JPS5942703B2 - Method for producing coated particle aggregate composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fluid composition of molten sulfur and asphalt,
Compositions of particle aggregates coated with fluidized sulfur and asphalt compositions, methods and apparatus for the production of these fluidized sulfur asphalt compositions and particle aggregate compositions.

More particularly, the invention provides a system for producing aggregates coated with specific mixtures of molten sulfur and asphalt suitable for spreading and compacting, for example to form roads or to renew road surfaces. Regarding. Coating aggregate materials such as sand, gravel, crushed stone, or mixtures thereof with hot fluid asphalt and applying the coated material as a uniform layer onto the subgrade or previously constructed road while still hot. It is well known to compact the uniform layer by rolling with heavy rollers to form a smooth surface road or roadbed.

Thousands of miles of roads in North America and elsewhere have been built or maintained by the common force law, and millions of dollars have been invested in equipment to implement the force law. For the force method, an adequate and economical supply of pavement grade asphalt mixed at a ratio of about 5 to about 12% by weight of the coating mass has been essential. However, due to the growing global shortage of petroleum products and the ever-increasing demand for the use of heavy petroleum distillates as fuel, it is necessary to extend the amount of paving asphalt that can be obtained from available petroleum. ) It has become a good idea to find a way to do this. It has long been known that sulfur can be mixed with asphalt in a wide range of proportions for various purposes.

However, there are many different difficulties in utilizing such mixtures in road construction, and despite the recent clear need for sulfur/asphalt bond aggregates by the road construction and road paving industries. No suitable system has hitherto been devised to meet this need. For example, Charles
sT. Canadian Patent No. 755,999 issued April 4, 1967 to Metcalf states that the voids between the aggregate particles are completely filled with a sulfur/asphalt mixture containing at least 50% (and up to 800 I) sulfur; Paving compositions of particle aggregates are described in which the particles are present in the mixture as discrete, separate phases that act as fillers between the aggregate particles. Other documents mentioned in the patent specification describe various other sulfur/anuphart paving compositions, but none of these have been accepted in the road construction and paving industry. These prior art compositions include sulfur/asphalt reaction products, in which the sulfur is preplasticized with one or more complex compounds prior to mixing with the asphalt (Prepla
cticized) sulfur/asphalt mixtures, and compositions in which the proportion of sulfur is so small as to have no significant effect on augmenting or replacing asphalt in the composition.

Now, virtually 25 to 40 parts of asphalt
~ If a sulfur/asphalt mixture having substantially 60 parts of sulfur is properly mixed with each other and then with a suitably sized particle mass, it can be applied to roads, e.g. using conventional asphalt road paving equipment. It has been found that a paving composition is obtained which can be applied to form a subgrade or surface layer for paved areas such as airport runways and parking lots.

Ratios and percentages referred to herein are weight ratios and weight percentages unless otherwise specified. The present invention thus provides a flowable composition of molten sulfur and asphalt suitable for coating a solid mass and forming a binder therefor.
a fluid asphalt phase having a temperature in the range C) and containing sulfur in a proportion of from substantially 25 to substantially 60% by weight of the composition, a portion of the sulfur being present within the asphalt phase; and the rest (Balanc
e) relates to a composition dispersed therein as sulfur droplets with a diameter ranging from 1 to 50 microns.

The present invention further comprises in a paving composition a particle aggregate of size-controlled particles suitable for the base layer or surface layer of a paved area, preferably 250-310°F (121-154C), preferably 270°C. ~2953F' (132~146℃
) and the particles are coated at a temperature not higher than 3107F' (154C) with a binder containing 75 to 40 parts of fluidized anuphart to 25 to 60 parts of sulfur; A portion of the sulfur is homogeneously bound within the asphalt and the remainder is emulsified therein as sulfur droplets ranging in size from 1 to 50 microns in diameter, preferably from 1 to 10 microns. The present invention relates to a composition characterized by: Furthermore, the present invention provides a method for producing a coated particle aggregate composition, in which (a) 250 to 350 particles F' (121
~177 has 275~300')F'(135~149
A metered stream of fluid asphalt having a temperature in the range and molten sulfur having a temperature in the range 250-310'11F (121-154°C) preferably 270-295'F' (132-146°C) to form a combined stream having a temperature in the range of 250 to 310 CF (121 to 154 C), preferably 270 to 295 FF' (132 to 146 °C), and a metered stream of The streams are blended at a ratio of 25 to 60 parts of sulfur to 75 to 40 parts of asphalt, and the blended streams are mixed to sufficiently disperse the sulfur in the asphalt, so that the asphalt contains 1 of the sulfur.
homogeneously dissolved and otherwise combined and the remainder of the sulfur is emulsified in the asphalt as a separate phase of droplets in the size range of 1 to 50 microns, preferably 1 to 10 microns. ) The resulting binder blend stream is passed through 310′)F′(
(d) the resulting mixture is agitated to homogeneously coat the assemblage with the blended stream, and optionally (e) the coated aggregation. The process is characterized in that the coated mass is discharged and transported to the point of application before the body has been cooled below a temperature at which it cannot be compressed.

