Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
  • C10C1/00—Working-up tar
  • C10C1/005—Working-up tar by mixing two or more coaltar fractions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61C—DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE
  • A61C8/00—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools
  • A61C8/0018—Means to be fixed to the jaw-bone for consolidating natural teeth or for fixing dental prostheses thereon; Dental implants; Implanting tools characterised by the shape
  • A61C8/0028—Pins, needles; Head structures therefor
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
  • C10C3/00—Working-up pitch, asphalt, bitumen
  • C10C3/005—Working-up pitch, asphalt, bitumen by mixing several fractions (also coaltar fractions with petroleum fractions)

Definitions

• This invention relates to improved coal tar compositions adapted for use as paving binders, and to a process for preparing them.
• Bituminous materials have been used for many years in the preparation of road paving compositions to bind mineral aggregate in the roadbed or other paved areas and to present a smooth and durable wearing surface for traffic.
• the most widely used are the asphalts, derived as residues from asphaltic petroleumisi.
• the petroleum asphalts are normaly solid, or semi-solid bitumens, which are usually applied to the road or other similar surface or to mineral aggregate either in the hot molten state or as solutions in volatile solvents.
• Such compositions then set or solidify, either rapidly, by cooling or, more slowly, by evaporation of the volatile solvent, thus producing firm surfaces which are little affected by temperature changes which occur in normal outdoor exposure, resulting in surfaces possessing low temperature suceptibilities.
• the petroleum asphalts in general, however, suffer both from poor initial wetting power for the mineral aggregate used in pavement construction which results in poor binding of the aggregate mass.
• asphaltic bitumens are completely soluble in petroleum oils and greases and, thus, surfaces composed of such binders suffer serious damage when exposed to such petroleum products, as for example, to jet fuel, gasoline or motor oil and the like.
• bituminous paving binders are certain tarry residues obtained in the distillation of crude tars resulting from the destructive distillation of bituminous coal, the principal source of such tar being the by-product coke ovens producing metallurgical coke. Such residues may be, and usualy are, cut back or fluxed, before use, with coal tar distillates to meet the required specifications for the desired type of tar. Standard road tars are customarily prepared in fourteen different grades, which are essentially similar except for differences in consistency or viscosity, the variety of grades being provided so that material may be chosen to meet local conditions of temperature, road conditions, climate, etc. Specifications for such tars are given in ASTM specification D-490.
• the lower numbered grades RT-l, RT-2, RT-3 and RT-4 are relatively low viscosity tars used in general in prime coat application and light surface treatment of pavements; RT-S and RT-6 are of somewhat higher consistency and serve for use in surface treatment and road mix; RT-7, RT-8 and RT9 of still higher consistencies, are useful in surface treatment, road mix, plant mix and seal coats, these latter grades being the most Widely used and representative grades of road tars; RT-lt), RT-ll and RT-12 of even higher consistencies are for use in surface treatment, plant mix, penetration, crack filler and seal coat adjations, while the special grades RT CB5 and RT CB-6 of consistencies similar to the RT-S and RT6 grades but somewhat quicker setting, are used in patching, surface treatment and also for plant mix and road mix where low temperature application and quick setting are desired.
• coal tar derived road tars have superior wetting power for mineral aggregate and are extremely resistant to both water and to petroleum oils and greases.
• the coal tars however, lack the low temperature susceptibility of the petroleum asphaltic bitumens, and tend to flow and bleed out of the aggregate when used in paving construction.
• the asphalt type binders uesd in road and similar constructions are essentially non-volatile and are ordinarily applied as hot melts or as solvent solutions. When hotapplied, these materials set by cooling and undergo no further change in physical characteristics. When applied as a solution in a solvent the binder cures by solvent evaporation and leaves a residual film of the non-volatile asphalt.
• coal tar binders in contrast, are composed of a multiplicity of components with varying degrees of volatility. Although often heated to increase fluidity for application, they are not initially solid at normal temperature, and harden or cure by the slow progressive evaporation of the more volatile portions of the tar itself. When attempts are made to hasten the curing time by increasing the amount of the more volatile component there must also be an increase in the hard non-volatile component if the desired viscosity is to be retained.
• the non-volatile pitch constituents of coal tar have a high temperature susceptibility and thus such a blend, while having a satisfactory cure rate will leave a residual binder highly susceptible to changes in consistency with changes in temperature.
