Z BULLETIN 1077, U. S. DEPARTMENT OE AGRICULTURE. 
struction should be careful to keep themselves informed regarding 
results obtained by others engaged in similar work, and by laboratory 
experiments. 
The earliest concrete pavement in the United States of which there 
is reliable record was constructed at Bellefontaine, Ohio, in 1893 and 
1894. This pavement, which contains 4,400 square yards, was con- 
structed in two courses and in squares similar to those employed in 
concrete-sidewalk construction. Prior to 1909 the total area of con- 
crete pavements was comparatively small, and in most cases these 
pavements were frankly regarded as experiments. During 1909 the 
road officials of several communities concluded that the results already 
obtained were sufficiently encouraging to warrant them in undertak- 
ing the construction of concrete pavements on a larger scale, and since 
that time a large mileage has been completed. Wayne County, Mich., 
was one of the first communities to adopt this form of construction, 
and at present probably has a greater mileage of roads paved with 
concrete than any other county in the United States. 
The majority of the concrete pavements which have been construct- 
ed have proved entirely satisfactory where traffic conditions were not 
unduly severe, and their use has increased rapidly. This is evidenced 
by the following tabulation, showing the approximate number of 
square yards of such pavements that have been placed under con- 
tract in the United States each year beginning with 1909, and the 
total constructed prior to 1909 : i 
Concrete pavement constructed or under contract in the United States. 
Year. 
Roads. 
Streets. 
Alleys. 
Totals. 
Prior to 1909 
Sq. Yds. 
34, 061 
32, 626 
151, 148 
291, 077 
1, 869, 486 
3, 339, 185 
10,008.421 
12,050,909 
15, 906, 801 
15, 333, 087 
12. 990, 519 
41 , 335, 342 
29, 326, 689 
Sq. Yds. 
444, 864 
325, 158 
6S2, 637 
1,011,440 
3,326,029 
3, 946, 219 
4, 830, 604 
5, 933, 879 
7, 395, 975 
5, 238, 062 
3, 295, 817 
11,086,419 
8, 814, 782 
Sq. Yds. 
112, 491 
86, 825 
107. 874 
136, 674 
185, 703 
30S. 365 
300, 138 
612, 921 
880, 179 
1, 200. 030 
585, 948 
1,038,173 
907,164 
Sq. Yds. 
591 416 
1909 
444, 609 
1910 
941 j 659 
1911 
1,439 191 
1912 
5, 381, 218 
1913 
7, 593 769 
1914 
15, 739, 163 
18, 575, 709 
1915 
1916 
24, 182, 955 
1917 
21,771,179 
1918 
1 6, 872 284 
1919 
53, 459, 934 
39,048 635 
1920 . 
Total to .Tan. 1, 1921 
143, 269, 351 
56, 331, 885 
6, 465, 485 
206,063.721 
The principal advantages which concrete pavements possess may 
be briefly stated and commented upon as follows : 
1. As far as can be judged, they are durable under ordinary sub- 
urban and rural traffic conditions. 