The present invention further provides an apparatus for producing a coated particle aggregate pavement composition including (a) pumping means for delivering a continuous metered flow of molten sulfur; (b) a continuous metered flow of fluid asphalt. (c) 25 to 40 parts of asphalt to 25 to 40 parts of sulfur;
The streams are continuously blended in a ratio of 60 parts and mixed thoroughly to emulsify liquid sulfur that does not homogeneously combine with the anuphart in the blended stream as droplets in the 1-50 micron size range. (d) blending means for making the flow of the melt sulfur flow 250 to 310 F (121 to 154 melt C);
The flow of the fluid asphalt is in the range of 250 to 350
CF (121 to 177 degrees C) and temperature control means for maintaining the blended stream in the range of 250 to 3100F' (121 to 15'C); (e) the metered blended stream; a metered amount of particle aggregate having a temperature not higher than 3100F'(15'C), mixing means for homogeneously coating said particles with a blended stream; The present invention relates to an apparatus characterized in that it includes discharge and conveying means for transferring the coated assembly to the point of application before it has been cooled to a temperature where it cannot be compressed.

Furthermore, the present invention provides an apparatus for producing a fluidized sulfur asphalt composition, including (a) pumping means for supplying a metered continuous flow of molten sulfur, and (b) supplying a metered continuous flow of fluidized asphalt. (c) 25 to 40 parts of sulfur to 75 to 40 parts of Anufalt;
The streams are continuously blended in a ratio of 60 parts and mixed thoroughly to emulsify liquid sulfur that does not homogeneously combine with the anuphart in the blended stream as droplets in the 1-50 micron size range. (d) the flow of the molten sulfur to a temperature of 250 to 310'1 F (121 to 154 molten C);
), the flow of the fluid asphalt is between 250 and 35
0 F' (121-177 C) and temperature regulating means for maintaining the blended stream in the range 250-3100 F' (121-154 C). .

The ratio of sulfur to anufphalt in the compositions of the present invention is very important; sulfur increases the amount of asphalt in the composition and thus reduces the proportion of asphalt conventionally required in connection with aggregates. Not only does sulfur affect the physical properties of the asphalt with which it is mixed in the present invention (for this reason it is economically desirable to use sulfur in as high a proportion as possible), but it also affects the physical properties of the asphalt with which it is mixed. The ratio becomes critical in relation to the critical limiting condition of .

