SE441938B - PROCEDURE FOR PREPARING A PRESSURE HALL FIXED AND HIGH-STABLE COATING MASS FOR HIGHLY LOADED SURFACES - Google Patents

Abstract

A method of manufacturing and a use of a compression resistance and high stable surfacing mass for heavy loaded surfaces, especially for strong traffic and heavily loaded street and road sections and mainly comprising a stone material which is bound by an asphalt mass. The surfacing mass is manufactured by heating asphalt at least to the recommended temperature for mixing asphalt with a stone material, and before or after the admixing of asphalt with the stone material a fibre material is added, especially a mineral fibre having an average fibre diameter of between 1 mu m and 5 mu m in an amount of about 0.5-20% of weight in relation to the asphalt weight, and the fibre material is mixed homogenously so as to throughout provide substantially separate fibres in the asphalt phase. When admixing the fibre material before adhesion of the asphalt to the stone material the temperature of the asphalt is preferably increased to 20-40 DEG C above the temperature for mixing the asphalt mass into the stone material, and after a homogenous mixing of asphalt and fibre the asphalt mass is cooled to the said admixing temperature, whereupon the asphalt-fibre mass is mixed homogenously with the stone material.

Description

8009021-0 the particles in the rock material have less opportunity to regroup The fewer stones that participate in the load transfer.

However, the demands on the properties of the binder are increasing in corresponding degree, and in reality has the character of the binder has become the most important for the stability of the coating mass the factor. It is thus essential that the adhesive locks the stone. the particles effectively in their ingested positions and prevents shootings or regroupings of the rock particles. Binding The ability to bind can be increased by a larger amount of binder in relation to the amount of stone material added. Then arises however, problems with so-called asphalt runoff, which means that the hot asphalt during the mixing with the stone material flows of the rock particles, which partly counteracts the purpose of the search for funds, and also causes problems with storage and port. The stability of the coating mass is not significantly increased due to so-called cold flow in the asphalt.

Attempts have been made to solve this problem by appointment of a fine-grained filler material, but the result appears not be satisfactory. Apparently, the skeletal principle lost with the addition of fine-grained filler material.

Attempts have been made to solve the problem by appointment of asbestos fibers. Asbestos fibers have not been shown to provide skeletal sufficient adequate stability coverage with the concentrations technically can be used. This is probably due to the asbestos fibers their ability to hook into each other and form larger units.

Knowledge of the health hazards of asbestos fibers makes it except for the use of asbestos in road surfaces.

Swedish patent 211,163 also describes a laying material, which contains mineral fibers with a diameter of between 5 and 15 pm. Nor the proposed ones coarse mineral fibers have proven useful. Probably ten- they orient themselves parallel to the stone surfaces of the asphalt the rock mass and thus in the plane of the binder film. They contribute 8009021101 then hardly to the stability of the skeletal mass. None of them The proposed methods have therefore come to a greater extent practical use.

It has now surprisingly turned out that an appointment of a mineral fiber material with a small fiber diameter, preferably a fibrous material with an average diameter sam is less than 5 μm, and where the fibers are evenly distributed in the asphalt mainly as individual fibers, greatly decreases or eliminates the above-mentioned binder or asphalt cold moving problems. This gives a binder phase properties that give the finished coating mass significantly increased stability compared to previously known coating masses without the viscosity at the mixing temperature becoming too high for a quick and good mix. The increased stability The density is due to an increased strength of the binder, which probably is partly due to the increased thickness of the binder film around the stone grains, partly also because the added fiber material material, which is evenly distributed as individual fibers in the asphalt, has a reinforcing effect.

Many different types of materials can be used as fibers provided that the fibers do not melt in the asphalt, which below the mixture with the stone material maintains a temperature of 140-170 or preferably 150 DEG-160 DEG C., eeh while fawfeaffning a the fibers are relatively rigid and retain at least one significant stiffness in the hot asphalt. As particularly suitable mineral materials have been found, such as rock fibers, i.e. fibers produced by smelting stone such as diabase and subsequent fiberization of the melt. m mentioned above should be the average fiber diameter When the average fiber diameter Såso be less than 5 pm. falls below 1 pm reduces the beneficial effect of the fibers_ noticeably probably due to the fact that thin fibers inevitably shorten 8009021-0 significantly during the mixing operation. The average the fiber diameter should therefore be between 1 and 5 μm. In order to give the desired effect, the fibers should be added in bulk if between 0.5 and 20 X of the asphalt weight, which corresponds to approx. for 0.03 - 1.2% by weight of the finished coating composition.

It is essential that the fibers are not present in the form of tussles or other assembled units. This can be achieved by a properly performed mixing technique. To make it easier the distribution of the fibers and avoid tussle formation and to achieve an optimal wetting of the fiber surfaces with asphalt it can be advantageous that the fibers are surface treated with something suitable average. All kinds of non-colored compounds can be used for this purpose, for example wetting agents such as cationic surfactants in the form of tertiary or quaternary ammonium compounds.

