US2080688A - Bituminous cement - Google Patents

Description

Patented May 18, 1937 I UNITED STATES PATENT OFFICE 2,080,688 BITUMINOUS CEMENT Ulric n. Bray, Palos Verdes Estates, CaliL, as-

signor to Union Oil Company of California, Los Angeles, Calif., a corporation of California No Drawing. Application November 27, 1933,

. Serial N0. 699,931

v Claims.

The present invention relates to a bituminous cement. The invention relates particularly to wood, waterproofing concrete, building or repairing roofs, painting metal, and any of the common 1011565 to which a bituminous paint is ordinarily applied.

The value of bitumen or asphalt as a cementingand protecting agent is well known but it is desired to point out that in order to utilize asphalt l5 for a wide variety of purposes and under various conditions, it has been common practice to cut back or'to dissolve the bitumen in a volatile solvent which reduces the viscosity of the bitumen sufliciently to permit efficient application of the 20 bitumen to the problem at hand. Asphalts or bitumens which have beendissolved in a volatile solvent are generally known as cut-back" asphalts.

When the bitumen is dissolved in a volatile 25 solvent, it may be applied in a cold condition. In recent. years, bitumens have been emulsified with water sometimes after partially cutting back to permit cold application. Unless the bitumen is emulsified or, cut back, it must be applied hot, 30 that is, in a melted condition and this is often inconvenient or totally impracticable. Directing attention particularly to road building cut-back asphalt consisting of a relatively hard asphalt,

say having 50 to 200 penetration at 77 F. and 35 to 50 percent by volume of volatile solvent, is

used, for example, as a bituminous cement by admixing with the road building material, 1. e.

crushed rock,"gravel and sand, and then agitating or mixing with the road building material until 40 the bituminous cement is thoroughly incorporated. The finished asphaltic mixture is then spread on the road to secure compaction and consolidation. As the volatile solvent evaporates, the road hardens or takes a set as it is commonly 5 called. A common method in laying of low cost roads is to mix the bituminous cement and the road building materials in place upon the road by first spraying the bituminous cement on top of windrowed earth or gravel and then blade mixing 5 back and forth across the road until complete mixing has been obtained. Sometimes mere spraying of the road with oil or'cut-back asphalt is used, in which case the treatment is called penetration treatment.

The use of road oils, which are generally reduced petroleum residua, is quite similar to the use of cut-back asphalts and probably antedates the use of cut-back asphalts, particularly in the western part of the United States. Both the cut- 0 back asphalts as commonly produced and the residual road oils, may be considered as being a' mixture of a hard bituminous component and a less viscous solvent. In the case of the volatile cut-back asphalts, the diluent is a relatively low boiling distillate, whereas in the case of the residual road oils, the diluent consists of naturally occurring heavy gas oil and lubricating oil fractions. Obviously, the road oils are very markedly slower in obtaining their set and it is an open question as to whether an ordinary residual road oil ever reaches a hardened condition corresponding to the true asphalt content.

It is an object of my invention to produce bituminous cements or cut-back asphalts suitable for the above mentioned purpo'ses'having remarkable cementitiousness and rapid penetration characteristics and which may be produced at a low cost. I

It is a particular object of my invention to produce cut-back asphalts in which a low boiling solvent is formed in situ and which is distinguished from ordinary cut-back asphalts produced by blending a volatile solvent to ordinary asphalts which are hard at ordinary atmospheric conditions of temperature and pressure.

Briefly stated, my invention comprises a process for producing a bituminous cement or cutback asphalt in which a viscous stock or asphaltic residual oil having a relatively high degree of cementitiousness is cracked to reduceits viscosity and form volatile fractions therein which vola-' tilize subsequent to the application of the bituminous cement. The invention includes a bituminous cement which has been prepared by cracking a viscous asphaltic stock or an asphalt such as a steam refined asphalt to produce fractions in the bituminous cement which will reduce its viscosity and which will evaporate from the bituminous cement upon its application to a road or other places and thus permitting the remainder of the cement toset up or harden. V

More specifically stated, my invention resides in a process for producing bituminous cements which are particularly adapted to'penetrate into the aggregate of a road or to be mixed therewith and then set up as a hard bituminous cement which comprises subjecting an asphaltic residual oil or topped crude todistillation to produce an,

fractions which will volatilize when applied to the road or other places of use and thus permit the remaining material to set up as a minous cement.

hard bitllvacuum until a heavy road oil or asphaltre mains as; a distillation bottom which is substantially free from fractions boiling below 700 to 750 1'.- and approximately 80 to 85% of 80 penetration asphalt. I then. subject this asphaltic material, to high temperatures for a sufiicient time to produce by cracking low boiling products which will serve as diluents for" the asphaltic component and thus giving a product having viscosity and distillation characteristics'analogous to cut-back asphalts produced by adding a volatile diluent to ordinary asphalt. The bituminous cement will contain from 70 to 80% of 80 penetration asphalt and the remainder comprising cracked diluents and oils. Inother words, I. employ'a heavy bituminous material which has a fairly hlahcementi s 1 but which is so viscous that it cannot be used in an unaltered state restricted conditions where heat can be employed. I then subject this asphaltic material to cracking conditions for the purpose of reducing its viscosity and giving a product still having a high asphalt content and which hardens upon exposure in thinfilmstotheatmospheredue'totheevap oration of the volatile cracked solvent.