Thus, sulfur ratios that are substantially significantly lower than 25% by weight of the binder are inappropriate because at such ratios, sulfur in the form of droplets in the binder is This is because it is insufficient to achieve the advantages of Similarly, sulfur ratios substantially higher than 60% by weight of the binder are inappropriate because amounts of sulfur in excess of that ratio will coalesce rather than remain dispersed as fine sulfur droplets. higher ratios even cause a phase transformation such that the dispersion becomes an asphalt-in-sulfur dispersion rather than a sulfur-in-asphalt dispersion, thus completely destroying the expected bonding properties of the binder. It is from. Suitable ratios of sulfur and asphalt are based on the relative market prices of the components and the optimal desired physical properties of the paving or other composition with which they are to be combined, from 65 to 50 parts of asphalt. 35 to 50 parts of sulfur. Typical physical properties of a typical 85-100 Pen paving asphalt formulation and specific proportions of molten sulfur for use in accordance with the present invention are provided in the following table by way of example. The relevant temperatures for the present invention vary inter alia with the temperature at which the sulfur and asphalt are in contact;
It should be recognized that many reactions can occur between sulfur and asphalt. Practically 3000F' (149
℃), the chemical reaction of sulfur and anuphart that releases hydrogen sulfide does not occur to a violent extent. Thus, in order to avoid the risk of hydrogen sulfide generation in the present invention, and when using the present invention for road pavement, the temperature of the sulfur and asphalt mixture should be kept at substantially 310°F (154°C). It is essential to limit the temperature of the mass to be coated with the sulfur/asphalt binder mixture to a range substantially below 310°F (154°C). These temperature limitations are related not only to the avoidance of hydrogen sulfide generation, but also to fuel savings and the practicality of compacting the coating assembly after it has been spread on a road or other foundation. In conventional asphalt aggregate plants, the aggregate to be coated with asphalt is typically heated to about 3500F (177°C).
The material is heated to a temperature high enough to keep the asphalt covering it soft until it is applied onto a road or other foundation and compacted. In the present invention, for the reasons set forth above, the assemblies should not be used at temperatures higher than about 310 F' (154 °C), and the temperature required to heat the large quantities of assemblies used in this manner is not sufficient. This makes it possible to significantly save fuel. Furthermore, even though the coating mass is applied and compacted at temperatures significantly lower, e.g., 20 to 500 F (11 to 28 C) lower than the temperatures used when applying and compacting conventional asphalt coating masses, The sulfur/asphalt coated assemblies of the present invention are readily and successfully utilized in conventional construction using conventional asphalt road construction equipment. The reason is that the sulfur/anuphart binder remains a fluid at such low temperatures, and thus aggregates coated with this binder can be used at these temperatures without the need to modify road construction equipment. This is because it can be applied and compressed. The molten sulfur/asphalt binder used in the present invention is an important component whose manufacture and application onto the aggregate is completed within the shortest possible time, starting from the initial formulation of the molten sulfur and/or asphalt components. The elapsed time before application of the mixture onto the mass is substantially a maximum of 1 hour, preferably less than 15 minutes, even more preferably less than 5 minutes and most preferably 1 hour.
It is possible to make the time shorter than a minute.

Thus, according to the most preferred embodiment of the invention, molten sulfur and fluid asphalt are combined for a few seconds and mixed vigorously at the ratios and temperature ranges mentioned above to achieve (a) the amount of asphalt and sulfur within the temperature ranges; (b) allowing the remaining molten sulfur to be dispersed as sulfur droplets with sizes ranging from 1 to 50 microns; the resulting mixture
In the following seconds, the substantially 310 becomes F'(1
The coating is applied onto the mass at a temperature not higher than a maximum temperature of 54° C.). The resulting coating mass can then be applied by spreading and compacting at the point of use within the time required for the coating mass to cool to a minimum compression temperature.
When blended together in the molten state and in the proportions mentioned above, the sulfur and asphalt are mixed vigorously so that the sulfur is rapidly finely and homogeneously dispersed within the asphalt, thus increasing the amount of sulfur. The mixing allows liquid sulfur to dissolve and react within the asphalt and homogeneously and intimately emulsify the rest of the sulfur within the asphalt matrix; It is also important that it be vigorous enough to ensure fragmentation into droplets of average size. It will be appreciated that when carrying out the force method of the present invention, the force method of the present invention is most conveniently carried out entirely in a continuous force method with a continuous flow of components throughout the various stages. There will be.

However, it is possible to utilize some batch operations, thus requiring some intermittent or semi-continuous operations to accumulate components at other stages and/or between stages to form batches. is possible and often expedient or necessary. Thus, in the final stage of the force process, the coated aggregate is customarily delivered to its point of application, which may be several miles from the point of manufacture, from the accumulated batches discharged from the continuously operated aggregate coating stage. The cargo is transported as one truckload of cargo, each containing a. Similarly, the coating step can be carried out, for example by Batchpu
It may be a batch mixing operation utilizing a batch pugmill (gmill), into which a batch of aggregate is metered from a supply of storage aggregates, and a metered amount of sulfur/asphalt binder is continuously added to the batch pugmill. It is added as all or part of the continuous stream discharged from the sulfur/asphalt mixing stage, or as an intermittent stream discharged from the sulfur/asphalt mixing stage. Because of the relatively viscous nature of the ingredients and the vigorous agitation required to emulsify the sulfur droplets within the asphalt, sulfur and asphalt are added simultaneously and continuously to the mixing operation, and the resulting sulfur asphalt is removed from the mixing operation. such that they are drawn simultaneously and sequentially so that the accumulation of components during the mixing step is minimized, thus minimizing the amount of back-mixing that can occur and facilitating the formation of a homogeneous binder. It is highly desirable to incorporate and/or mix sulfur and asphalt during construction. In the device according to the invention, the pumping means according to the invention for pumping molten sulfur are also suitable pumping means suitable for pumping fluid asphalt, which are well known in the art.

