DUST PREVENTION AND ROAD PRESERVATION. 39 



oi the pavement; station 11+ 80, 1^ feet by 2 feet, 7 feet from the south 

 edge of the pavement; station 12 + 20, 2 feet by 2 feet, 7 feet from 

 the south edge of the pavement; station 12 + 48, 3 feet by 3 feet, 



17 feet from the south edge of the pavement; and station 13 + 67, 

 If feet by If feet, 17 feet from the south edge of the pavement. 



These holes were repaired by first digging out the wearing course 

 and base to a depth of 4 niches. They were then filled with 1 f-inch 

 stone, and the voids of the stone were partially filled with sand 

 and tamped by hand. The refined coal tar referred to in Table 35 

 was then applied, covered with f-inch stone, tamped by hand, and 

 rolled with a steam roller. 



When inspected in December it was found that two holes about 



18 inches in diameter had worn almost through the thickness of the 

 wearing surface. These were located on the north side of the road 

 at station 11+6 and station 11+22, respectively. Between station 

 11+00 and station 11+50 a bad wavy condition had developed on 

 the north side of the road, but only to a slight extent on the south 

 side. The center of the roadway was in very good condition. Sev- 

 eral of the patches were low and all were in need of a seal coat, but 

 the patch made with Topeka mixture was in excellent condition". 



At Hardenbrook Avenue the south side of the intersection was more 

 wavy than any other section of the experiments, excepting experi- 

 ment No. 2, but the north side of the intersection was in very fair 

 condition. 



Experiment No.. .6. — Oil asphalt — Penetration method. 



No repairs were made to this section and it continues in excellent 

 condition. Two grades of oil asphalt were originally used for a seal 

 coat on this experiment^ and the relative wearing qualities can now 

 be noted. Where the heavier grade of material was used, the seal 

 coat remains practically intact and only an occasional stone is visible. 

 Many more stones of the wearing course can be seen where the lighter 

 grade of the oil- asphalt seal coat was used. 



Experiment No. 7. — Repined coal tar — Penetration method. 



In June this section was in good condition excepting that the fol- 

 lowing holes had worn through: Station 15 + 51, 3^ feet by 3 J feet, at 

 the north edge of the pavement; station 16 + 90, 1 foot by 4 feet, 1 

 foot from the south edge of the pavement; and station 16 + 95, 1 foot 

 by If feet, 1 foot from the north edge of the pavement. These holes 

 were repaired in the same manner as those in section No. 5. 



In December the section was reported as in good condition except- 

 ing for a raveled spot at station 16 + 50. 



Experiment No. 8. — Fluxed native asphalt — Penetration method. 



No repairs were made on this section, and at the December inspec- 

 tion it was in good condition. 



