Asphalt character

In industry, the elimination of asphaltenes from oil involves using propane or butane. The utilization of a lighter paraffin results in the heavier paraffins precipitating along with the asphaltenes thereby diminishing their aromatic character. The oil removed from its asphaltene fraction is known as deasphalted oil or DAO. The precipitated portion is called asphalt. 

Asphalt (bitumen) also occurs in various oil sand (also called tar sand) deposits which occur widely scattered through the world (17) and the bitumen is available by means of various extraction technologies. A review of the properties and character of the bitumen (18) suggests that, when used as an asphaltic binder, the bitumen compares favorably with specification-grade petroleum asphalts and may have superior aging characteristics and produce more water-resistant paving mixtures than the typical petroleum asphalts. 

As this ratio increases so does the gel character of the asphalt cement, and its coUoidal stabiUty increases. The properties of the asphalt (softening... 

Sealing and hydrophobic additive Providing waterproof character Fats, oils, wax, asphalt, sugar... 

The character of fuel oil generally renders the usual test methods for total petroleum hydrocarbons (Chapters 7 and 8) ineffective since high proportions of the fuel oil (specifically, residual fuel oil) are insoluble in the usual solvents employed for the test. In particular, the asphaltene constituents are insoluble in hydrocarbon solvents and are only soluble in aromatic solvents and chlorinated hydrocarbons (chloroform, methylene dichloride, and the like). Residua and asphalt (Chapter 10) have high proportions of asphaltene constituents, which render any test for total petroleum hydrocarbons meaningless unless a suitable solvent is employed in the test method. 

Bitumen, or asphalt, and naphtha are described much as Dioscorides describes them. Maltha is a product of similar character, will take fire and burn even upon water, and can be extinguished only by earth. The uses of bitumen were for medicines for coating the inside of vessels of copper or brass for the purpose of protecting them from the action of fire for staining bronze statues as a cement instead of mortar for buildings, as in the walls of Babylon for varnishing iron and the heads of nails to prevent their rusting. 

Values of VGC near 0.800 indicate an oil of paraffinic character (see paraffin), values close to 1.00 indicate a preponderance of aromatic structures. Like other indicators of hydrocarbon composition (as opposed to a specific laboratory analysis), VGC should not be indiscriminately applied to residual oils (see bottoms), asphaltic materials, or samples containing appreciable quantities of non-hydrocarbons. See Saybolt Universal Viscosity, specific gravity. 

In addition, the crude oils available today to the refinery are quite different in composition and properties to those available some 30 years ago (Swain, 1998 Speight, 1999). The current crude oils are somewhat heavier insofar as they have higher proportions of nonvolatile (asphaltic) constituents. In fact, by the standards of yesteryear, many of the crude oils currently in use would have been classified as heavy feedstocks, bearing in mind that they may not approach the definitions used today for heavy crude oils. Changes in feedstock character, such as this tendency to heavier materials, require adjustments to refinery operations to handle these heavier crude oils to reduce the amount of coke formed during processing and to balance the overall product slate. 

In figure 4 we can observe the variations of stiffness modulus versus temperature at 6% bitumen. As it can be seen, the waste rubber reinforcement can cause better characters in asphaltic samples. 

According to this experimental work, the waste rubber reinforcement can obviously improved characters of asphaltic samples. As stability, creep tests indicated that reinforcement by waste rubber reduced their permanent deformation significantly, it means that waste rubber provides a strong eomposite for designing mixes to avert both pavement rutting and low temperature cracking in order to prolong road life. 

Crushed waste plastics may be utilized as a base materials in road. But, the utilization is unrecommendable, because the characters of plastic do not become effective there. It will be desirable that plastics which is organic are used together with an asphalt which is organic. 

At this stage the asphalt is frequently and incorrectly referred to as pitch and has a softening point (ASTM D-36, ASTM D-61, ASTM D-2319, ASTM D-3104, ASTM D-3461) related to the amount of oil removed and increasing with increasing overhead removal. In character with the elevation of the softening point, the pour point is also elevated (Table 15.1) The more oil distilled from the residue, the higher the softening point. 

Thus elemental analysis is still of considerable value to determine the amounts of elements in asphalt, and the method chosen for the analysis may be subject to the peculiarities or character of the feedstock under investigation and should be assessed in terms of accuracy and reproducibility. The methods that are designated for elemental analysis are ... 

The term bitumen (also, on occasion, referred to as native asphalt and extra heavy oil) includes a wide variety of reddish-brown to black materials of semisoUd, viscous to brittle character that can exist in nature with no mineral impurity or with mineral matter contents that exceed 50% by weight. Bitumen is frequently found filling pores and crevices of sandstone, limestone, or argillaceous sediments, in which case the organic and associated mineral matrix is known as rock asphalt. 

Many other polymeric additives are used in butyl and PIB adhesives and sealants. Most worthy of mention are factice, which can lower cost, improve processing, and reduce stringing amorphous polypropylene, which can reduce cost and improve processing as well as impart thermoplastic character various waxes, which function in much the same manner as amorphous polypropylene and asphalt, again for lower cost. 

Mastic sealants are based upon bitumen and asphaltics, which are by-products of petroleum refining. The materials are semisolid or very viscous liquids and contain a variety of polymeric materials. Because of their hydrocarbon character, they can be expected to wet most substrates. However, because of their lack of any other functionality, they can be expected to dewet under moist conditions. This type of sealant has been used on roadways, some constmction sealing, and for pipes and marine sealants. 

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