The conditions to be maintained during cracking of the heavy road oil should be-well known to those skilled in the art of cracking. The cracking may be'carried out in any of the conventional cracking units such as the Cross and Dubbs cracking units. Generally, I prefer to subject the stock to such cracking conditions as will produce up to approximately 40% of volatile oils boiling belowm I". which are retained in the bituminous contentof the stock after cooling the cracked product. The crack- -ing conditions will vary but generally pressures of 400 to 1000 lbs. per square inch and high temperatures of 800 to 900 1''. will sufiiee to give the proper degree of cracking and viscosity reducdistill of! some of the light fractions so as to leave a residuehaving an initial; distillation point of approximately 350 to 450' I". in the liquid. Such a material will correspond to an asphalt which has been cut back with kerosene or heavy gasoline.

In order to retain the volatile cutting solvents in the cracked product or residue, the distillation of the cracked product is carried out under pressure so that only the most volatile fractions are removed by distillation. The object in removing the verylight fractions, that is, frac-' tions'boiling up to 250 1'. by the distillation is toraise thefiash pointsoastoredueethe danger from inflammability during shipping and handling of the bituminous cement. Also. it is desirable in a bituminous cement having a definite viscosity and which is to be used for the purposes described herein that low boiling fractionsandfixedgasesaressparatedfromtbe heatea fractions 'be absent for the reason that evaporate too'quickly after application cement causing an increase in'viscesity before the cement has had time to penetrate and coat the particles of the road building materials The following 18 ll specific example cf'a method for carrying out my invention to produce cutbackasphalt. Howevenitistobe that this-example is merely illustrative of one embodiment of'the invention and is not to be construed as limiting my invention:'

crude oil and having'a gravity of 10.4 A. P. 1., a flash point of 480' E, a Saybolt furol viscosity of 3000 seconds at 122' P. and 102 seconds at 210' F.- and containing about 82% of 00 penetration asphalt and substantially free from fractions remaining residue. The by change and the operation in fiash drum is preferably controlled so as to oil the very light constituents of the cracked mixture and toretaini'ractionsintheresiduehavingaproper initial points such as, :6: example, the

l001". Thismaterialwa'sthenplacedinstor'age.

Forthesakeofillustratingthepeculiarcharacteristic of the bituminous cement as produced A tely to tbinthe'mveofmyeven wer bytheprocessformingthesubjectmatterofmy' invention, the following tabulation is submitted which has been taken from inspection data on samples of the materials indicated in the table. The first column of figures reprants the characteristics of the heavy road oil stock which was cracked, as described above, to reduce its viscosity and thus produce the bituminous cement of the secondcolumnoifigures. 'lhethirdcolumnof figures represents a road oil having substantially the same .content of 00 penetrationasphalt as the bituminous cement produced by my invention,

whereas the fourth column represents a road oil having approximately the same flaybolt furol viscosity at 122 1''. as that ci'tbe bituminous cement. Hie last column of figures repi'ments the characteristics of an "3 grade asphalt which has been cut back with approximately 20% to 27$ kerosene. This kerosene cut-back asphalt abo contains approximately the same percentage of 00 penetration of asphalt as thecracked bituminous cement produced by myprocess. It will be observed that an "B" grade asphalt is a steam re-' fined asphalt produced by steamdistilling or topping an asphaltic crude oil residuum to vaporlse the lighter fractions contained therein and to leaveasphalt having a penetration at 77 1'. of approximately l00 to 300, a point of 85 to 110 1''. and a ductility at 77. l". of cm. v

3 boiling below 680 n will evaporate from the bitu- Tml I Comparison of characteflsticsofbituminous cement made by cracking a heavy road oil stock with the characteristics of conventional road oils and cut-back asphalt Bitumi- Hesvy nous o8- 2 53: Test 3 ment by r road cutstfock ammo M on SW No. 1 No. 2 asphalt Gravity, A. P. L- 10. 4 12.0 11.1 13.8 is. 2 Flash point, F.--..- 480 200 330 300 176 Percent of 80 pene-' tration asphalt... 82. 0 74. 9 73. 7 58. 0 74. 0 Time to reach 80 pignegnlaltion as- 1 a 9 M is ours 5 2 3 Vl cosity, Saybolt iurol at 122 F.---. 3,000 141 1,230 166 163 Viscosity, Sayboit iurol at 210 F- 102 16 2) 2o Distillation Initial, F 650 422 622 555 435 Percent distilled at F 0.0 0.3 0.0 0.0 0.2 Percent distilled at 0.0 7.0 0.0 0.0 20. 5 Percent distilled at Test on Residue from Distillation Penetration at 77 F 300+ 300 300+ 300+ 194 Saybolt iurol VlS- .cosity at 210 10s or 51 so 270 Solub l ty in CS... 99. s 90.8 so. 8 00. s so. a Solubility in Cpl-.. 99. 8 W. 3 99. 8 99. 8 ,99. 8

