DUST PKEVENTIOlSr AND ROAD PEESERVATION, 1915. H 



Immediately after the mixture was cooled sufficiently to avoid 

 " waving, " it was roUed with an 8-ton tandem roUer. A seal coat of 

 approximately one-half gallon of fluxed native asphalt A to the square 

 yard was then appMed by hand pouring pots, as described in experi- 

 ments Nos. 1 and 2. Sandstone chips approximately free from dust, 

 as indicated in the mechanical analjrsis of Table 7, were then spread 

 uniformly in sufficient quantity to ffil the superficial voids, and broomed 

 with rattan brooms while the roller worked. A slight excess of chips 

 was appUed, which soon broke up into fine particles under traffic. 



Experiment No. 4. — Bituminous Macadam (Mixing Method); Sandstone with 



Oil-Asphalt X. 



Location: Station 28+10 to station 38+10. 

 Total length: 1,000 feet. 

 Total area: 1,924 square yards. 



This experiment was exactly similar to experiment No. 3, except 

 that oil-asphalt X of properties shown in Table 8 was used instead of 

 fluxed native asphalt. The maximum grade on this section is 4.92 

 per cent. 



Experiment No. 5. — Bituminous Macadam (Penetration Method); Gneiss 

 wrTH Fluxed Native Asphalt A. 



Location: Station 38+10 to station 50+45. 



Total length: 1,235 feet. 



Total area: 2,196.6 square yards. 



This experiment was exactly similar to experiment No. 1, except 

 that '^H-inch" gneiss was used instead of sandstone. The mechan- 

 ical analysis of the crushed gneiss is shown in Table 5 and the phys- 

 ical properties of the stone in Table 4. The mechanical analysis of 

 the chips used is shown in Table 7. The chips broke up into fine 

 particles under traffic. 



Experiment No. 6. — Bituminous Macadam (Penetration Method); Gneiss 



WITH Oil-Asphalt X. 



T/Ocation: Station 50+45 to station 58+45. 



Total length: 800 feet. 



Total area: 1,422.2 square yards. 



ThLs experiment was exactly similar to experiment No. 5, except 

 that oil-asphalt X was used instead of fluxed native asphalt. 



