38 BULLETIN 105., T. S. DEPARTMENT OE AGBrCTJLTTJKE. 



to a uniform grade. The road was then well rolled. A seal coat of 

 refined coal tar, the analysis of which is given in Table 35, was then 

 applied at the rate of 0.53 gallon per square yard, covered immediately 

 with f-inch stone at the rate of 0.024 cubic yard per square yard, 

 and thoroughly rolled. The f-inch stone used was rather dirty, owing 

 to having been handled from the ground several times. 



When inspected in December, this section was found to be in 

 worse condition than before it had been scarified. Short, choppy 

 waves had developed, from 3 to 4 feet in length and from 4 to 5 

 inches deep, from crest to trough. A somewhat wavy condition 

 had also developed on the north side from station 4 + 50 to station 

 5 + 00. 



Experiment Xo. 3. — Fluxed native asphalt — Mixing method. 



In o repairs were made to this section and when inspected in Decem- 

 ber it was still found to be in very good condition. There was a 

 slight indication of waviness, but the undulations were long and 

 shallow, and not sufficiently pronounced to inconvenience automo- 

 bile traffic. 



Experiment Xo. 4. — Refined coal tar — Mixing method. 



Xo repairs were made to this section and when inspected in Decem- 

 ber it was reported as being generally in good condition. The sur- 

 face from station 8 + 00 to station 8 + 70 was very smooth, but some 

 waviness had developed along the outer one-third of the roadway. 

 On the south side this was apparently due to bleeding, and the 

 excess material had been worked outward into waves which were 

 in no place, however, more than 2 inches in depth. The earth 

 shoulders along the brick gutters throughout this portion of the 

 pavement had been much eroded, and the water from the road 

 surface and cross streets does not flow in the gutter but along the 

 shoulder of this section. From station 8 + 70 to station 9 + 50 the 

 surface condition is very good and presents a somewhat mottled 

 appearance, with about one-half mosaic and one-half covered with 

 bitumen. From station 9 + 50 to the end of the section, where the 

 oil-asphalt seal coat was applied, the surface resembled sheet asphalt. 

 This portion was becoming a trifle wavy about midway between the 

 sides and crown of the roadway. 



Experiment Xo. 5. — Cut-back oil asphalt — Mixing method. 



In June the general surface of this section was good except that 

 it had waved slightly on the sides and holes had been worn through as 

 follows: Station 11 +65, 2\ * feet by 2\ feet at the north edge of the 

 pavement : station 11+ 68, 2 feet by 2\ feet, 5 feet from the south edge 



1 Size of hole after it was trimmed out for repairing. 



