SU1276724A1 - Method and apparatus for preparing bitumen-mineral mixture - Google Patents

Abstract

The invention relates to the road construction and building materials industry, in particular to the preparation of bituminous mineral mixtures for the construction of foundations and road pavements. The invention is aimed at improving the physico-mechanical properties and reducing energy consumption. This is achieved by the fact that, before mixing the bitumen with the mineral material, the foaming of the bitumen is prevented by introducing into it hydrophilic surfactant substances (surfactants) in the form of a weakly concentrated solution. The preparation of the bitumen-mineral mixture is carried out in a mixer with generators-sprayers mounted on its lid, in which the bitumen is foamed with water of the surfactant solution and combined with the latter. Water with surfactant before being introduced into bitumen is heated partially by heat extracted from bitumen by means of heat connected to each spray generator (L of the exchanger. 2 cf f-ly, 3 dl., 1 tab.

Description

Yu

05

| Yu

The invention relates to the road construction and building materials industry, in particular, to the preparation of bituminous and mineral mixtures used in the construction of coatings and foundations of roads. The purpose of the invention is to increase the physicomechanical parameters and reduce energy consumption. FIG. 1 shows the proposed device for implementing the method of preparing the bituminomineral mixture, general view; in fig. 2 - spray generator, incision; in fig. 3 shows section A-A in FIG. 2. A device for preparing a bitumen-mineral mixture contains a stirrer 1 with a cover 2 and paddle shafts 3. On the cover 2, spray generators 4 are installed, to which pressure bitumen conduit 5 and conduit 6 are connected to supply water with surfactant additives. On the conduit 6, a pump 7, a shut-off valve-regulator B and a check valve 9 are in series installed, preventing the backflow of water with surfactant additives in the event of overpressure of the bitumen when foaming over water pressure. A supply pipe 11 is connected to the pressure conduit 6 through a shut-off valve-regulator 10. Each generator-sprayer 4 is made in the form of a hollow cylindrical body 12 with a lid 13 and a mixing chamber 14 located in the lower part of the body 12. A hollow conical tip 15 with slots for the passage of foamed bitumen is installed under the mixing chamber 14. The housing 12 has a tap 16, and on its cover 13 of the housing 12 is fixed a sleeve 17 with a clearance relative to the housing 12 and a cap nut 18 with a needle 19. The sleeve 17 is equipped with a fitting 20 located inside the outlet of the housing 16. In the gap between the inner surface of the housing 12 and the sleeve 17, a distribution washer 21 with holes for the passage of bitumen is located above the mixing chamber 14. In the cone tip 15 there is a pressure valve in the form of a steel ball 22, pressed by a spring 23 to the central opening of the partition 24 of the mixing chamber 14 and closing it. Each generator-sprayer 4 is connected to the pressure bitumen line 5 and the conduit 6 through a heat exchanger 25, which is an internal pipe 26, coaxially located inside the external pipe 27. The internal pipe 26 is connected on one side with a cable 20, and on the other - with a conduit 6. The outer tube 27 is connected on one side with the outlet of the body 16, and on the other with the bitumen conductor 5. A device for carrying out the proposed method for preparing a bituminous-mineral mixture works as follows. The mixer 1 is filled with mineral material 28. Water at ambient temperature, its air is supplied by pump 7 through conduit 6 to the shut-off valve-regulator 8. At the same time, pump 7 through pipeline 11 and conduit 6 to the shut-off valve - regulator 8 is fed hydrophilic surfactants. In this case, surfactants, for example of the imine type, are dissolved in water. The surfactant flow rate is controlled by the shut-off valve 10, and the resulting surfactant solution flow rate is controlled by the valve 8. The surfactant solution then flows through the non-return valve 9 to the heat exchanger 25, through the inner tube 26 of the heat exchanger 25 and the fitting 20 to the inside of the inner sleeve 17 and further to the mixing chamber 14. At the same time, the flow of the surfactant solution into the mixing chamber 14 is controlled by raising or lowering the needle 19. At this time, bitumen 5, the outer pipe 27, the outlet 16 into the housing 12 and further through the holes in the washer 21 enters the mixing chamber 14 stand, and the surfactant solution is injected into chamber 14 in the form of an aerosol. Upon contact of the heated bitumen with the surfactant solution, it instantaneously foams, increasing in volume. The foaming process is regulated by changing the volume of the mixing chamber 14 by changing the rings - gaskets 29. Bitumen foaming is accompanied by an increase in pressure (water transition into the vapor state, under the action of which the pressure valve spring 23 is overcome, the ball 22 moving away from the opening in the partition wall 24 of the mixing chamber 14 and the bitumen in the form of a uniform fine foam is injected through the side openings of the conical tip 15 into the mixer 1 filled with mineral material 28, which is The bladed shafts 3 are mixed with foamed IM bitumen. / 7. The preparation and testing of a bitumen-mineral mixture of the following composition,%: mineral material 93.93, bitumen 6.01 (6.4% by weight of mineral material), water-soluble surfactant (polyethyleneimine) 0.06 (1% of the mass of bitumen). Bitumen at 140-150 ° C along the bitumen line 5 and heat exchanger 25 was supplied to spray generators 4 under a pressure of 0.35 MPa. A surfactant (polyethylenimine) through a regulator valve 10 and a pipe 11 was supplied to the pump 7, to which the pressure conduit 6 was supplied with water at a temperature of ambient air. The content of surfactant in water was equal to 66.67%. The surfactant solution was pumped through the regulator valve 8 and the check valve 9 under a pressure of 0.45 MPa to the heat exchanger 25, where the water was heated by partially selected heat from the bitumen to 85 ° C. Water from the surfactant entered the sleeve 17 and sprayed into the mixing chamber 14. The bitumen was fed through the outlet 16 of the housing 14 and then through the openings of the washer 21 into the mixing chamber 14, where the bitumen was dispersed, mixed with water and surfactant sprayed, foamed and through the pressure valve The lateral openings of the tapered tip 15 fell on the mineral material 28 and were mixed with it in the mixer with 1 paddle shafts 3.

