2600 


15 ft. drop 


17 


( i 


3200 


1.41 


1.31 


2270 


2445 


Shoveled 


18 


u 


2375 


1.00 




2375 




No haul, 15 ft. drop 


19 


(( 


2320 


1.00 




2320 




No haul, 15 ft. drop 


20 





3250 


1.41 


1.25 


2305 


2600 


No haul, 15 ft. drop 










Mean 


2444 


2582 




21 


3 in -2 in. 


3200 


1.41 


1.23 


2270 


2601 


Shoveled ~ 


22 




3330 


1.41 


1.33 


2360 


2505 


15 ft. drop 


23 




2390 


1.00 




2390 




No haul, 15 ft. drop 


24 




3480 


1.41 


1.34 


2470 


2595 


15 ft. drop *~~^ 


25 




3290 


i.41 


1.31 


2335 


2510 


Part dirt, shoveled 


26 




2370 


1.00 




2370 




No haul, 15 ft. drop 


27 




3350 


1.41 


1.27 


2376 


2638 


15 ft. drop 










Mean 


2367 


2570 





BAKER WEIGHT OF CRUSHED STONE 



23 



termined when the car was wet; while in the observations under 
consideration the cars were dry. (3). In weighing a string of 
cars, either empty or loaded, there is some error due to the action 
of the coupler. 

Table 11 shows that the weight per cubic yard of screenings 
is more than that of coarser stone, but also shows that 3-in. stone 
weighs more per cubic yard than 2-in. Similar results obtained 
for wagon loads, and also for Chester and Kankakee stone, both 
for car loads and for wagon loads see Tables 12 and 13. 

TABLE 13 
WEIGHT PER CUBIC YARD OF KANKAKEE LIMESTONE 



6 


I 


^ 





*o 


gi 


*t 


2 


ft 


DQ 


4-3 '""' 


^> 


o r ^ 


3 


^ d -s 




H 






15 


^ 


1 2 


<a 

03 S_ 


1 


H 


<D 


1? 


5^"^ r^ 






I-H Q) 

jSOft 


S ^ 


3 




f 






5 


o 











Car Load by Mr. Bowling 




1 


2iin,f-m. 


62900 


27.83 


26.32 


2260 


2390 








Wagon Loads by Mr. Bowling 




2 


f-in. SCT. 


4085 


1.80 


1.61 


2270 


2537 




3 


" 


4170 


1.61 


1.46 


2590 


2856 












Mean 


2430 


2697 




4 


H in.-t in. 


3840 


1.80 


1.67 


2133 


2299 




5 


u 


4050 


1.61 


1.45 


2516 


2793 












Mean 


2325 


2546 





Summary of Weights: Taking an average of the preceding 
results for each size of stone from each quarry the summary 
shown in Table 14 is obtained. 



24 ILLINOIS ENGINEERING EXPERIMENT STATION 

TABLE 14 

SUMMARY OF WEIGHTS OF CRUSHED LIMESTONE 
Results in Pounds per Cubic Yard 









Wagon Loads 


Car Loads 


Ref. 

No. 


Location 
of 
Quarry 


Size 
of 
Stone 






+=S 
*$ 


**2i 


! 

C/5 


-1 S 2 








4D j 

| 


5|1 


^1 


^|| S 


1 


Joliet 


|-in. Scr. 


2303 


2533 


2659 


2905 


2 


" 


f-in. Scr. 






2652 


2882 


3 


" 


2 in.-i-in. 


2315 


2480 


2386 


2592 


4 


" 


2 in.-|-in. 






2296 


2516 


5 


" 


3 in.-2 in. 






2361 


2553 


6 


Chester 


f-in. Scr. 


2442 


2797 


2546 


2850 


7 


" 


2 in.-f-in. 


2344 


2582 






8 


" 


3 in.-2 in. 


2367 


2569 


2348 


2545 


9 


Kankakee 


f-in. Scr. 


2430 


2697 






10 


" 


li in.-f-in. 


2325 


2546 






11 


" 


2i in.-f-in. 






