Aug. 13, 191 7 



Toughness of Bituminous Aggregates 



321 



Two grades of refined water-gas tar, X and Y, were used. The latter 

 was of the consistency used frequently in bituminous-concrete con- 

 struction, and that there might be no question about the similar character 

 of the two tars, X was prepared by adding a proper amount of heavy 

 water-gas-tar distillate to Y, producing a tar of the consistency used 

 commonly in hot surface treatment, and also in bituminous concrete in 

 some New England localities, as noted above. In addition to these two 

 tars, a residual petroleum. No. 6408, an oil asphalt. No. 6409, and a fluxed 

 native asphalt, No. 5767, were used. The characteristics of all the 

 bituminous materials are given in Tables II and III. 



TabIvU II. — Analyses of water-gas tar 



Sample No. 



X' 



Y' 



Specific gravity (25°/25° C). . . . 



Float test (32° C.) 



Float test (50° C.) 



Bitumen soluble in carbon 



per cent 



Organic matter insoluble (free 



per cent 



Inorganic matter insoluble per cent. . 



Distillate (27o°-3i5° C.) by weight, per 



cent 



Pitch (over 315° C.) by weight. . .per cent. . 



bisulphid, 

 carbon), 



I. 168 



99- 23 



o. 72 

 0.05 



I. 184 



99- 25 



o. 70 

 0.05 



I. 162 

 i'44^' 



99- 23 



0-75 

 o. 02 



13- 4 

 86.6 



I. 184 



2' 50" 

 99- 23 



o. 72 

 o. 05 



2. 48 



97-43 



Table III. — Analyses of petroleum and asphalt products 



Sample No. 



Material. 



Specific gravity (25°/25° C.) . 

 Specific viscosity (Engler 



100° C.) 



Float test (32° C.) 



Float test (50° C.) 



Melting point (° C.) 



Penetration (100 gm., 5 sec, 



25° C.) 



Loss (163° C, 5 hours) 



Float test of residue (50° C.) . 

 Penetration of residue (25° 



c.) 



Bitumen soluble in carbon 



bisulphid per cent. . 



Organic matter insoluble, 



per cent 



Inorganic matter insoluble, 



per cent 



Total bitumen insoluble in 



86° B. naphtha, .per cent. . 

 Fixed carbon per cent . . 



6408 



Residual 

 petro- 

 leum. 



47 



7'' 20'' 



l' 45" 



I. 17 

 2' 38^' 



99.96 

 o. 04 



21-35 

 11.08 



6409 



Oil 

 asphalt. 



54 



III 

 o. 62 



78 

 99.96 



o. 04 



o 

 28. 14 



13-65 



5767 



Fluxed 

 native 

 asphalt. 



1.044 



52-5 



122 

 3.08 



65 



95-54 

 1.84 

 I. 62 



22. 29 

 10. 62 



8950 



Oil 

 asphalt. 



1.036 



45-7 



145 

 o. 46 



87 



99-95 

 0.05 



25-65 

 15.26 



8949 



Oil 

 asphalt. 



I. 046 



51.8 



91 

 o. 16 



55 



99.92 

 o. 06 

 o. 02 



29-47 



17. 60 



8948 



Oil 

 asphalt. 



1. 048 



6a. 4 



5° 

 o. 09 



37 



99.84 



o. 10 



o. 06 



29. 76 

 18.05 



8748 



Fluxed 

 native 

 asphalt. 



1.050. 



44 



118 

 I. 16 



65 



95-6^ 

 1. 12 



3- 19 



24.32 

 12. 52 