It will be observed mm the above table that the bituminous cement or cut-back asphalt produced as above stated, will have a considerably lower Saybold iurol viscosity at 122 F. and at 210 F. than Road Oil No. 1 of the table havin produced by my process, it wlllnecessitate the use of a road oil having a smaller percentage of 80 penetration asphalt than the bituminous cement. Thus, Road 01] No. 2 having Saybolt iurol viscosities at 122 F. and 210 F. of 156 and20, re-

spectively, which are slightly higher in. viscosity than my bituminous cement will contain only 58% of 80 penetration asphalt as compared to substantially of penetration asphalt in my bituminous cement.

Consequently, the cementitiousness obtained from road oils is not as efl'ecti've asthebitumlnous cement producedby my process. The time required to reach 80 penetration asphalt is considerably greater for the two road oils mentioned which are respectively 6 and 9 hours as compared to 2 hours for the bituminous cement. By inspection of the distillation data, it will be observed that the bituminous cement contains a considerablyhigher-percentage of fractions distilling at I 7 437 F., 600 F. and 680 1''. than the aforementioned road oils which, of course. makes my ceminous cement" or cut-back asphalt when applied on the road, or other places, in thin films or layers in approximately two months so that a distillation test at 680 F. is indicative of'the amount of materials which are normally expected to evapotime to reach 80 penetration asphalt; it has a lower Saybolt iurol viscosity at both 122 F. and 210 F. for even a higher asphalt content and it has a less total loss on the distillation test at 680 F. which indicates a higher percentage of asphalt remaining on'the road per gallon of the cut-back asphalt applied. Also, it will be observed that the A. 1?. I. gravity of my bituminous cement is considerably lower than the kerosene cut-back asphalt for even a lower Saybolt furol viscosity. The bituminous cements produced by my process exhibit lower A. P. I. gravities tor thesame viscosities than ordinary cut-back asphalts which have been produced by dissolving an asphalt with a diluent such as kerosene. 7

One of the important advantages and characterlstics of my bituminous cement over a kerosene cut-back asphaltwhich cannot'be detected by an inspection of the laboratory distillation test is that my bituminous cement hardens better than the kerosene cut back asphalt. This is probably due to the aromatic nature of the cracked diluent in the cement which has a higher evaporation tendency than is shown in the laboratory distillationtest.

By controlling the penetration or viscosity of the asphaltic material before it is cracked, the extent to which the asphaltic material is cracked and the extent to which the cracked products are topped, a bituminous cement of almost any desired voltality and viscosity can be obtained. To

illustrate the flexibility of my process to meet different requirements for rate of evaporation and development 01 cementitiousne'ss, the examples in Table II are submitted which correspond to cracking a 175 penetration E grade asphalt under diiferent lengths oi'time at a temperature of 800 F.

- Tam II Tests of cracking 175 penetration "E" or asphalt Run 1 Run No. 1 No. 2

Production conditions Crackin time, minutes at 800 F 3. 4 Mn Peroent 260 F. E. B. P. gasoline distilled 0.0 7.3

Tall on product after removing 350? F. E. B. P.

r gasoline Gravity, A. P. 10. 5 7. 0 Viscosity Saybolt iurol at 12 F 07 I 4! Flash point, r m Firepoint, F Percent of a0 penetration asphalt 72. 4 71. 7 Time to reach 80 penetration asphalt, hrs... 1M 1 Distillation Percent mum n' 431 F a s. 5 Percent distilled at 000' F 2l. 6 no Percent distilled at 000 F... 27.5 no

Test on residue from distillation Y I v Penetration a 17 F m 42 Solubility in CS1. $.40 04.79,

, ploy as crackinfstock, the

'cementitiousness upon evaporation asindicated by the distillation residue penetrations of 115 and 42 at 77 '1". for the respective runs and that the cement has rapid curing properties as shown by .the large amounts of distiliateobtained inthe usuai distillatiomtests.