2260 


2390 



Relations between Actual a?td Nominal Weight of Crushed Stone. 
As is well known, it is the universal custom to load a car more 
than its rated capacity; and similarly it seems to be the custom of 
laborers when loading a car with crushed stone, to put in more 
than directed. This fact causes an erroneous idea of the weight 
of a yard of the material among the railway officers, as they weigh 
the car and divide the weight of the stone by the nominal number 
of yards to obtain the weight per cubic yard. Since the actual 
volume is not measured, the number of yards is taken from the 
bill of lading submitted by the shipper, which is approximate and 
is usually too small; and consequently the weight per cubic yard 
derived by this method is usually somewhat too great. For ex- 
ample, the Superintendent of the Wabash, Chester and Western 
Railway weighed a large number of cars of stone at Chester, and 
obtained by this method weights of 2600 pounds and over per 
cubic yard. In all his observations the number of yards was 
taken as given on the bills. 



BAKER WEIGHT OF CRUSHED STONE 



25 



To determine the relation between the actual weight of 
crushed stone and the weight found as above, accurate measure- 
ments of ten cars being loaded at Chester were made by Mr. 
Schafmayer to ascertain if the high weights per cubic yard ob- 
tained by the railroad were due to overloading. The results of 
these tests are shown in Table 15. In every case the actual con- 
tents of the car are greater than the number of yards in the bill. 
The average excess is 1.71 yards for an average nominal load of 
26 yards, an average excess of 6.6 per cent. This gives an appar- 
ent average weight of 2558 pounds for a yard actually weighing 
only 2400 pounds. It can be readily seen that under such con- 
ditions, it is not surprising that railway officials have an exag- 
gerated idea as to the weight of a cubic yard of crushed stone. 

TABLE 15 
EXCESS OF ACTUAL LOADING IN CARS. OVER BILLING 





CO g 




o5 w 


43 


J -d 


43 T3 


. 


^S'o & 


*j 5 


S lj I? 




* * 


C.Q ^ 


tfft 


g gS'g 


1" 


*0^^g 


^ M 


1^ 


c r3 




^^CQj 


"^fc O 


6 C3 ^ 


& ^ 


o g 


S"^ ^ 




!^^ 




^5*^ 




<1 ft 


ft 


1 


25 


25.7 


0.7 


2.8 


2420 


2488 


2 


25 


25.7 


0.7 


2.8 


2420 


2488 


3 


25 


27.7 


2.7 


10.8 


2420 


2684 


4 


25 


27.7 


2.7 


10.8 


2420 


2684 


5 


25 


27.7 


2.7 


10.8 


2420 


2684 


6 


25 


25.8 


0.8 


3.2 


2420 


2510 


7 


30 


32.0 


2.0 


6.7 


2420 


2583 


8 


25 


25.7 


0.7 


2.8 


2420 


2488 


9 


30 


31.4 


1.4 


4.7 


2420 


2534 


10 


25 


27.7 


2.7 


10.8 


2420 


2684 


AY. 


26 


27.71 


1.71 


6.6 


2420 


2581 



VI. COEFFICIENTS 



FOR DETERMINING WEIGHT OF CRUSHED 
STONE 



In the introduction it was suggested that possibly coefficients 
could be determined by which to deduce the weight per unit of 
volume of crushed stone when the weight of a unit of solid stone 
or the specific gravity was known. Table 16 shows such coeffi- 
cients for the various sizes for three kinds of stone, at the crusher 
and also at the destination, both in cars and in wagons. The 



26 



ILLINOIS ENGINEERING EXPERIMENT STATION 



TABLE 16 

COEFFICIENTS BY WHICH TO DETERMINE THE WEIGHT IN POUNDS 
PER CUBIC YARD OF CRUSHED LIMESTONE 



Kind 
of 
Stone 


Size 
of 
Stone 


Having- the 
Weight of a 
Cu. Ft. of 
Solid Stone 


Having the 
Weight of a 
Cu. Yd. of 
Solid Stone 


Having the 
Specific Gravity 


3 

i^ 

*H oTp 
o a o 

^1 


Coeffi- 
cient 


f* 

S3 

$ 


Coefficient 


. <D 

*H C 

Oo 

d^ 

GO'S 


Coefficient 


N 

c3 



1 


FH 



I 




1 


c 
o 
bt 
c9 


Chester 

Joliet 


Kankakee 

Mean 
Kankakee 

Chester 

Joliet 


Kankakee 
Mean 

Chester 
Joliet 

Mean 

Chester 

Joiiet 
(i 

Kankakee 

Mean 
Kankakee 

Chester 

Joliet 
tt 

Kankakee 
Mean 

Chester 
Joliet 

Mean 


|-in. Scr. 
i-in. Scr. 
f-in. Scr. 
Hn. Scr. 


