A METHOD OF CLOSING CORES IN A CONCRETE CONSTRUCTION MEMBER, AND A DEVICE FOR APPLYING THE METHOD

Abstract: A method of closing at least one core (51) in a concrete construction member (50), comprising introducing a plug into the core in question through a wall thereof, wherein the steps of - making an opening in said wall before the plug is introduced into the core; and - bringing a fluid substance (65) through this opening, said substance being converted from fluid to solid to form the plug.

Description: This invention relates to a method of closing at least one core in a concrete construction member, comprising introducing a plug into the core in question through a wall thereof. The present invention further relates to a device for applying this method. Such a method and device are known from GB-A-2,174,639. It is conventional in the building art, especially in plant construction and the prefab building industry to use prefabricated concrete construction members whose cross-sectional shape and dimensions meet predetermined specifications and whose length may have a value to be chosen by the customer himself within given limits. In general, this is realized during manufacture by making concrete structural members that have a large length, e.g. 120 m, and sawing the members to size after hardening, in accordance with the customer's wish. To obtain a favourable ratio between the weight of the structural members, on the one end, and the strength thereof, on the other, the members are not solid but provided longitudinally with continuous cores. These cores are formed in the manufacturing process along the entire length of a construction member not yet sawn to size; consequently, when the structural members have been sawn to size these cores are in open communication with the outside air. The fact that the cores are open creates a number of problems when used in house building: 1) the cores form a possible cause of moisture and heat leakage through air transport; 2) the cores possibly contribute to noise polution, since sound can propagate through them; 3) there are building regulations which provide for dwellings to be gastight relatively to each other. Therefore, the cores should be closed. The device disclosed in GB-A-2,174,639 is combined to that effect with a device for manufacturing concrete construction members, with the concrete being extruded while the device is advancing. At predetermined places of the thus formed concrete construction members, the advance of the device is stopped, while extrusion continues, so that an amount of excess concrete is formed on the exterior of the wall of the construction member. This amount of excess concrete is then pressed inwards through the wall to form the plugs in the cores. A drawback of the known method and device is that it is thus only possible to fill the cores with the same concrete as that of which the construction member is fabricated. Another drawback is that the regular stopping of the manufacturing device results in a reduced production capacity, while it is not possible to close a selected, individual core and leave open others. Besides, the combination of the device for closing the cores, with the device for manufacturing the construction members means that the total device is highly complicated and that it is impossible to use the known device in conjunction with an existing, separate, concrete-slab manufacturing device. It is an object of the present invention to provide a method and a device which do not have the above drawbacks. In particular, it is an object of the present invention to provide a device with which it is possible to close a core in a concrete construction member in a simple manner. To that effect, a method according to the present invention is characterized by:making an opening in said wall before the concrete has hardened completely; and introducing the plug via said opening by bringing a fluid substance through said opening, said substance changing from the fluid to the solid state to form the plug. Preferably the closing is effected before the structural members are sawn to size. When the plug is then installed at or near a future saw cut, the quality of the plug can be inspected, after the concrete construction member has been sawn to size. It is advantageous when the opening in the wall of the core through which subsequently the plugging substance is introduced is made in the non-hardened condition of the concrete, since the piercing of the wall of a core requires little energy at that moment and because this offers the possibility of carrying out both operations, i.e. piercing and introducing the fluid, in one process stage. Forcing an opening in the wall of the core can be effected in a simple manner by performing a pricking movement with a suitable aid, but also by sucking or blowing away material through a first hollow guiding means adjacent the opening is a highly suitable way of forcing an opening. In this process, it is advantageous when the introduction means comprises a second hollow guiding means through which the substance is introduced into the core. When the method is employed when the concrete has hardened already, the opening is made preferably by means of a drill. The introduction of a substance into the core can be stopped when the pressure of the substance in the second hollow guiding means exceeds a predetermined level, or when a predetermined amount of substance has been introduced. Other features and advantages of the method and device according to the present invention will become apparent from the following description of preferred embodiments of the method and the device, read with reference to the accompanying drawings, in which: Fig. 1 is a cross-sectional view of a concrete construction member; Fig. 2 is a longitudinal view of a concrete construction member taken on the line II-II of Fig. 1; Fig. 3A-C are longitudinal sectional views showing a concrete construction member in three successive stages of the closing process; Fig. 4 is a cross-sectional view of a concrete construction member, together with a diagrammatic, part-sectional elevation of a first preferred embodiment of a closing device according to the present invention; Fig. 5A-D are longitudinal sectional views, showing a concrete construction member in successive stages of the plugging process; and Fig. 6 is a cross-sectional view of a concrete construction member, together with a part-sectional elevation of a second preferred embodiment of a closing device according to the present invention. Fig. 1 diagrammatically shows in cross-section a concrete construction member indicated in general by numeral 1. An upper face 2 and a lower face 3 are substantially flat and parallel to one another. In practice, the side faces 4,5, shown in the drawing as flat and perpendicular to the top and bottom surfaces are shaped to meet practical requirements. In longitudinal direction of the concrete construction member, there are provided channels or cores 6. The cross-sectional configuration of said cores may be round but in general is elongate. In Fig. 2 the construction member is generally indicated at 10. Sealing plugs 