Temperature control means for maintaining the sulfur and asphalt streams within the desired temperature range may be, for example, thermostatically controlled electrical heating elements or water vapor tracing.
g) It is advantageous to have hot oil or tracing line circulation to compensate for heat losses during material transfer from component storage to the mixing stage. The dispensing and mixing means may be conventional industrial homogenizers, blenders, colloid mills, or operating at elevated temperatures that can create high shear forces in the fluid asphalt and required to disperse the molten sulfur in the fluid asphalt. may include other mixers that may be used. It is of course preferred that the continuous streams of molten sulfur and asphalt be rapidly combined and mixed during simultaneous flow through a small mixing zone, without recycling or back-mixing of the resulting sulfur/asphalt binder. It is a kind of thing. The mixing means for mixing the metered amount of the binder and the metered amount of the aggregate to coat the binder on the aggregate may be, for example, a batch pug mill or a continuous pug mill, or a simultaneous continuous This may be a recently developed continuously rotating dryer drum type mixer for drying and coating the aggregate with an asphalt binder to form a paving mix. The mixing means may be located in close proximity to the sulfur/asphalt mixing means so that the sulfur/asphalt binder can be coated onto the mass immediately after its formation, preferably immediately after. suitable. Marshall Mix design of a paving mix with a 50:50 sulfur:asphalt binder and a mix containing only asphalt as a binder (85-100pe0 grade).
Through laboratory comparison of the properties of
It has been shown that sulfur/asphalt binders provide mixtures with much higher stability.

100% 85-100pen Asphalt Binder (AC
) and 50:50 sulfur/asphalt (85-100
Typical commercial data for samples made with pen) binder (SA) are as shown in the AC and SA columns of each of the following tables.

The higher binder content required for optimum porosity of the sulfur/anuphart binder is as a result of the higher specific gravity of the binder containing elemental sulfur, which has a specific gravity of about 1.96. be. Additional marshall data collected in laboratory tests, tests, and one practical test confirmed the following observations regarding paving mixtures made in accordance with the present invention. (1) The mechanical stability of the test samples is significantly higher than samples made using only asphalt as a binder.

(2) The marshal stability of the test sample increases as the sulfur content increases within the specified range of the present invention.

(3) Despite the high marshal stability of the sulfur/asphalt binder-containing test samples, the test temperature of 1400 F (60
No significant loss of flow properties occurred at temperatures (°C) and the flow properties shown in the table above are generally within acceptable ranges.

(4) It can effectively stabilize low quality aggregates such as BlOwsands and low grade aggregates.

(5) The marshal stability of the test sample after immersion in water is
The stability is the same as that of the unsoaked sample, indicating that the sulfur/anuphart binder imparts high water resistance.

(6) Various penetration grades of paving asphalt can be used to produce a good sulfur/asphalt binder.

In addition to the aforementioned marshall data, additional evaluations of the sulfur/anuphart binder-containing paving mixtures according to the invention have shown, for example, the low temperature response (RespOns) of the mixtures.
e) is not significantly (i.e. within test error) different from that of a conventional paving mixture containing only an asphalt binder, such that the sulfur/asphalt binder does not adversely affect the low temperature response of the mixture. It has been shown.

Similarly, fatigue resistance evaluations showed no adverse effects from using a sulfur/anupharth binder in the paving composition in place of an asphalt-only binder. Low temperature properties and fatigue resistance are determined using force methods established in the industry, such as Haas, R. C. G. , ゞJ)Esign
ingAsphaltPavewentstOMini
mizeLOwTemperatureShrinka
geCraCking″1AsphaltInstit
uteRep0rtRR73-1, January 1973, and MOrris and Haas, Character
rizatiOn0fBitumin0usMixtu
resf0rPermanentDef0rmati0
nPredicti0ns″1ASTMSTPPub1
It was evaluated by the force method described in 1cat10nN0, 561, 1974. Furthermore, compared to 100% asphalt coatings on the aggregates tested, sulfur/asphalt (50:50) coatings on similar aggregates were less resistant to peeling the coating from the aggregates after prolonged immersion in water. It showed excellent resistance. The following examples illustrate various aspects and advantages of the invention.