We 

160.4 
169.1 
169.1 
162.8 


,ight 
15.9 
15.7 
15.4 


at < 
15.3 
13.6 

14.9 


3rusl 
4331 
4566 
4566 
4397 


ier 

0.588 
0.582 
0.572 


0.566 
0.504 

0.553 


2.57 
2.71 

2.71 
2.61 


990.7 
981.2 
963.8 


954.5 

849.8 

931.0 


Hn. Scr. 
lirin.-fin. 

2 in.-|-in. 
2 in.-Hn. 
2 in.-f-in. 
2iin.-t-in. 


165.4 
162.8 

160.4 
169.1 
169.1 
162.8 


15.7 

14.1 
13.6 
13.9 

13.9 

14.9 
14.0 


14.6 
14.3 

14.6 
13.7 

14.2 
14.8 


4465 
4397 

4331 
4566 
4566 
4397 


0.581 

0.523 
0.503 
0.514 


0.541 
0.529 

0.541 
0.507 


2.65 
2.61 

2.57 
2.71 
2.71 
2.61 


978.6 

880.4 
847.2 
865.9 


911.8 
890.8 

912.1 
854.2 


2 in. 4 in. 

3 in.-2 in. 
3 in x -2 in. 


165.4 

160.4 
169.1 


4465 

4331 
4566 


0.513 

0.554 
0.517 


0.524 
0.546 


2.65 

2.57 
2.71 


864.5 

933.1 

871.2 


883.2 
921.0 


3 in.-2 in. 

f-in. Scr. 
|-in. Scr. 
|-in. Scr. 
|-in. Scr. 


164.8 
Weig 
160.4 
169.1 
169.1 
162.8 


14.4 
ht a 

17.8 
17.2 
16.9 


14.8 
t De 
17.6 
15.0 

16.6 


4448 
.stint 
4331 
14566 
'4566 
4397 


0.536 
ition 
0.658 
0.636 
0.625 


0.546 

0.651 
0.555 

0.613 


2.64 

2.57 
2.71 
2.11 
2.61 


902.2 

1108.9 
1072.0 
1053.5 


921.0 

1096.9 
934.7 

1033.3 


i-in. Scr. 
liin.-f-in. 

2 in.-f-in. 
2 in.-Hn. 
2 in.-S-in. 
2Jin.-|-in. 


165.4 
162.8 

160.4 
169.1 
169.1 
162.8 


17.3 

15.3 
14.9 
14.7 


16.6 
15.6 

16.1 
14.7 


4465 
4397 

4331 
4566 
4566 
4397 


0.640 

0.568 
0.551 
0.544 


0.606 
0.579 

0.596 
0.543 


2.65 
2.61 

2.57 
2.71 
2.71 
2.61 


1078.1 

956.5 
928.4 
915.7 


1021.6 
975.5 

1004.7 
915.1 


2 in.-Hn. 

3 in.-2 in. 
3 in.-2 in. 


165.4 

160.4 
169.1 


15.0 

15.9 
15.1 


15.4 
16.0 


4465 

4331 
4566 


0.554 

0.588 
0.559 


0.570 
0.593 


2.65 

2.57 
2.71 


933.5 

990.2 
942.0 


959.9 
1000.0 


3 in.-2 in. 


164.8 


15.5 


16.0 


4448 


0.574 


0.593 


2.64 


966.1 


1000.0 



BAKER WEIGHT OF CRUSHED STONE 27 

means are stated in Table 16 in such a manner as to show the 
average result *f or each size. 

Disregarding whether the stone is measured in a car or a 
wagon, and also disregarding whether it is measured at the crush- 
er or at its destination, the following summary of Table 16 is ob- 
tained. 

MEAN COEFFICIENT BY WHICH TO MULTIPLY 

nip o^ THE WEIGHT OF A CUBIC FOOT OF SOLID 

LIMESTONE TO OBTAIN THE WEIGHT OF A 
CUBIC YARD OF THE CRUSHED STONE 

i-in. screening's 15.5 

2 in. to i inch 14.6 

3 in. to 2 inch.. 15.2 



Average 15.1 

Notice that the coefficient is largest for the finest stone, and 
smallest for the intermediate size. The same is true for trap 
(see Table 17) even though the sizes slightly differ. This seems 
to prove that the weight of screenings is greater than that of 
coarser stone, while the weight of the intermediate size is less 
than that of either extreme size. 



