12 
BULLETIN 532, U. S. DEPARTMENT OE AGRICULTURE. 
from the side of the 8 by 8 inch column. The curve on figure 11 was obtained 
partly by measurement and partly by theory, assuming that the deformations 
from' the reinforced side to the plain side varied as the ordinates to a straight 
line. This assumption has been shown to be true a number of times in the 
cases of beams subjected to bending stresses. Note that the steel seems to have 
had a bending effect on the specimen, the unreinforced side shrinking much 
more than the reinforced side. The amount of shrinkage on the plain side of 
the column at the end of one year amounted to approximately 0.1 per 'cent; that 
of the steel amounted to 0.03 per cent. Any such shrinkage as this would tend 
to cause compressive stresses in the concrete on the unreinforced side and ten- 
sile stresses in the concrete on the reinforced side. In a concrete pavement, 
with the reinforcement placed near the top or bottom, there would be unequal 
shrinkage at these two surfaces, thereby creating a tendency to curl and crack. 
To eliminate the unequal shrinkage in concrete pavements, due to eccentric 
i POUNDS 
.NOTE: CONCRETE DEFORMATIONS MEASUREO ON UNREINFORCED SIDE 
AGE IN DAYS 
O.00O2 
2 0-0004 
o 
k 
U 00005 
K 
£ 0-OOOfc 
o 
o 
0007 
z 
D 00006 
V 
1\ 
^ H 
ST£ 
EL 
\ 
1 
^co 
*£* 
|T£_ 
000 10 
Fig. 11. — Specimen reinforced on one side. 
placing of the steel, and at the same time to take care of settlement cracks as 
efficiently as possible, it is well to place the reinforcement in the center of the 
I pavement. 
MEASURING THE EXPANSION AND CONTRACTION OF CONCRETE 
ROADS. 
Although the laboratory measurements of expansion and contrac- 
tion of concrete gave much information on the influences affecting the 
length of a concrete road, the actual conditions of moisture in the 
load are so different from those of the laboratory that it was thought 
Avell to obtain additional information of the movements that take 
place by actually measuring the changes in the road. 
A concrete road is subjected to a great range of variables. In the 
initial stages of its hardening it generally is kept moistened arti- 