Example 1 In this example, the manufacture of an Anufalt road paving composition using one portable mixing device together with another permanently installed mixing device and use by heavy duty tractors of a square stone and stone crushing plant. Application of the composition as a surface coating to a previously created foundation at a quarry entrance is described.

The portable device is a mobile storage volume for molten sulfur and asphalt (MObilestOrageCapa
Clty), pumping means for supplying a metered continuous stream of molten sulfur and asphalt from said reservoir, temperature control means for regulating these streams to the appropriate temperature range desired, and formulation and including mixing means; all of these connecting supply and discharge lines are insulated and equipped with electrical resistance heating elements for heat supply and temperature control means for the equipment and materials through which the materials are conveyed. . The permanently installed mixing equipment comprises part of a long-established conventional asphalt aggregate mixing plant and batch weighing means for weighing batches of crushed stone and sand, weighing batches of anufult. Separate weighing means for 3000 lbs (1360 kg) of aggregate and asphalt during a controlled mixing period
) had a batch pug mill with a conventional counter-rotating twin-shaft unit capable of mixing batches. The mixed batch of asphalt mass could be discharged by gravity directly from the mill to a transport truck. sulfur and asphalt pump delivery means for carrying out the production of the paving composition;
The blending and mixing means and connecting lines were heated by electrical resistance heating elements until the apparatus was heated to substantially 300↑ (149 degrees Celsius). The movable sulfur and asphalt storage tanks are then connected to a separate pair of ROtO-King7 positive displacement pumps ( Model LQ32). Each of the positive displacement pumps is
3 horsepower (2
．． 25K. W. ), had a mechanical variable speed drive driven by a three-phase electric motor, and each was capable of delivering 3 to 43 US gallons per minute. The molten sulfur and asphalt are pumped by these pumps at the desired ratio through separate short insulated lines to a Y-junction where the molten sulfur and asphalt streams are combined and the short Paddle diameter 3 inches (8cm)
G of nominal size 5 inches (13 cTn) through the connection of
ifOrd-WOOd was flowed into the inlet of a pipeline mixer (model PL5). Operates at 3500 rpm and includes a single high speed turbine stator with eight 1+ inch diameter (31 mTn) holes in the stator and a stator to rotor gap of 0.008 to 0.012
The mixer was directly connected to a 20 horsepower (15 K.W.) motor with a diameter of 1.5 inches (0.203-0.305 mm).

As it flows through the mixer, more than about 20% by weight of the sulfur and asphalt formulation does not react with or dissolve the sulfur in the asphalt, and the sulfur particles are less than 10 microns in diameter, with an average diameter of 1 to 10 microns. Emulsified or dispersed in the asphalt as smaller sulfur droplets, the sulfur in proportions up to about 20% by weight of the formulation reacted with or dissolved in the asphalt. The sulfur/asphalt mixture is conveyed from the mixer through an insulated flexible conduit to a metering pan where the desired quantity metered by weight is accumulated and then discharged onto a mass of metered quantities in a pug mill. It was done. The aggregates fed to the pugmill were approximately 35
% of + inch (10 mm) crushed rock, i.e. all the crushed pieces are smaller than a inch (12 mm) and more than 90% have an opening of 0.187 inch (4.76 mm). S. Sievese
crushed stone, such as remains on the ries screen), 49
% crushed stone decoration, i.e. 98% is 0.187 inch (4
．． 76 mm) screen openings and 90% remains on the 200 mesh screen with 0.0029 inch (0.074 mm) openings, and 1
6% sand [99% 0.0469 inch (1.19 m0
0.0029 inch (0.0029 inch).
The sand remained on a 200 mesh screen with openings of 0.074 mm). The agglomerate components are dried by passing through a heavy oil-fired rotary dryer, and the heated material is discharged from the rotary dryer into a storage container on the pug mill where it is weighed in batches of desired proportions. Fed to pugmills. 290~300F
The mass having a temperature in the range of 143-149'F (143-146 mass C) and the sulfur/asphalt mixture having a temperature in the range of 290-2951'F (143-146 mass C) are metered into the mill in the desired ratio and After being mixed therein for a controlled period of time to coat the sulfur/anuphart binder over the aggregate, it was loaded onto trucks from the mill and transported to a conventional asphalt paving machine in a nearby paving section. .