• An object of the present invention is to provide a paving composition composed entirely of coal tar derived components, which has an unusually low temperature susceptibility and an exceptionally fast rate of curing when applied to road or other surfaces.
• compositions of my invention comprising mixtures of normal road tars with between about 25% and about by volume of an oxidized aromatic flux oil residue, as hereinafter defined, fluxed with sufiicient quantities of a coal tar distillate fiuxing oil to meet the requirements of ASTM specifications D-490.
• coal tar paving compositions of my invention are suitable for use in all types of paving applications, for example, in the preparation of bituminous macadam, bituminous concrete, in cover coats and in the preparation of the so-called black bases.
• Black bases are pre-mixed blends of run-ofbank gravel of the desired size, with bituminous paving compositions. Such bases are applied alone or in combination with penetration macadam to the sub-base of the area to be paved.
• black bases have been found to yield economic advantages in that they require lower coat thicknesses to provide the same load bearing capacity, than are required of the standard penetration macadam or bituminous concrete.
• the greater the load bearing capacity of the black base the thinner the layer that can be applied to produce the same durability in the paving.
• These black bases are customarily stock piled at the job site in advance of starting construction so that for such black bases, it is important that the tar used in their preparation be selected to preserve the workability of the base over the period of storage.
• the paving compositions of my invention all have unusually low temperature susceptibilities, fast curing rates, and yield residues of controlled high softening points.
• Temperature susceptibility refers to the change in consistency of the composition with temperature.
• a composition which is hard at low temperatures may soften rapidly as temperature is raised.
• Such a composition is said to have a high temperature susceptibility.
• a composition with a low temperature susceptibility will not soften as rapidly with rises in temperature and will not harden as rapidly with reductions in temperature.
• This susceptibility to changes in consistency with tempera ture may be rated by the correlation of the needle penetration at a given temperature, usually at 77 F., to the ring and ball softening point of the bitumen.
• a nomograph is provided relating penetration to ring and ball softening temperature, from which a penetration index value may be derived which is a valuable index of temperature susceptibility of the bitumen.
• the temperature susceptibility scale as shown in the publication ranges from minus 10 to plus 20. An index of +20 would indicate zero temperature susceptibility. With increasing susceptibility the index decreases through to 10, the latter value corresponding to an infinitely large susceptibility. Thus the lower the penetration index, the higher is the temperature susceptibility of the bitumen.
• Penetration indexes of normal coal tar based road tars meets the ASTM specifications usually range substantially below -1.5 usually close to -2, and hence are rated as having high temperature susceptibility, i.e., poor resistance to temperature change.
• the penetration index is significantly raised to values above 2.0, usually to values between about 1.5 and about 1.0 or higher.
• curing rate refers to the rate of gradual hardening or setting of the tar, after application to the surface, which takes place by evaporation of volatile matter in the tar. This rate depends on a number of factors, including the relative proportions of components of different boiling points, ambient temperatures during the successive stages of cure, etc. A rapid cure to the consistency required to minimize bleeding or flow and to sustain traffic is desirable.
• ASTM specification D- 490 requires that the residue produced by distilling the road tar to 300 C. according to ASTM test method D-20 shall have a ring and ball softening point between 30 C. and 70 C., the tars of higher residue softening point values being the faster curing.
• the precise range varies slightly for the different grades of tar.
• the majority of road tars have residue softening points of around 40 to 45, and thus have relatively low curing rates. While it is possible to produce a normal road tar having high residue softening points up to the 70 C.
• the tars of the present invention have residue softening points in the upper portion of the ASTM-D-490 specification range, i.e. between about 50 C. and about 70 C. and still provide residues having a low degree of temperature susceptibility as pointed out above.
• residue softening points in the upper portion of the ASTM-D-490 specification range, i.e. between about 50 C. and about 70 C. and still provide residues having a low degree of temperature susceptibility as pointed out above.
• the tars of my invention possess concomitantly the two heretofore-considered paradoxical properties of fast cure and low temperature susceptibilities rendering them of exceptional value particularly in a number of specialized applications as brought out above.