The process for producing the bituminous cement as described above is not to be restricted to the particular types of raw materials as given above, 1. e. heavy road oil or asphalt. As cracking stocks. I may employ certain steam refined aspha'lts having melting points varying from 65 to 250 F. and also air-blown asphalts. The use of air-blown asphalts'is' advantageous when it is desired to produce a'bituminous cement which will exhibit a minimum temperature susceptibility, 'i.- e. minimum ,change in viscosity for change in'temperature, upon evaporation of the diluent. Bituminous cements produced from air-blown i'asphalts by "'the methods described showlless !bieeding-in hot weather and less brittleness in cold weather. I mayalso emfrom asphaltic oils by means of such normally gaseous hydrocarbon solvents as. liquid propane. runmay'be cracked to give a relatively low viscosity-cement of high adhesiveness and cement value. of bitumens and wax can be cracked to give products which contain less wax than w original In this regard, at

to precipitate the wax from solution. to give a I cracked product containing volatile fractions capable of as a diluent and then blending this cracked product or fraction thereof with the propane precipitated bitumen orasphalt- In this manner. a volatile bituminous cement would be obtained from wax and bitumen without w ccssity of cracking the bitumen;

Whilesome of the'commonuses to-which my cut-back or bituminous cement may be put comprise road. building, preserving wood, painting mctaL-repeiring roofs. etc., as stated hereinabove, I have found that'the cut-back asphalt producedby my process is specially adapted --asanadhesiveorbindingagentforthetopsurface of the moimds of tailings-dump of copper or other mines to prevent erosion of the mound by the wind and rain. When'these-mounds dry tilt, a dry surface of dust remains which is carred by the wind over the surrounding communities, thus creating a nuisance. By spraying the surface of the ftaiiings dump with the cut-back asphalt inamounts of approximately 1.5 galions per square yard of surface, the asphalt will penetrate rapidly through the m Wte to such depth as to form an oiled shell of approximateiy one to one and one-half'inches in thickness when the volatile cracked material has evaporated, thus leaving a satisfactory protection against the elements. The high asphalt content of the cut-back asphalt and good volatility resulting in development of remarkable cementitiousness and peculiar effectiveness in rapidly penetrating the tailings render the cutback asphalt particularly suitable for this type of work.

It will be observed that for determining the melt p n penetration. ductility and flash accuses point of the ssphalts mentioned herein, the following methods outlined by the American Society of Testing wereused Melting point D4646 Penetration 13-5-25 Ductility 13-11346'1 Flash point, Cleveland openv cup me 20-02-34 Percent of penetration asphalt--- D-243-26T It is to be understood that the above description is merely illustrative of preferred embodiments of my invention of which many variations may be made within the scope of. the following ing from the spirit thereof.

Iolaim:

1. A cracked bituminous cement which is adapted for use as a ,road building. dust laying, wood preserving material or the like, said bituminous cement containing approximately 70 to 80% of 80 penetration at 77 1''. of cracked asphalt and approximately 20 to 30% of cracked oil fractions. said cracked oilfractions in said bituminous cement being substantially free from fractionsbbiling'belowiOO I". and the major proportion of said cracked oil' fractions boiling below 680 F.

2. A cracked bituminous cement which is adaptedfor use as a road buildinmdust laying,

claims by those skilled in the an without depart- T woodpreservingmaterialorthelikewhichis.

produced by cracking an asphaltic crude oil residuum. said'bitumihous cement containing approximately 70 inc-80% of 80 penetration at 77 1". of cracked alphait andapproxlm'ately .20 "to 30% of cracked oil fractions, said cracked oil fractions in -Zsaid *bituminous cement being substantially free fromfractions boiling below 400' l". but contions -'bel owf680 1".

-3. a--cracked bituminous cement which is tainingapproximatcly 15%"01' cracked oil frac adapted foruseasaroadbuiiding,dustlaying. wood preserving material or thelike which is stantiaily-free from fractions boiling below approximately 400 F.- but containing approximately 15% of cracked oil iractions boiling below 600 I". and a substantial amount of cracked oil fra'c- 30% of cracked oil'fractions. said cracked oil fractions in said bituminous cement being sub-' stantialiy free from fractions boiling beiow'approximately 400 1''. but containing approximately 15% of cracked oil fractions boiling below 680 1 and approximately 7% of cracked oil fractions boiling below approximately 600 1".

a. a cracked bituminous cement which is.

adapted for use as a road building, dust laying, wood preserving material or the like which is produced by cracking an asphaltic .crude oil residuum, said bituminous cement containing approximately 70-to 80% of 80 penetration at 77 I. of cracked alphalt and approximately 20 to 1| 30% of cracked oil fractions, said. cracked oil fractions in said bituminous cement being substantially free from fractions boiling below approximately 400 F. but containing approximately 15% of cracked oil fractions boiling below 680 F. and approximately 7% of cracked oil fractions boiling below anproximately 600 F. and said I cracked bituminous cement having a Saybolt furol viscosity at 122 F. and 210 F. of 141 and