FI81862B - Method of producing a concrete road - Google Patents

Abstract

The invention relates to a concrete road and a method of producing the same. The road is made from what is known as dry concrete mass which at the moment of laying has a flexibility of roughly 36 Vb° or more rigid than this or has a maximum water content of 90 l/m3. The dry concrete road is produced by a stone material 7 and cement 12 being fed separately in a mutually proportioned manner to a lowering silo 8 with an open bottom, where the stone material and the cement are mixed to form dry concrete mass which is continuously discharged via the open bottom 9 of the lowering silo to form a dry concrete layer.

Description

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Method for making a concrete road. - Förfarande för framställning av en betongväg.

The invention relates to a method for producing concrete roads from dry concrete mass. In this context, dry concrete mass means a mass which, at the time of application, has a flexibility of about 36 Vb ° or more, i.e. contains no more than 90 l / m · * of water.

The ground concrete used in the works has traditionally been produced in temporary concrete stations built in connection with aggregate depots. This has caused difficulty in getting a flexible and quick start to stabilization work. The water-cement ratio in the concrete thus produced has also been unfavorable, which, on the other hand, has meant that the amount of cement must have been disproportionately high in order to achieve the desired strength of the concrete.

Compared to the use of ground concrete, the dry concrete method, in which water is not actually added to the concrete at all, has been found in the study to be about 22-25% cheaper precisely due to the water-cement ratio. The mass to be applied is then 36 Vb ° or more rigid, i.e. it contains a maximum of 90 l / m 2 of water.

In road works, concrete usually has to be produced in moving quantities in several thousand cubic meters, so that the lower amount of cement required in the dry concrete method compared to earth concrete constitutes a very large part of the entire casting operation as a cost factor.

In the past, the dry concrete method has been used mainly for the manufacture of pipes, manhole rings and aisle slabs. The dry concrete method has not been able to be used at all in road construction - despite its considerable advantages - because there have been no suitable machines for its application.

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Strassen- und Tiefbau 6/1982 describes the preparation and mixing of dry concrete mass into a finished mass in a concrete plant, adding 4-6% by weight of water to the mass. The finished mass is transported to the road construction site, where it is applied and compacted in the usual way using separate spreading machines and compaction machines. Such production, transport, application and compaction of the pulp at different stages make the manufacturing process laborious and expensive.

U.S. Patent 2,201,493 discloses a pulp application and compaction machine with a combined mixing and downcomer. The silo contains overlapping mixing grids that must be rocked back and forth to allow the pulp to flow through the grids. If the silo were full of mass resting in the ground through the open bottom of the silo, the mixing grids could not be rocked. Thus, there is no mass in the silo other than that which, when fed momentarily, collapses through the mixing grids. The thickness of the cast layer is determined by the instantaneous feed rate of the pulp in relation to the flow rate. Such an arrangement would not be suitable for the purposes of the invention, since the dry concrete mass used in the construction of the road contains a relatively coarse aggregate which would block and break the grate mixers moving back and forth.

With the method according to the invention, when applying dry concrete, it is essential that the mass is in the landing silo in the ground space and the layer thickness is determined by the spreading blade limiting the open bottom of your landing joy.

A concrete road meeting sufficient strength requirements can be produced more economically by the dry concrete application method according to the invention, which is characterized in that the aggregate and cement are fed separately and relative to each other from the bottom to an open landing silo where the aggregate and cement are mixed into a dry concrete mass of about 36 that is, it contains no more than 90

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3 81 862 1 / m3, and that this dry concrete mass, which is supported in ground through the open bottom of the silo, is continuously lowered through the open bottom of the silo into a dry concrete slab, the thickness of which is determined by the spreading blade delimiting the silo bottom opening.

The structure and operation of the machine used to perform the method according to the invention will be described in more detail with reference to the accompanying drawing, in which

Figure 1 shows the machine seen from the side and partly open-sectioned.

Figure 2 shows an embodiment of a laahin device for finishing a surface made by the method according to the invention.

The machine for the production, spreading and compaction of dry concrete shown in Fig. 1 comprises a frame marked with reference number 1, the front end of which is supported by roller wheels 2 with tracked wheels and the rear part by a roller drum 3 and a vibratory roller 16. The roller wheels 2, roller drum 3 and vibratory roller 16 are via hydraulic cylinder devices 4, 5, 23.

By means of said piston-cylinder devices 4, 5, 23 the height and position of the body 1 relative to the ground can be adjusted and / or the body kept in the desired level by controlling the operation of the piston-cylinder devices 4, 5, 23 with a spirit level device 24 and a height scale 25.