The coated mass is now applied to a depth of 2 inches (5c7rL) over a previously paved foundation and rolled using tandem rollers in a conventional method for laying and rolling Anufalt pavements. It was rolled using.
There were no difficulties in laying and rolling to compact the surface. The asphalt used in the example was 85-100 pen paving asphalt.
5 Typical properties of this grade of pavement asphalt are as follows. V
V9V'V Sulfur was technical grade elemental sulfur, a by-product of petroleum refining.

In the paving composition of this example, sulfur and asphalt were blended in a 50:50 ratio. Conventional mechanical mix design testing using the aggregate and the 85-100 pen asphalt as the sole binder revealed that the bond with the aggregate is suitable for optimal paving composition properties. The optimal ratio of agents was determined in the laboratory to be 5.8%. Since sulfur has a significantly higher specific gravity than asphalt, and therefore the sulfur/asphalt blend also has a higher specific gravity than asphalt, it is natural to completely coat equal weight assemblies with equal coating thickness. Since substantially equal volumes of binder are required for this purpose, the weight ratio of the optimal sulfur/asphalt mixture as a binder for paving compositions is higher than when only anuphalt is used as the binder. The optimum weight ratio of 50:50 sulfur/asphalt binder for said aggregate is thus in the range 7.0-8.0 (:f) as determined by Marshall test. , a ratio of 7.7% was used in the paving composition of the example. To demonstrate that the sulfur/anuphart binder contains only dispersed droplets of liquid sulfur smaller than 10 microns in size, samples of the binder being added to the mass were randomly taken and placed under the microscope. Visually inspected.
Of particular interest in the marshal test results is that the stability measurements on the test samples showed that the optimal sulfur/asphalt aggregate ratio resulted in a marginal stability of slightly lower than 2000; According to the ratio, it was shown that a marshal stability higher than 3000 was obtained and the increase rate was greater than 50%. Furthermore, the marshal stability is greater,
Despite the fact that the strength of the finished surface coating after rolling and curing of the paving composition is shown to be greater, due to the presence of finely dispersed sulfur droplets in the binder, the paving composition It is not more difficult to compact while things are still hot; and also, hot paving compositions containing sulfur/asphalt binders can be rolled and compacted before they become difficult to effectively roll and compact. It was possible to cool to much lower temperatures than with conventional asphalt binder mixtures. Example 2 In this example, similar to that described in Example 1,
Portable mixing equipment for pumping and mixing molten sulfur and asphalt was transported by truck to a road paving site located approximately 2400 miles (3860 km) from the portion used in Example 1.

At this new location, the equipment was used with a mobile continuous asphalt mass mixing unit for the production of road foundations and surface layers. Because of the significantly colder winter conditions to which the road is exposed, the Anufart used for construction is much smaller than the 85-100 pen used in the example above.
AlbertaDepartment, not grade
OfHighway and TranspOrtOI)
It was a softer pavement asphalt that met Specification AC275. Typical properties of this grade of pavement asphalt were as follows. The aggregate used for paving was sieved crushed gravel.

A sieving test of the aggregate revealed that substantially all of the 15
．． It was shown to pass through a {'7 sieve with an 8 mm aperture and substantially less than 5% passed through a 200 mesh screen with a 0.074 mm aperture. Standard AC27 for use with the assembly as per the marshal test results.
The optimum ratio of 5 asphalt binder was found to be 6%. The marshal stability for such a mixture was approximately 2450 pounds. Considering the higher specific gravity of the binder, using a 40:60 sulfur/asphalt binder at an optimal ratio of 7% by weight, the marshal stability is about 3650 lbs, an increase of about 49%. It turns out that it does. Using a 50:50 sulfur/asphalt binder at an optimum ratio of 8% by weight, the marshal stability was found to be about 6650 pounds, representing an increase of about 170%.

The example was carried out as part of the construction of a road area' to be paved with asphalt paving concrete, generally 6 inches (15?) above the subgrade (i.e., total depth).