• This test involves applying a uniform, thin film of the tar of standard thickness, usually 0.032 inch, to a plane surface, and subjecting the films to simulated aging conditions by exposure to 50 C. (122 F.) temperature under forced air circulation conditions, and measuring the ring and ball softening points of the films at successive intervals. In this way a definitive and substantially reliable comparison of relative curing times of different tars can be obtained.
• the oxidized aromatic flux oil residue which is the critical component of the new paving tars of my inven tion, is obtained by subjecting a selected coal tar flux oil to intimate contact with a gas containing elemental oxy" gen, for example air, at temperatures between about 200 C. and about 500 C. for a time sufficient to produce an oxidized fiux oil residue containing at least about 15%, preferably between about 15% and about 45% by weight of benzol-insoluble compounds, usually about 30%.
• the oxidized aromatic flux oil residue is a pitch-like material having a ring and ball softening point between about 50 C. and about 135 C., preferably between about 60 C. and about C. and a Penetration Index between 0 and 1.5, usually about -0.5.
• the oxidized product has a specific gravity, Sp. Gr. 25/ 25 C., between 1.20 and 1.25, usually about 1.22.
• the flux oil after oxidation no longer is an oil but has substantially the characteristics of a pitch. Blowing the flux oil under the above conditions gives rise to formation of benzol-insoluble compounds which are believed to be responsible for the improved characteristics of reduced temperature susceptibilities in the residues from the blended tars containing the oxidized aromatic flux oil residue.
• Quinoline-insolubles are not formed in this treatment, and so are present in the treated residue in proportions of not more than about 5%.
• the selected flux oils from which the oxidized product is derived are distillate oils obtained in the distillation of tars resulting from the destructive distillation of bituminous coals. These oils boil above about 250 C. under standard conditions, and usually comprise the so-called light and heavy tar oil fractions, and may also include residues from vredistillation of lighter distillate fractions.
• Proportions of the oxidized aromatic flux oil residue as defined, up to 75 by volume based on the volume of the normal road tar/air-blown flux oil blend may be used. I have found that higher proportions of oxidized aromatic flux oil residue tend to cause crystallization of the resulting film when applied to the surface and, in the higher consistency grades (RT-7 to RT-12), prevent compliance with the ASTM float test requirement due to this crystallization tendency. Even small proportions of the oxidized aromatic flux oil residue added to normal road tars improve the temperature susceptibility and cure of the resulting blend. However, I usually prefer to use at least about 25% of oxidized aromatic flux oil residue with 75% tar, percentages between about 50% and about 75 based on the oxidized aromatic flux oil residue/normal tar blend being preferred;
• Suitable fluxing agents are those in the nature of the so-called light carbolic oil residue (LCOR) which is a coal tar fraction boiling pri- (ring and ball) and penetration with the following results, shown in Table II below.
• LCOR light carbolic oil residue
• coal tar derived fluxing agents may also be used having %3 1M 19 the same general character as the light carbolic oil residue, 0-300: (5. 2
• a Suitable filming agent is a Coal r dlstillate
• compositions of my invention preferably have dlislg z g ax fl Tfl a 100 m 5 e e'cen i e -nat' e e 40,5 tiuation residues which have p n r i indlc s as e a g tg g gf 1M fined, of above 2, preferably between about 1.0 and softening Pointaiter Heating Time (days) 0 about 0.5 and softening points of at least about C., g i 32 2 preferably between about C. and about C.
• These 2. 22.3 compositions also preferably have curing rates such that they achieve a softening point of at least about 40 C.
• the oxidized aromatic flux oil residue used in the road y .z ig i g iz z tars of Examples 1 and 2 above was prepared by air i ux O1 resloue m e i i 1 t d p d 45 blowing at 295300 C. and at air rate of 0.03 c.f.m./ with respectlve 0 s ma a gallon of charge, a selected flux oil having the following RT8, and fiuxmg the resultant blends with light carbolic properties. oil residues to RT-8 consistencies.
• the resulting blends ASTM D 246 distillation percent dist to: had the properties shown in Table 1 below as compared to 210 C 0 0 ASTM D-490 standards and the properties of the standard 50 23 5 C RT8 used. 270 C. 3.4
• the light carbolic oil residue used in the above examples had the following properties:
• Example 3 An aromatic flux oil having the characteristics set out above was blown with air in a continuous manner at temperatures ranging from 300 C.-400 C. and pressures of 5 0- 66 p.s.i.g. The resultant residue product was mixed continuously with a predetermined blend of normal road tar RT10 and light carbolic oil residue of the character employed in the foregoing examples until the consistency fell within the range of ASTM test 13-490 for RT-lO. The normal tar used and the blend obtained were tested for compliance with ASTM requirements and tor Penetration Index values as shown below.