At the front end of the machine there is a silo 6 for rock to be unloaded from the truck driving ahead. At the rear of the silo 6 there is a landing silo 8, the lower end of which has a transverse landing opening 9. The bottom of the aggregate silo 6 is formed by a belt conveyor 10 which feeds the aggregate 7 into the landing silo 8.

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At the top of the machine, above the landing silo 8, there is a cement tank 11, which is filled with cement fed from a tank car running on the side of the machine through a pipe 26. The lower part of the cement tank 11 has a dosing screw 27 and a closing flap 28, which adjust the amount of binder 12 to be fed to the downcomer 8.

In order to carry out the casting continuously in a so-called strip casting from a moving vehicle, an up-down-adjustable dam hatch 19 is provided for adjusting the mass flow of aggregate fed to the downcomer 8, whereby the mass flow can be controlled both by the damper 19 and by changing the speed of the belt conveyor 10. The amount of aggregate 7 entering the landing silo 8 is monitored by means of a mechanical device 29 measuring the thickness of the aggregate layer on the belt conveyor 10, which device is connected to an electronic measuring device 30. In addition, weighing sensors 32 are provided at the end of the belt conveyor 10 for measuring the amount of aggregate.

In the production of concrete meeting very high strength requirements, a laser measuring device 31 is used instead of a mechanical measuring device 29.

The mass flow measuring means 29, 31, 32 of the aggregate 7 control the operation of the dosing screw 27 and the shut-off flap 28 of the cement 12 so that the binder 12 fed to the downcomer 8 is in the desired ratio to the aggregate 7 to be fed.

The continuously fed aggregate 7 and the cement 12 enter the mixer 18 in the settling silo 8, whereby the aggregate 7 and the cement 12 are mixed in the settling silo 8 while the mixed dry concrete mass 14 is applied through the open bottom 9 of the silo 8. Between the discharge opening 9 and the mixer 18 there is a post-mixing member 13 which is rotatable about the horizontal axis of the machine.

The thickness of the layer 14 of the casting mass 14 coming from the downcomer 9 of the downcomer 8 is determined by the adjustable spreading blade 15 moving with the body 1. Behind the spreading blade 15 there is a compacting roller 16 compacting the casting mass and then a static roller for final sealing. towing device 17.

The machine according to the invention has two drive motors operating independently of each other (not shown), one of which is arranged to drive devices operating synchronously with the speed of movement of the machine and the other devices which are substantially independent of the speed of movement. The former motor provides power, for example, for the movements of the machine, for the movement of the door 19 and for the movements of the conveyor belt 10 and the dosing screw 27. The latter motor, in turn, handles the height adjustment of the body 1, the compaction by means of a vibratory roller 16, the operation of the drawbar 17 and the operation of the mixer 18.

In a preferred embodiment of the invention, a roller drum 20 is arranged between the roller drum 3 and the drag device 17 in communication with the tempering liquid tank 19. The rubber-coated roller drum 20 is moistened with the tempering fluid 21 by means of a filter 33. by means of rubber beads 34 resting thereon.

The tempering fluid reservoir 19, the roller drum 20 for dispensing the tempering fluid, and the drag device 17 are formed as a single unit to be raised and lowered relative to the machine body 1.

The traction device 17 has two or more traction planks 22 synchronously moving with each other, whereby the compression pressure of the traction planks 22 against the casting surface is adjustable by means of hydraulic piston-cylinder devices 36.

The invention has been described above with reference to only one preferred embodiment thereof. However, it is not intended in this way to limit the invention to this example only, but many modifications are possible within the scope of the inventive idea defined by the following claims. Thus, the coating layer may be cast as one solid slab or two slabs, the lower cement content of which may be lower than that of the upper tread.

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Claims (1)

A method for producing concrete roads from dry concrete mass, characterized in that the aggregate and cement are fed separately and relative to each other from the bottom to an open silo, where the aggregate and cement are mixed into a dry concrete mass with a flexibility of about 36 Vb ° or more, i.e. containing up to 90% water. l / m 2, and that this dry concrete mass, which is ground-supported through the open bottom of the silo, is continuously counted through the open bottom of the silo into a dry concrete slab, the thickness of which is determined by the spreading blade delimiting the silo bottom opening. 8 81862 Patent application for the production of concrete products in the form of concrete, in the case of cementitious materials in which the cement is used in a proportional manner, and in the case of the same material, in the case of cement and cement ° if the load is not more than 90 1 / m3 of water, and the tensile strength of the troughs is determined by the use of the markings, silons bot-tenöppninq. »* · Li