A 2000 ft (609 m) section of this road was constructed using a sulfur/asphalt binder for paving instead of asphalt alone. One part of the test area is 40:
60 sulfur/asphalt binder at 7% by weight of the mixture, and one portion of this area
0? ) thick, with one section being 6 inches (15
CTL) and one part is 8 inches (2
It was constructed with a thickness of 0C7rL). 6 inch and 8
The inch sections were laid in two stages (IntwOlifts), the first being 4 inches (10 (7n)) and the second being 2 inches (5 cTn) or 4 inches (10 cTn) as required.

The other two sections of the road were paved in two stages with a 50:50 sulfur/asphalt binder at a thickness of 6 inches (15CTn), one part 7% by weight in the aggregate mix. of binder and one part contained an optimum ratio of 8 (:Ff) binder in the aggregate mixture. The sulfur/asphalt binder hot mixture is produced at a rate of 200 tons/hour (1820001<g/hour) by a sulfur/asphalt mixer connected directly to the spray nozzle of the mixing plant, and the binder The feed rate was manually controlled and matched to the aggregate feeder speed using a pre-calibrated metering pump in the sulfur/asphalt mixer. The temperatures of the binder components, binder mixture, and mass were adjusted and adapted to the ranges for the corresponding parameters given in the examples above. The hot mixture discharged continuously from the mixing plant was transported to the paving point by a group of trucks. The binder content of the hot mixture is measured using the Traxler Nucle Asphalt Content Gauge.
arAsphaltCONtentGauge) was periodically monitored throughout the operation. Construction of the area was carried out using conventional road paving equipment. A 50 foot (15 m) long transition section was provided between adjacent sections of different thickness. The remaining length was constructed using standard force methods for building the required 6 inches (15 cTrL) (total depth) hard surface roadway. Test areas with sulfur/asphalt binder in the aggregate mix were laid and compacted using the same equipment used to lay and compact the rest of the road, and regular asphalt binder in the mix was laid and compacted using the same equipment used to lay and compact the rest of the road. No problems were encountered due to the use of sulfur/asphalt binders instead. Thickness variation in roads constructed with sulfur/asphalt binders consists of varying thicknesses of sulfur/asphalt bonds having a specific ratio of binder to a specific composition laid down on a substantially homogeneous subgrade. It was designed to make it possible to evaluate the degree of durability superiority of contourito over ordinary asphalt contourito. Example 3 The example concerns the resurfacing of a previously constructed asphalt concrete pavement highway with a sulfur/asphalt bonded aggregate, 10 miles (16 km) of which required resurfacing due to different alterations and A 5,400 foot test area requires the use of 2 inches (5CTIL) of new overlay for one portion of its length and a 4 inch (10?) overlay for the remaining length. It required use.

The 4-inch overlay was laid in two rows of 2 inches (5 (7n)) each.

The sulfur/anuphart and aggregate mixing equipment and paving and rolling (compaction) equipment used in the above examples were approximately 35 miles (56 km) to different sources of suitable crushed gravel aggregates near the resurfacing site site. transported. One sieving test of the mass to be used showed that more than 95% passed through the 1,000-inch Nutareen with 15.8 mm apertures and only about 2% passed through the 20-inch Nutaline with 0.074 mm apertures.
It was shown to pass the 0 mesh screen. Marshall test data for the asphalt with the same grade of AC275 grade asphalt used in the example above confirms that the optimal ratio of standard asphalt binder for use with the asphalt is 6%. and the marshal stability of such a mixture is about 2
It was 100 pounds. Using a 40:60 sulfur/asphalt binder at an optimum ratio of 7% by weight, the marshal stability was found to be approximately 2700 pounds.

Using a 50:50 sulfur/asphalt binder at an optimum ratio of 8% by weight, the marshal stability was found to be about 4100 pounds, an increase of about 95%.

