36 BULLETIN" 257, U. S. DEPARTMENT OF AGRICULTURE. 



on the edges, particularly the north edge, and there are indications 



that the bituminous material is losing its life. A pothole is forming 



just south of the center and on the west side of a patch at station 



13+23. 



Experiment No. 6 (Oil Asphalt — Penetration Method). 



This section continues in good condition, except for the fact that 

 the seal coat seems to be wearing, while it is nearly gone on a strip 

 about 2 feet wide 8 or 9 feet in from the south side from station 

 13 + 94 to station 14 + 38. The bituminous material of the seal coat 

 over this area seems to lack life, and indications are that the strip 

 will extend to the eastward. There is a narrow strip south of the 

 center where the seal coat has been picked up by the wheels of some 

 heavily loaded vehicle. 



Experiment No. 7 (Repined Coal-Tar — Penetration Method). 



The general condition of this section is good. The surface is very 

 satisfactory in the center, but along the sides the seal coat appears 

 thin and is gradually disappearing. There is a bad depression on 

 the north side at the junction of experiments Nos. 6 and 7, and three 

 potholes were observed to be developing along the south side at 

 stations 16 + 03, 16+15, and 16 + 94, respectively. The patch pre- 

 viously made over the conduit across the roadway is in excellent 

 condition, but where one was made at station 16 + 90 near the south 

 edge of the roadway the surface is below grade. Other than as 

 above noted, the condition of this experiment remains about the 

 same as when inspected, in December, 1913, 



Experiment No. 8 (Fluxed Native Asphalt — Penetration Method). 



This section is in about the same condition as reported in U. S. 

 Department of Agriculture Bulletin No. 105, with the exception that 

 a slight waviness has developed over the entire roadway. This is 

 more noticeable at the sides, where the excess of bituminous material 

 used in the original construction has pushed out. 



Experiment No. 9 (Oil Asphalt — Penetration Method). 



The surface of this experiment is in good condition, with the ex- 

 ception of a few spots where the seal coat has been picked up or 

 worn off, and these have partially healed over. Some would not be 

 noticeable except on a rainy day. From station 19 + 20 to station 

 19 + 34 the seal coat has been worn off in the center of the road. 

 From station 19 + 34 to the east end of the experiment there is a 

 narrow strip where the seal coat was partially stripped off by the 

 L wheel of some heavily loaded vehicle. 



There are some waves on the edges and a small hump on the south 

 side at about station 18 + 54. The work done to fill in between this 

 section and the wood-block pavement east of the experiment is in 