The obtained physico-mechanical properties of this mixture are shown in the table, which also shows the indicators of the physicomechanical properties of the bituminomineral mixture, obtained on the basis of a known method. 2300

1.7 5, 4 2.5

5.3 2.2

0.98 0.88 1.3

The implementation of the proposed method of preparing a bitumen mineral mixture and a device for drying it, practicing road construction, contributes to protecting the environment by reducing dust generation during the preparation of mineral binder mixtures.

Claims (2)

1. A method of preparing a bitumen-mineral mixture, which includes supplying heated bitumen and water, foaming bitumen with water and mixing bitumen with mineral material, characterized in that, in order to increase water resistance and reduce energy consumption, surface active substances are introduced into it during heating of bitumen. Water is produced by the heat that is partially taken off the bitumen at the time of its supply, and hydrophilic substances are used as surfactant in the form of a weakly concentrated solution. 2. A device for preparing a bitumen-mineral mixture, including an agitator with two bladed shafts and a lid, mounted on the lid generators-sprayers, each of which has a hollow cylindrical body with a conical tip, located in the body with a gap with a needle that overlaps its outlet orifice and is attached to a pressure bitumen body connected to a pressure pipe and a pressure valve, characterized in that, in order to increase water resistance and reduce energy consumption, it is equipped with An additional pipeline for surfactants is used, the casing of each generator-sprayer is equipped with a partition in front of the tip with a central hole and a perforated distribution washer and removable gaskets installed in the gap between the sleeve and the casing, the tips of the housings are made with openings adjacent to each sleeve part the conduit is coaxially placed in the bitumen pipe, and the pressure valves are mounted on partitions, blocking their openings on the side of the cone th tip.