It is also advantageous for the fibers to be as dry as possible when mixed with the asphalt, and in order to achieve an effect using the said treatment with wetting agent, it may be involved that before the mixing of the fibers in asphalt or the coating mass dries the fibers so that the majority of the aqueous molecules that are normally absorbed to the surfaces of the fibers lies.

The mixing of the fibers can take place by addition to the rock material before the asphalt is mixed into them, or the fibers can be blended into the finished asphalt stone mass.

However, a particularly good effect is obtained if the fibers are mixed with the asphalt mass before it is added to the stone material.

This facilitates the mixing and homogenization of the fibers. and the mixture of fibrous and asphalt materials can take place on one for the fibers very gently sweet, so that the fibers do not broken.

- An even and tuss-free distribution of the fibers in the asphalt 8009021-0 further benefit from the asphalt in connection with the mixing of eg 20-40 ° C above the temperature of about 150-160 ° C, and stone material takes place, the fibers are heated, in which the mixture of asphalt after the asphalt-fiber mixture is cooled to this temperature and involved in the stone material. The temperature rise lowers the viscosity the density of the asphalt and thus facilitates a homogeneous and gentle mixing of the fibrous material, and further facilitated at this elevated temperature the wetting of the fiber surfaces, and the dispersion of the fibers in the asphalt is faster and takes place more efficient.

In order to assess the impact of the fiber The material on the stability of the asphalt pavement was produced a number fiber pulps according to three different methods and within each group with different amount of fibrous material involved.

Example 1 In a mixing plant for asphalt masses was introduced 3,100 kilograms of rock mass with a certain given distribution of it average grain size. The stone material was heated to 160 ° C, and to the stone material was added 5.8 kg of a mineral fibrous material called "INORPHIL 057", which material has a average fiber diameter of about 3 μm, and in which the majority of the fibers are in the range of 1 - 5 pm.

There are none for the characterization of the fiber length acceptable direct methods. Suitably, the so-called the speed thickening number (nf), which is calculated by the equation nf = §- | 1Û 0 where H is the viscosity of a slurry of 1.5 g dry fiber in 200 ml of ethylene glycol at 20 ° C, and where no is the viscosity of the same ethylene glycol without fiber also at 20 ° C measured with the same equipment, namely Brohkfile viscometer with spindle 8009021-0 LV1 or equivalent. For "INORPHIL 057" the thickening 1.0 - 5.0.

To the mixture of stone material and fibrous material 195 kg of asphalt was mixed.

After mixing, the mass and its stabilization were taken out. small or after-packing tendency was met. This is done according to the following method: A bagged amount of coating compound is laid out in a frame of angle steel 80 x 80 mm, The frame, whose length is 2,000 mm and width 400 mm lies on a concrete floor. The coating composition insulated from the concrete floor with an aluminum foil.

After two days at about 18 ° C, the altitude position is measured for eight points along the center line of the rom in relation to the frame.

The mutual distance between the points is 200 mm. The meeting point consists of a 20 mm circular washer which is placed on the measuring the point.

Then a cylindrical roller with a width of 100 mm is rolled and the diameter 350 mm loaded with 200 kg five times in front and five times again over the mass along the center line. The the mentioned measuring points are measured again and the difference compared to the original measure is used as a measure of mass after-packing. The values are compared with the repacking in one normal mass, using the following valuation basis: "norma1", 0.8 - 1.2 x deformation of the normal mass "certain post-poking", 1.2 - 1.6 x normal mass formation "clear repackaging", more than 1.6 times the normal mass deformation. 8D09021: 0 In this case, the sample showed a clear tendency to repack.

Examples 2 - 6 Example 1 was repeated with the same type of mineral fiber but with different amount of fiber involved. The amount of admixture and the result is reported in the table below.

Examples 7 - 9 In these examples, the mineral fiber material was mixed in the heated asphalt before the asphalt-mineral fiber mixture is was added and mixed into the stone material. Results reported shown in Table 3 below.

Examples 10 - 12 In these examples, the asphalt was heated to 190 ° C, after which the mineral fiber material was mixed into the asphalt, asphalt-mining The fiber mixture was cooled to 160 ° C and mixed into the rock the material. The results are reported in the table below.

Example 13 In this example, mineral fibers were used as a comparison with an average diameter of 6 - 8 pm, but otherwise fos in the same manner as in Example 1 above.