Using the asphalt/sulfur blending and mixing equipment with the aggregate binder mixing equipment described in the previous example,
) of 40:60 sulfur/sulfur with asphalt binder/
Approximately 1940 tons of asphalt bonded aggregates were produced.
The temperatures of the binder components, binder mixture and mass were adjusted and adapted to the ranges described in Example 1 for the corresponding parameters. The hot mixture discharged continuously from the mixing plant was conveyed to the paving point by a group of trucks. As in the previous example, the binder content of the hot mixture was monitored periodically. The hot mixture was applied to a single northbound lane of the highway at two locations as described above.
Laid as an inch or 4 inch overlay. The adjacent southbound lanes were similarly overlaid with a conventional Anuphart aggregate hot mix containing 6% Anuphart, which was produced in the same continuous aggregate mixing unit;
It was then laid using the same conventional paving equipment and compacted using the same conventional rollers. There are no significant differences in the laying and rolling of hot mixtures made with asphalt and sulfur/anuphart mixtures.
)) Ivy. The resurfacing operation showed that the performance (PerfOrmance) of asphalt-bonded and sulfur/asphalt-bonded high-temperature mixtures in the conventional pavement force method was equal, and the resulting resurfacing roads demonstrated the durability of the sulfur/asphalt-bonded pavement. was expected to show potential superiority. Example 4 The example shows that in a batch colloid mill, 85-100
The production of a 50:50 sulfur/asphalt binder containing pcn asphalt is described.

The specific equipment used was an Eppenbach mill (model Q-6) capable of homogenizing a total of approximately 15 liters per batch.
-B). A batch of 2000 grams of fluid asphalt heated to 300 T (149 deC) is poured into the mill and the maximum dimension opening (approximately 0,075 inches, 1
．． It was circulated therein with a gap set at 8 mm).

2000 grams of 300 CF (149 C) molten sulfur was slowly added to the mill as batch circulation continued.

When the addition was complete, about 20% of the total sulfur added was homogeneously combined with the asphalt by chemical reaction and/or dissolution, and the remaining 80% was dispersed in the asphalt phase as sulfur droplets. The resulting dispersion was withdrawn from the mill and the sample was visually inspected under a microscope. The particle size of the molten sulfur droplets dispersed in the asphalt phase was observed to be in the range of substantially less than 10 microns and on average in the range of substantially 4-5 microns.

A part of the batch is 275-300 views F' (135-14
Part 9 was maintained under light stirring at a temperature of C). The remaining 175 grams of sample as a binder was immediately placed onto a 2325 grams sample of suitably sized heated crushed stone aggregate sieved to approximately 300 CF (149, C) in a heated mixing vessel. The mixture was poured and mixed with a high-power stirrer to coat the binder onto the mass. When the mass was homogeneously coated with binder, the hot mixture was compressed by standard force methods to prepare samples for the Marshall Mix Design test. Additional samples were immediately prepared in a similar manner and the average mechanical stability of these samples was determined to be approximately 4400 pounds. A sample of the binder batch, maintained under light agitation at 275-3000F (135-149C) for approximately 1 hour, was then visually inspected under a microscope to determine whether any small amounts of molten sulfur were present therein. The average particle size of the drops has increased from that of the same material one hour earlier;
It was shown that some agglomeration of the sulfur droplets had occurred, with many of the droplets reaching a size of about 50 microns. Condensation and precipitation of the sulfur by continuing to keep the binder in the liquid phase was expected, and the sulfur droplets were expected to be larger than 50 microns. 1 of each of said parts of the batch
A 75 gram sample was then immediately mixed with a heated mass as described above to produce a marshall test sample and the marshal stability of the sample was determined. The average of the marshal stability was found to be approximately 4500 lbs, and was determined by (a) the retentivity of the physical properties of the binder with sulfur droplets up to 50 microns in diameter, and (b) within the liquid phase for up to 1 hour. The dispersion stability was demonstrated.

Condensation and settling of the sulfur droplets was found to be severe after 3 hours, making the material unsuitable as a binder for Anufalt concrete pavements. Many other embodiments of the various force methods described are also possible within the scope of the invention.

Claims (1)

[Claims] 1. In the method for producing a coated particle aggregate composition, (a) 25
a metered stream of fluid asphalt having a temperature ranging from 0 to 350°F (121 to 177°C);
a metered stream of molten sulfur having a temperature in the range of 10°F (121-154°C) to produce a
Form a blended stream having a temperature in the range of 121-154 °F (121-154 °C), where the metered stream is asphalt 75-154 °F
Blended at a ratio of 25 to 60 parts of sulfur to 40 parts,
(b) Mixing the above blended streams so that the sulfur is well dispersed in the asphalt so that the asphalt homogeneously dissolves a portion of the sulfur and otherwise combines with it and the remainder of the sulfur is 1 to 50 microns. (c) passing the resulting binder blend stream to 310° F. (154° C.) for a period of less than one hour; a coated particle aggregate composition characterized in that: (d) the resulting mixture is agitated to homogeneously coat the aggregate with a blended stream; How things are made.