• the standard RT-10 road tar and the oxidized aromatic flux oil residue-containing blend characterized above were applied to a test road on a fall day in Michigan.
• the standard and experimental road tars were applied from a standard tar spreader at atemperature of 225 F. and at a rate of /4 gallon per square yard.
• the tar was covered with 31B cover stone conforming to the specification Percent Passing /s" sieve 100 No. 4 sieve 35-65 N0. 10 sieve ()15
• the cover stone was applied at the rate of 30 pounds per square yard and was immediately rolled with a ten ton roller.
• Examples 4-7 Four road tars were prepared by blending mixtures of the same air-blown aromatic flux oil residue as used in Examples 1 and 2 and a standard RT9 road tar containing between 40% and 60% air-blown residue with different fiuxing oils, including (1) cresote oil, (2) creosote oil distillate to 300 C. and (3) light carbolic oil residue. These tars had the compositions shown in Table IV below.
• Two road tars were prepared by blending air-blown 170 0.0 aromatic flux oil residue with a standard road tar in the 235 2.1 poportions of appoximately 70% and by volume, 270 79.4 respectively, of air-blown residue with 30% and of 300 89.8 the standard road tar and fiuxing with a light carbolic Residue 10.0 oil residue to produce road tars containing 37.9 and 54.6 percent by volume of air-'blown residue. to form two blends as lndlcated below:
• T illustrate the superiority of the paving binders of RT 9, percent by vol 100 233 47.2 the invention in producing black bases of higher stabil- Air-blown Residue, percent by vol 54.6 7.9 ity under applied loads than normal road tars, two tars hfig f gfi' fggo gjg iag were prepared, one a Standard RT6, the other a tar of so1upiemos;, ei-e nt 'B,percent wt 89.8 83.6 35.0 m the invention containing 45% of oxidized aromatic flux i ft i g gig gf fgf g 212 L190 198 oil residue, having the constitution and properties set out wt.: below 0 to 170 C 0. 0 o. 0 0. 0
• Example 8 was applied first to a portion of Placed in the machine and Subjected to a 10ad pp approximately 1,700 f t This mix was applied at a laterally by means of a constant rate load ack until the temperature f Example 9 was then applied, at maximum load is reached. This value is a measure of a temperature f f the fi t point over a sea the maximum load the material will withstand before and length of approximately 1 f t Regular breaking takes place. Higher values indicate greater was applied, at a temperature f 0 F. to a sueceed resistance to breaking, and thus indicate greater load ing 1,700 ft length bearing capacities.
• a paving tar composition consisting solely of coal tar derived products, said composition consisting essentially of a mixture of (1) between about 25% and about 75% by volume of a standard coal tar derived road tar as defined in A.S.T.M. standard specification D490, and (2) between about 75% and about 25% by volume of a pitch-like oxidized aromatic coal tar flux oil residue obtained by contacting, with an oxygen-containing gas at temperatures between about 200 C. and about 500 C., a coal tar distillate boiling above about 250 C.
• composition according to claim 1 wherein the fluxing oil is a light carbolic oil residue.
• composition according to claim 3 wherein the standard road tar-oxidized aromatic flux oil residue mixture contains between about 50% and about 75% by volume of oxidized flux oil residue, and wherein the fiuxing oil is a light carbolic oil residue.
• composition according to claim 1 wherein the residue obtained by subjecting the said paving tar composition to distillation according to ASTM method D-ZO, has a penetration index of not less than about 1.0, and which residue is capable of setting to a ring and ball softening point of at least about 40 C. in not more than about 5 days when subjected, in a film of about .032 inch thickness to forced air circulation at 50 C.
• the process for preparing a road tar composition consisting solely of coal tar derived products, said composition meeting the specifications of ASTM D-490 and having a low degree of temperature susceptibility and a rapid curing rate, which comprises blending (1) between about 25 and about 75 by volume of a standard coal tar derived road tar with (2) between about 75% and about 25 by volume of a pitch-like oxidized aromatic flux oil residue obtained by contacting with an oxygencontaining gas at temperatures between about 200 C. and about 500 C. a coal tar distillate boiling above about 250 C.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Health & Medical Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Orthopedic Medicine & Surgery (AREA)
• Dentistry (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Road Paving Structures (AREA)
• Working-Up Tar And Pitch (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23080297

Family Applications (1)

Country Status (5)

Cited By (3)

Citations (7)

• 0
  • BE BE648117D patent/BE648117A/xx unknown
• 1963
  • 1963-05-21 US US282143A patent/US3304191A/en not_active Expired - Lifetime
• 1964
  • 1964-05-19 FR FR974982A patent/FR1395346A/fr not_active Expired
  • 1964-05-19 FR FR974981A patent/FR1405897A/fr not_active Expired
  • 1964-05-19 GB GB20644/64A patent/GB1005491A/en not_active Expired
  • 1964-05-19 NL NL6405550A patent/NL6405550A/xx unknown

Patent Citations (7)

Also Published As

Similar Documents