Example 14 In this case, the same type of mineral fiber was used as in examples 1 - 12 above, but to determine the effect of fiber length, the fibrous material was ground so that it had a thickness number of 0.2, 8009021-0 Chart Example Fiber type kg fibers X of the asphalt Post-packing 1 INoRPHIL 057 0.6 0.3 z Clear 2 "1.2 0.6 z fish 3 "3.9 2.0% Normal 4 "13.6 7.0 X Normal 5 "39.0 20.0 X Normal 6 "58.5 30.0% Normal 7 INORPHIL 057 0.6 0.3% Certain 8 "1.2 0.6% Certain 9 "3.9 2.0% Normal 10 INORPHIL 057 0.6 0.3% Certain 11 "1.2 0.6 X Normal 12 "3.9 2.0% Normal 13 grave 6-8 pm 13.6 7.0% Clear í14 INORPHIL mald 13.6 7.0 1 Sure / Clear The table above shows that the smallest amount blended fiber is of significant importance for the stability or repacking tendency. In case of a mixture of * 0.3% by weight of fibrous material of the specified type is obtained according to examples 1 - 6 a clear after-trend and according to examples 7 - 12 a certain after-popping tendency. I de cases where the mixing percentage is approximately 0.5 or higher, on the other hand, you get a normal repacking. This applies especially when the mixing takes place according to examples 7 - 9 respectively 10 - 12. The table also shows that burial fiber according to Example 13 gives a clear packaging tendency, and that soo9o21,0 thus fiber having an average diameter of less than 5 μm has significantly better properties than coarser fibers. The table also shows that the fiber length has some effect, by the ground fibrous material used in Example 14 gives a noticeable repacking trend.

The attached drawing schematically shows a plant for preparation of the coating composition according to the invention. In a tank 1 equipped with heating coils 2 heats an asphalt mass 3 more normal mixing temperature or, as mentioned above to a temperature which is 20-4006 above this mixing temperature.

The hot asphalt is pumped by means of a pump 4 batches over in a mixing container 5, which is provided with a stirrer 6, and to which mineral fibers are added batchwise from a holder 7. After stirring until a homogeneous mixture is pumped the asphalt fiber mass by means of a pump 8 through a heat exchanger 9, where the temperature of the asphalt-fiber mixture is corrected to correct mixing temperature with the rock mass. In the event that the mixture of asphalt and mineral fibers occurred at elevated temperature the mass is cooled, and in the event that the mixing has taken place at the normal mixing temperature of, for example, 150-160 ° C and some cooling may have occurred during the handling of the mass, a certain temperature-raising correction may be necessary.

The stone material is heated in a container 10 provided with heating means 11 and is transferred therefrom batchwise to a rotary mixer drum 12. The one from the mixing container 5 for asphalt and mineral fiber coming mass is also pumped batch through the heat exchanger 9 to the mixing drum 12 and mix with the stone material at the same temperature on the two phases.

As mentioned earlier, the mineral fiber material can be fed directly from the mineral fiber container 7 to the mixing drum man 12 for asphalt and stone material, and in this case pumped of course the asphalt also directly from the asphalt tank 1 to the mixed ningstrumman 12. 8009021-0 10 It is understood that the above description and the plant shown in the drawing is for illustrative purposes only examples, and that many different modifications may occur within within the framework of the following potent requirements.

Claims (6)

--_- f s * | .mg n 8009021-0 P a t e n t k r a v A process for producing a pressure-resistant and highly stable paving compound for heavily loaded surfaces, preferably as paving for streets and roads, in particular paving at street crossings, before traffic lights, in traffic roundabouts and other heavily trafficked traffic points, which paving material mainly contains a stone material is bound by an asphalt mass, whereby asphalt (3) is heated to a temperature at least corresponding to the recommended temperature for mixing the asphalt with stone material, in parallel the stone material is heated to the recommended mixing temperature, the heated asphalt and the heated stone material are mixed to a homogeneous mixture in the proportions 15-25 parts by weight of stone material. per part by weight of asphalt, / characterized in that during the handling 0.5 - 20% by weight is added calculated on the amount of asphalt of a fibrous material with an average fiber diameter of between 1 and 5 μm and of a type which does not dissolve or soften in any significant degree in the hot mass, and that the fibrous material is treated with a wetting agent, e.g. cationic surfactant before adding the fibrous material to the asphalt. 2. A method according to claim 1, characterized in that the fibrous material consists of mineral fibers, and in that the fibrous material is added to the heated asphalt and mixed into a homogeneous mass of fibers dispersed in the asphalt before the asphalt is mixed into the stone material. Process according to claim 2, characterized in that the asphalt is heated to a temperature which is 20-40 ° C above the recommended mixing temperature for asphalt rock mass before the addition of the fibrous material to the asphalt or before the mixing of the asphalt and the fibrous material to the homogeneous mass. A method according to any one of claims 1, 2 or 3, characterized in that the fibrous material is completely dried before the addition to the asphalt material. soo9q21-o 12 5. ' Process according to one of Claims 2 to 5, characterized in that the asphalt-fiber mixture is cooled to the recommended mixing temperature before the asphalt-fiber mass is mixed with the stone material. 6. A method according to any one of the preceding claims, characterized in that the added fibrous material is selected from a group of materials with the thickening number according to the specified definition of between 1, 0 and 5.0.