24 



BULLETIN 532, U. S. DEPARTMENT OF AGRICULTURE. 



Measurements on Section II. 



OHIO POST ROAD AT MOSCOW BRIDGE. 



Section II was laid on a 0.4 per cent grade with limestone aggregate 

 with joints spaced successively 20, 40, GO, 80, and 100 feet apart. 

 This section, laid one month later than Section I, showed much 

 the same characteristics as far as expansion and contraction are con- 

 cerned. As the weather became colder and colder, the concrete showed 

 more and more contraction. In the hot weather of the summer one 

 year after laying the concrete showed about the same amount of 

 expansion that it showed three days after laying. One of the cracks, 

 however, that had opened in the preceding winter, instead of closing 

 because of the expansion of the concrete, remained open, probably 













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AUGUST 1 ,191-4 



NOVEMBER 2,1914 



MARCH 3.1915 



JUNE 17,1915 



rEB23.i9ia 



TEMPERATURE Or PAVEMENT 

 JULY 31- 79° r. 

 AUG. 1-73° 

 NOV 2 - 53* 

 MAR 3 - 30" 

 JUNE 17 - 70° 

 FEB 23- 37° 



Fig. 17. — Expansion and contraction of concrete, 

 Ohio Post Road. Section at Moscow Bridge. 

 Laid July 29-30, 1914. Section II. 



OAving to the presence of foreign material. This same crack opened 

 considerably wider in the cold weather of the following winter, as 

 seen in the measurements of February 25, and the remaining joints 

 likewise expanded considerably. Note that a crack formed in the 

 100- foot section and did not form in the 20, 40, 60, or 80-foot sections. 



MEasubements on Section III. 



OHIO POST ROAD AT MOUNT STERLING. 



Section III shows much the same characteristics as the preceding 

 Sections I and II. This section was laid on November 5, and the 

 initial readings were taken on November G at a temperature of 51° F. 



