8 
BULLETIN 1077, TJ. S. DEPARTMENT OF AGRICULTURE. 
pounds per square inch. Pavements composed of concrete of less 
strength have generally proved unsatisfactory. 
In practice it is generally not feasible to follow strictly any of 
the theories in the proportioning of the materials. The aggregates 
must usually be obtained from commercial sources and the specified 
grading of these aggregates must be such that they can be supplied 
without excessive expense or decreased output. The maximum size 
usually specified ranges from L| to 2J inches. When the 2J-inch 
size is permitted it is usually provided that 90 to 95 per cent of the 
aggregate shall pass a 2-inch circular opening. For sand graded as 
described on page 4 and a coarse aggregate, well graded from i inch 
to lJ inches, the proper proportions for concrete pavements would 
be 1 part of cement to 2 parts of fine aggregate to 3 parts of coarse 
aggregate. For coarse aggregate from J inch to 2-J inches in size, 
a proportion of 1:2:3} or even 1:2:4 may be used provided there 
is sufficient mortar to finish the concrete properly. These propor- 
tions may have to be altered slightly, but for good commercial ag- 
gregate graded as described on page 5 the proportions given will 
prove satisfactory. Where it is not possible to obtain commercially 
graded aggregates of the sizes mentioned, different proportions of 
aggregate should be used. The following table, 5 which gives a 
large number of proportions designed to produce concrete of ap- 
proximately 3,000 pounds compressive strength at 28 days when 
mixed with the water necessary to give a workable consistency, 
indicates the great variety of combinations that can be used. 
Abrams's table of proportions and quantities for one cubic yard of concrete. 
[Based upon laboratory investigations, using approved materials, compressive strength, 28 davs, with 
workable plasticity, 6 by 12-inch cylinders, 3,000 pounds per square inch.] 
Cen 
lent in barrels, a 
ggregates in cubic yards. 
Fine aggregates, screen openings per inch. 
Coarse aggregates. 
0-28 
0-14 
0-8 
0-4 
0-| in. 
^j 
+a 
^j 
+i 
• 
s 
8 
i 
o 
a 
c3 
d 
a 
Size, inches. 
a 
.3 
ti 
O 
B 
B 
1 
§ 
.3 
03 
s 

1 
a 
Pm 
O 
Q 
Fq 
O 
o 
£ 
O 
O 
Mh 
O 
o 
Ph 
o 
No. 4 screen to }: 
Proportions 
i 
1.3 
2.4 
1 
1.6 
2.4 
l 
1. 8 2. 3 
1 
2.0 
2 3 
1 
2.7 
1.5 
Quantities 
1.96 
.37 
.69 
1.85 
.44 
.66 
1.82 
•4S .62 
1.75 
.52 
.59 
1.79 
79 
.40 
No. 4 screen to 1: 
Proportions 
1 
1.3 
2.7 
I 
1.6 
2.6 
1 
1.8 2.6 
1 
2.0 
2.5 
1 
2 6 
l.S 
Quantities 
1.90 
.36 
. 76 
1.77 
.42 
.68 
1.72 
.46 .66 
1.67 
.50 
.62 
i n 
fifi 
.46 
No. 4 screen to 1!: 
Proportions 
1 
1.2 
3.1 
1 
1.6 
3.2 
1 
1.7 3.1 
1 
2.0 
3.0 
i 
? 4 
2.4 
Quantities 
1.82 
.32 
.81 
1.68 
.40 
.79 
1.63 
.n .::» 
1.61 
.47 
72 
1.62 
.57 
No. 4 screen to 2: 
1 
Proportions 
1 
1.2 
3. 5 
1 
1.5 
3.5 
1 
1.6 3.7 
1 
1.9 
3 fi 
1 
2.2 
3.1 
Quantities 
1. 75 
.31 
.90 
1.68 
.36 
.85 
1.55 
.36 
.85 
1.52 
.43 
.81 
1 . 53 
. 50 
.70 
5 Tablo prepared by A. N. Johnson, based on results or investigations by Prof. 1>. A. 
Abrams, Structural Materials Research Laboratory, Lewis institute, Chicago, 111. 
