DUST PREVENTION AND ROAD PRESERVATION. 29 



Table 31. — -Materials and cost data for experiments at Miami, Fla. 









Quantities of 













Description. 





materials (per 

 square yard). 



Cost 



per square yard. 





6 







o 



a 









t* 



fl 







3 



fl 



oj 





K 





C3 



w 



o 



















tfl 







1 



Material and method. 



1-2 



o 



-fl£ 



o 



M 

 o 



o 



d 

 Fl 





fl o 



o © 

 ft 



fl 



CD 



Fl 





la 



fl * 



fa 



fl M) 



03 .5 



tuolfl 



pi .a 



M 



o 



o 



c 





H Cu 





c9 



is 



a 



T3 



R< 



& 



_g 





a 



3 



fl 



03 



































H 





Q 



a 



< 



'A 



pq 



m 



P4 



£ 



P4 



CO 



< 



rt 



e 



EH 











Sif. 



Cm. 



Gal- 



Cu. 

























Feet. 



yds. 



yds. 



lons. 



yds. 



Cfe. 



tts. 



Cto. 



CTs. 



Cts. 



Cts. 



CTs. 



Cts. 



1 



Light asphaltic pe- 

 troleum (semi- 

 penetration). 



Cold.. 



96 



213 





0.92 



0.012 



2.34 





14.90 



1.33 



2.23 



1.01 



0.98 



22.79 



2 



Light asphaltic pe- 



...do... 



453 1,( ■ 





.41 



.012 



2.34 





6.66 



1.33 



1.01 



1.01 



.98 



13.33 





troleum (surface 

































treatment). 































3 



Heavy asphaltic pe- 

 troleum (pene- 

 tration method). 



Hot... 



199 



443 



0. 069 



.625 



.012 



2.34 



11.01 



11.37 



1.33 



1.52 



1.01 



.98 



29.56 



4 



Light asphaltic pe- 

 troleum (pene- 

 tration method). 



Cold.. 



168 



371 



.069 



.705 



.012 



2.34 



11.01 



11.42 



1.33 



1.71 



1.01 



.98 



29.80 



S 



Heavy asphaltic pe- 

 troleum (pene- 

 tration method). 



Hot... 



239 



531 



.041 



.62 



.012 



2.34 



6.61 



11.28 



1.33 



1.51 



1.01 



.98 



25.06 



6 



do 



...do... 



107 



240 



.087 



.99 



.012 



2.34 



16.67 



18.02 



1.33 



2.42 



1.01 



.93 



42.77 



SUPPLEMENTARY REPORT OF EXPERIMENTS MADE AT WASHINGTON, 



D. C, 1912. 



TAR PREPARATION AND OILS— SURFACE TREATMENT. 



The original report of these experiments is to be found in Circular 

 No. 99, and the following covers the repairs to date, and the condi- 

 tion of the various sections in January, 1914. 



Section No. 1. — Refined water-gas tar preparation. 



This section presents a smooth, hard, mosaic surface and has not 

 required any repairs. In a few places along the sides of the road 

 the treatment has cracked off for a few inches back from the edge, 

 exposing the underlying macadam. 



Section No. 2. — Asphaltic petroleum. 



This treatment showed some tendency to push into slight waves 

 and a few small humps, particularly along the south edge of the 

 roadway. Several worn depressions in the middle of the road also 

 developed during the winter, and apparently had their initial cause 

 in the fact that small dust patches had been overlooked in cleaning 

 the surface, and the treatment had not adhered properly. At the 

 east end of the section, a number of steam pipes pass under the road, 

 and the heat from these gives rise to conditions under which it has 

 always been difficult to maintain a satisfactory road surface. Three 

 distinct displacements of the surface have taken place at this point, 



