122 ANNUAL REPORT 
The results obtained were as follows: 
Coefficient of expansion of gravel concrete, 0.0000054 per degree F. 
Coefficient of expansion of broken stone concrete, 0.0000055 per 
degree F. 
Coefficient of expansion of limestone bar, 0.0000056 per degree F. 
The coefficient for concrete may be conveniently remembered as “five 
zeros fifty-five.” 
As the coefficient for steel is, closely, 0.0.000060, the variation between 
steel and concrete is not sufficient to seriously affect their use in combi- 
nation. 
COST OF CONCRETE. 
There are so many conditions, local and general, that enter into the 
cost of concrete, that but brief space will be taken up here to give a few in- 
stances of the actual cost of concrete for various purposes and in widely 
different localities. The prices of labor and material and the ease or dif- 
ficulty of access to material and the work to be done, largely govern the 
cost of concrete. | 
TABLE No. 20. 
Cost of Concrete—Using Portland Cement. 
| a cs) 
g a 
, a) n 
E 3H alge : 
z 5 iis e | BS 5 
8 8 = & ge 5) 
QA H (e) Ay @) ae 
1880-85 |Newhaven, Eng. ...... Breakwater ...... 1-7 $5.50 | Laid in 
sacks. 
1889 IBLTWTR NO ING Moe wo ba oe 6 LEE RAEI Go oulloncoos acl] Doll 
1891 Butralo Ne Ve ee en Breakwater ..... ee spon eS il 
1900-02 |Buffalo, N. Y...... ....|Breakwater ...... 1-8 -4- | 5.65 
1900-02 |Buffalo, N Y........... Breakwater ..... es =f || BGA 
1890-91 |Toronto, Can........... Road Foundation .|1-2 -714| 4.83 
1895 Marquette, Mich. ...... Breakwater ...... 1-216-5 | 6.35 ; 
1899 Marquette, Mich........ U.S. Breakwater.|.........| 4.57 
Eng. News 
1889 ButtalowNyiyie oe ye Elan Orakei en been: 8.75 || Feb.17,’98. 
; Gov’t and 
1893 Gr. Kanawha, W. Va...|/RiverImprov’ment)......... 7.25 scien 
1897 Monongahela River.....\LockandDam |......... 11.00 
1898 Chicago, Ills........ .,. |/Sidewalks. ....... 1-2 -5 /|10.00 | Approx. 