28 ILLINOIS ENGINEERING EXPERIMENT STATION 

APPENDIX I 
WEIGHT OF VOIDS OF CRUSHED TRAP 

A careful search has been made of engineering literature, and 
below is the only definite information discovered. 

In the Journal of the Association of Engineering Societies, 
Volume 11 (1892), page 424, W. E. McClintock, at present Chair- 
man of the Massachusetts Highway Commission, gives an account 
of six experiments made by him to determine the weight of a unit 
of volume of crushed trap. In the first experiment he weighed 
the contents of a bin holding 29i cubic yards,* and found the 
weight of stone that had passed a i-inch screen to be 2605 pounds 
per cubic yard, and in another test under the same conditions, 
to be 2690 pounds; and when the broken stone was wet the weight 
was 2480 pounds per cubic yard. In another experiment he 
weighed the stone in a bin holding 89.8 cubic yards, and found 
the weight of stone that had passed a 1^-inch screen and had 
been caught on a i-inch screen to be 2423 pounds per cubic yard. 
In a third experiment he weighed the stone in a bin containing 
89.7 cubic yards, and found the weight of the stone that had 
passed a 3-inch screen and had been caught on a It-inch screen to 
be 2522 pounds per cubic yard. He also measured six cars and 
weighed the contents, and found the weight of the last mentioned 
size to be 2531 pounds per cubic yard. The following statement 
shows the relative proportions of the several sizes of crushed 
trap. 
SIZE OF STONE PER CENT 

i-inch screenings 13.24 

H inch to i-inch , 23.89 

3 inch to 1| inch 62.87 

Total output of crusher 100.00 

Prom the weight per cubic foot of solid stone given by Mr. 
McClintock and the above weights of the broken stone, the per 
cent of voids was computed. A summary of Mr. McClintock's 
experiments is given in Table 17, and the coefficients for trap 
are given in Table 18. 



*Mr. McClintock privately informed the writer that the average drop of the stone into 
the bins was about 8 feet. 



BAKER WEIGHT OF CRUSHED STONE 

TABLE 17 
WEIGHT AND VOIDS OF CRUSHED TRAP 



29 



Kef. 
No. 


Size of Stone 


Weight 
in Ib. per 
cu. yd. 


Per Cent 
of Voids, 
computed 


1 
2 


i- in. Screenings, in bin, dry 

u u 

Mean 


2605 
2690 


46.5 


2648 


3 


in bin, wet 


2480 




4 


1| in. to | in. in bin 


2432 


50.2 


5 
6 


3 in. to li in. in bin 
in cars 

Mean 


2522 
2531 


48.1 


2526 



TABLE 18 

COEFFICIENTS BY WHICH TO DETERMINE THE WEIGHT IN 
POUNDS PER CUBIC YARD OF CRUSHED TRAP 



Kef. 
No 


Size of Stone 


Having the 
Weight of a 
Cubic Foot of 
Solid Stone 


Having the 
Weight of a 
Cubic Yard of 
Solid Stone 


Having the 
Specific 
Gravity 






Wt. of 




Wt. of 












Sol. Stone 


Coeffi- 


Sol. Stone 


Coeffi- 


Specific 


Co- 






Ib. per 
cu. yd. 


cient 


Ib. per 
cu. yd. 


cient 


Gravity 


effi- 
cient 


1 


i-in. screenings 


180.7 


14.6 


4879 


0.541 


2.90 


914.4 


2 


1} in.-i in. 


180.7 


13.5 


4879 


0.500 


2.90 


839.7 


3 


3 in.-U in. 


180.7 


13.9 


4879 


0.515 


2.90 


872.2 




Mean 




13.7 




0.519 




875.4 



















THE 



UNIVERSITY 1 

OF 



PUBLICATIONS or THE ENGINEERING EXPERIMENT STATION 



Bulletin No. 1. Tests of Reinforced Concrete Beams, by Arthur N. Talbot. 1904. (Out 
of print.) 

Circular No. 1. High Speed Tool Steels, by L. P. Breckenridge. 1905. 

Bulletin No. 2. Tests of High-Speed Tool Steels on Cast Iron, by L. P. Breckenridge 
and Henry B . Dirks. 1905. 

Circular No. 2. Drainage of Earth Roads, by Ira O. Baker. 1906. 

