Sulfur content asphalt

Trinidad asphalt has a relatively uniform composition of 29% water and gas, 39% bitumen soluble in carbon disulfide, 27% mineral matter on ignition, and 5% bitumen that remains adsorbed on the mineral matter. Refining is essentially a process of dehydration by heating the cmde asphalt to ca 165°C. The refined product averages 36% mineral ash with a penetration at 25°C of about 2 (0.2 mm), a softening point (ring and ball method) of 99°C, a flash point (Cleveland open cup) of 254°C, a sulfur content of 3.3%, and a saponification value of 45 mg KOH/g. The mineral matter typically contains... 

All crudes are a variation of the hydrocarbon base CH2. The ultimate composition shows 84 to 86% carbon, 10 to 14% hydrogen, and small percentages of sulfur (0.06 to 2%), nitrogen (2 %), and oxygen (0.1 to 2%). The sulfur content is usually below 1.0% but may be as high as 5.0%. Physically crude oil may be water-white, clear yellowish, green, brown, or black, heavy and thick like tar or asphalt. 

The effect of sulfur and asphalt contents in SAS mixtures on Marshall Stability is shown in Figure 3 [15]. The stability values tend to increase with sulfur content but decrease with asphalt addition. It is interesting to note that without the sulfur and asphalt, sand mixes would have little or no stability. The data also indicate a wide variety of mix designs are possible whose stabilities are consistant with Asphalt Institute suggested values for conventional asphaltic mixes. 

Figure 3. Marshall stability as a function of sulfur and asphalt contents in sand-asphalt-sulfur mixes (15,). Materials used were medium-coarse sand and 150/180 pen. asphalt. All specimens were prepared with 2 hammer blows on one face only.

Figure 5. Fatigue life as a function of sulfur content for a sand-asphalt-sulfur mix. Test temperature 50°F (10°C). Test frequency 60 Hz. Materials medium-coarse sandt and 150/180 pen. asphalt. Asphalt content 6% wt (15),...

The emulsifying equipment has been set up as a self-contained trailer-mounted unit. The unit used at the 1975 field trial in Lufkin, Texas is designed to accept molten sulfur and hot asphalt from road tankers. The sulfur and asphalt flow rates are controlled by two proportioning pumps driven by a sprocket and chain arrangement from a common shaft. This arrangement enables the sulfur content of the binder to be varied from 20% to 50%. 

Commercial value of a petroleum liquid can be estimated quickly through measurement of the following physical characteristics . specific gravity, gasoline and kerosene content, sulfur content, asphalt content, pour point, and cloud point. 

Marshall stability of asphalt concrete dropped 72% after immersion testing in gasoline compared with only a 21% loss with 35-vol % sulfur-asphalt concrete. Jet and diesel fuels had a lesser effect on the Marshall stabilities than did gasoline. The solvent effect on sulfur-asphalt concrete materials decreased with increasing sulfur content in the asphaltic binder in the O-35-vol % substitution range. The greater resistance of sulfur-... 

Thermopave mix (medium sand)—asphalt content, 6 wt % sulfur content, 13 wt % Plant, Cedarapids capacity, 6000 lb (2722 kg) batch batch size evaluated, 5000 lb (2268 kg) mixing time, 25 sec with sulfur. 

Examination of thick sulfur-extended binder films, mixed with sulfur for 30,45, and 60 sec, showed the presence of some larger sulfur particles. As the particle density on the slide is higher in thick films, this demonstrates that some coagulation of the sulfur particles takes place if the sulfur content is too great, relative to the amount of asphalt (sulfur/ asphalt weight ratio, 0.33). Similar evidence of coagulation of particles was obtained in thick films taken from the laboratory Waring blender dispersion for a similar blend. 

Thermopave mixes use substantially higher sulfur contents. Microscopic examination of mixes prepared in the laboratory and in a commercial Cedarapids hot-mix plant verified that some of the sulfur is finely dispersed, therefore contributing to the dilution of the asphalt, but most of the sulfur agglomerates readily to perform as a mix stabilizer. 

Based on studies performed, some guidelines have been formulated for the design of sulfur-extended binder mixes. These include recommendations for limiting sulfur content to maintain existing mix flexibility and the replacement of asphalt with sulfur on an equivalent volume basis to maintain the existing standard of mix durability. 

Sulfur contents may be expressed either on a weight or volumetric basis. The binder consisting of asphalt cement and sulfur may be expressed also as a percentage of the VMA, and the amount of sulfur may be expressed as vol % of the binder. The symbol used for wt % is w/o, whereas that used for vol % is v/o. Whichever basis of expression is used, it should be remembered that the specific gravity of sulfur is approximately twioe that of asphalt cement, and therefore will occupy about half the space of an equivalent weight of asphalt cement. Asphalt cement and sulfur contents reported here were based upon wt % of total mix. 

Type Aggregate in Mix Asphalt Content (w/o) Sulfur Content (w/o) Resilient Modulus X (psi)... 

The conventional approach to asphalt analysis has been to extract the bitumen with an organic solvent and then to characterize bitumen and minerals separately. Sulfur content and melting point are commonly measured properties of bitumen. Minerals are generally screened and then subjected to simple quantitative tests. Measurement of weight loss on ignition helps to distinguish between calcium carbonate, which loses... 

Analyses of a series of asphalts from layers spanning more than a millennium at the single site of Eshunna are presented in Table III. All nine samples were analyzed by Forbes and the seven largest by Nellen-steyn (4) as well. The asphalts averaged 19-36% bitumen (a little less than in Table II) and about 10% vegetal matter. Sulfur contents of the bitumens were more consistent than in Table II with only two exceptions for Forbes (D and H) and one for Nellensteyn (5), all were 7.3 1.0%. Minerals content of the bitumens was 5.5 2.5%. The ratio of carbonate to silica was 2 1 to 4 1 except for samples A (and 1) and C (and 3) in... 

These analyses support a significant series of inferences with respect to the sources of asphalt. DiflEerences in asphalt composition, mineral color, and especially sulfur content of the bitumen indicate that lowland and highland asphalts were not derived from the same raw materials. Mesopotamian asphalts simply do not match those found in the usually earlier settlements along the Tigris tributaries. Presumably new sources upstream along the Euphrates were used. They would certainly be more convenient than overland shipment from the east. Lesser diflEerences... 

Partial oxidation has practically no restrictions regarding the nature of the hydrocarbon and the sulfur content. Natural gas, refinery gases, LPG, naphtha, heavy fuel, vacuum residue, visbreaker oil, asphalt, and tar can be used as feedstock. As the investment costs for partial oxidation are higher than for steam reforming, mainly because of the cyrogenic air separation, it is usually not a choice for the lighter hydrocarbons, but heavy feedstocks from fuel oil to asphalt, when favorably priced, can be a competitive option for various locations and circumstances. In some special cases, where the primary reformer is a bottleneck for a capacity increase, a small parallel partial oxidation unit based on natural gas could be installed, if a surplus of... 

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