Bulletin No. 3. The Engineering Experiment Station of the University of Illinois, by 
L. P. Breckenridge. 1906. (Out of print.) 

Bulletin No. 4. Tests of Reinforced Concrete Beams. Series of 1905, by Arthur N. 
Talbot. 1906. 

Bulletin No. 5. Resistance of Tubes to Collapse, by Albert P. Carman. 1906. (Out of 
print.) 

Bulletin No. 



Holding Power of Railroad Spikes, by Roy I. Webber. 1906. 

Fuel Tests with Illinois Coals, by L. P. Breckenridge, S. W. Parr and 

Tests of Concrete: I. Shear; II. Bond, by Arthur N. Talbot 1906. (Out 



6. 

Bulletin No. 7. 
Henry B. Dirks. 1906. 

Bulletin No. 8. 
of print.) 

Bulletin No. 9. An Extension of the Dewey Decimal System of Classification Applied 
to the Engineering Industries, by L. P. Breckenridge and G. A. Goodenough. 1906. 

Bulletin No. 10. Tests of Concrete and Reinforced Concrete Columns, Series of 1906, by 
Arthur N. Talbot, 1907. 

Bulletin No. 11. The Effect of Scale on the Transmission of Heat through Locomotive 
Boiler Tubes, by Edward C. Schmidt and John M. Snodgrass. 1907. (Out of print.) 

Bulletin No. 12. Tests of Reinforced Concrete T-beams. Series of 1906, by Arthur N. 
Talbot. 1907. 

Bulletin No. 13. An Extension of the Dewey Decimal System of Classification Applied 
to Architecture and Building, by N. Clifford Ricker. 1907. 

Bulletin No. 14. Tests of Reinforced Concrete Beams. Series of 1906, by Arthur N. 
Talbot. 1907. 

Bulletin No. 15. 

Bulletin No. 16. 

Bulletin No. 17. 
Wheeler. 1908. 

Bulletin No. 18. 

Bulletin No. 19. 



How to Burn Illinois Coal without Smoke, by L. P. Breckenridge. 1908. 

A Study of Roof Trusses, by N. Clifford Ricker. 1908, 

The Weathering of Coal, by S. W. Parr. N. D. Hamilton, and W. F. 



The Strength of Chain Links, by G. A. Goodenough . 1908. 
Comparative Tests of Carbon, Metallized Carbon and Tantalum Fila- 
ment Lamps, by Thomas H. Amrine. 1908. 

Bulletin No. 20. Tests of Concrete and Reinforced Concrete Columns, Series of 1907, by 
Arthur N. Talbot. 1908. 

Bulletin No. 21. Tests of a Liquid Air Plant, by C. S. Hudson and C. M, Garland. 1908. 
Bulletin No. 22, Tests of Cast-Iron and Reinforced Concrete Culvert Pipe, by Arthur N. 
Talbot. 1908. 

Bulletin No. 23. Voids, Settlement and Weight of Crushed Stone, by Ira O. Baker. 1908. 



UNIVERSITY OF 



STATE UNIVERSITY 



INC.HJDESI TtJR 

COLLEGE OF LITERATURE AND ARTS (Ancient and 
Modern Languages and Literatures, Philosophical and Po- 
litical Science Groups of Studies, Economics, Commerce 
and Industry). 

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ADMINISTRATION. 

A Summer School with a session of nine weeks is open each 
summer. 

A Military Regiment is organized at the University for in- 
struction in Military Science. Closely connected with the 
work of the University are students' organizations for 
educational and social purposes. (Glee and Mandolin 
Clubs; Literary, Scientific, and Technical Societies and 
Clubs, Young Men's and Young Women's Christian As- 
sociations). 

United States Experiment Station, State Laboratory of Nat- 
ural History, Biological Experiment Station on Illinois 
JRiver, State Water Survey, .State Geological Survey. 

Engineering Experiment Station. A department organized 
to investigate problems of importance to the engineering 
and manufacturing interests of the State. 

The Library contains 95,000 volumes, and 17,000 pam- 
phlets. 

The University offers 526 Free Scholarships. 
For catalogs and information address 

W. L. PILLSBURY, Registrar. 

Urbana, Illinois. 



Illinois 
State 

Retormatwy 
Print. 



Univ. of I 



linois. 

ng experiment 



135 
v. 25 



station. 
'1 



Bulletin, 
37:6 



UNAV'/ of 

169957 



UN 



i/i^ Z 



LIBRARY