11,12,13 are provided in core 6. Plugs 11 and 13 are disposed at respective ends 14,15 of the construction member in the core. Plugs 11,13 are provided before the construction member is sawn to size, at or near the place where the saw cut is made. Fig. 2 clearly shows that when construction member 10 is sawn to size, plugs 11,13 are also sawn through. It will be seen from the figure that the exact shape of the free surface 16,17 of plugs 11,13 as well as the minimum thickness D1,D2 of plugs 11,13, measured from the end 14,15 of the construction member is not critical for providing a sealing effect. The plug 12 is not provided at an end of the construction member. Such plugs can be fitted at a predetermined place in a construction member to ensure that, when subsequently an opening is made at that predetermined place, there is a sealing plug at that opening; such a plug, however, may also serve for reinforcing the construction member. Filling holes 18,19 for introducing the substance are filled with the same substance as that from which the plug is made. When the construction member is sawn to size, the filling hole can be removed (as at 14) but the filling hole can also be present after sawing (as at 15). Figs. 3A-C are diagrammatic longitudinal sectional views showing a concrete construction member 30 in three different phases of the closing process, together with a cross-sectional view of a plugging device 40 according to the present invention. The walls 31,32 of the core have not yet hardened, so that a filling hole can be made at 33 without much energy. The plugging or closing device 40 includes a tubular portion 41, which may be provided with a bevelled end 42, thus rendering this end 42 highly suitable for forcing holes in concrete not yet hardened. The hollow guiding means 41 communicates with a header or distribution vessel 43 containing deformable substance 45. Fig. 3B shows that at 33 a filling opening has been forced in the upper face 31 by a pricking movement of the suitable end 42 of the hollow guiding means 41. The end 42 of the hollow guiding means 41 is brought into the vicinity of the lower face 32. By means of a vibration motor 44, header or distribution vessel 43 and hollow guiding means 41 are set into vibration. As a result, the deformable substance 45 will move out of hollow guiding means 41, through hole 42 into the core. The consistency of substance 45 is such that this does not flow away into the core when the hollow guiding means 41 is retracted from the filling hole at 33, while under the influence of vibration motor 44, the substance 45 flows out of hollow guiding means 41 and forms a quantity 34 on the bottom 32, as shown in Fig. 3C. By retracting hollow guiding means 41 from hole 33 at a suitable speed, there is obtained a closing plug in the core. Naturally, the supply of substance 45 by the vibration motor can be discontinued as soon as the end 42 of hollow guiding means 41 has been retracted from the filling hole at 33; it may then be advantageous when substance 45 also plugs filling hole 33. Fig. 4 is a diagrammatic cross-sectional view of a concrete construction member 50, and a diagrammatic, part-sectional elevation of a first preferred embodiment of a plugging or closing device 60 according to the present invention. Closing device 60 includes a plurality of hollow guiding means 61 provided with ends 62 suitable for piercing not yet hardened concrete, the number of, and interspace between, which correspond with the number and interspace of the cores 51 in the concrete construction member 50. The hollow guiding means 61 communicate with a header or distribution vessel 63, and under the influence of a vibration motor 64, substance 65 can be moved out of distribution vessel 63 through hollow guiding means 61. The quantity of substance 65 in distribution vessel 63 is replenished from the buffer vessel 66 by means of the pump 67. Forcing holes in the side walls of cores 51 and subsequently filling cores 51 with substance 65 takes place virtually synchronously. To that end, distribution vessel 63 is connected to means 68,69, serving for moving distribution vessel 63 vertically. Means 68,69 may be any suitable means as are well known in the art. In order for closing device 60 to be moved longitudinally of the construction members, across the construction members, this is provided with wheels 70. A control unit 71 serves for providing control signals to pump 67, vibration motor 64 and the vertical movement means 68,69 in order to control the filling process depending on the nature of substance 65, and the dimensions of cores 51, while the parameters can be entered manually in advance. The vertical movement means 68,69 are so controlled by control unit 71 that the ends 62 of hollow guiding means 61 are moved from a position near the underside 52 of the core to be filled to a position near the top 53 of the core to be filled. The rising speed is dependent upon the dimensions and the configuration of the core concerned. The introduction of the substance is stopped when the pressure measured by a pressure sensor 72 provided in the distribution vessel exceeds a predetermined value, or when end 62 of hollow guiding means 61 has traversed a predetermined distance from the underside 52 of the core to be filled. If desired, it is also possible to determine the amount of substance to be deposited in the cores by means of dosing devices 73. Although it is preferable that the plug is made before the concrete has hardened, it is also possible according to the present invention to fit the plug after the concrete has hardened. In that case, it will be necessary to drill the filling hole through the wall of the core, which requires considerably more energy than the removal of not yet hardened concrete. In general, this possibility will only be used as an emergency or repair measure. It will be understood that the method and apparatus 60 can be adjusted and/or modified in details in points obvious to those skilled in the art, without departing from the scope of the present invention. For instance, it is possible not to move the entire distribution vessel 63 in vertical direction but only the hollow guiding means 61, it being unnecessary for the hollow guiding means 61 to be moved all simultaneously. It is likewise possible to measure the pressure in each hollow guiding means 61 separately. Figs. 5A-D are diagrammatic, longitudinal views, in four different phases in the plugging process, of a concrete construction member 80 having a core 84, together with a cross-sectional view of a closing device 90 according to the present invention. Closing device 90 includes a storage vessel 91 filled with substance 92. The bottom 93 of storage vessel 91 contains a hole 94 through which a piston 95 can be moved. In the upper position of piston 95 shown in Fig. 5A, the end face 96 of piston 95 shuts off hole 94, so that no substance 92 can leave storage vessel 91 through hole 94. Fig. 5B shows that at 83 in upper wall 81 there is forced a hole corresponding with hole 94 in storage vessel 91 by lowering piston 95. Through the resulting hole 83 flows substance 92 into the core 84, which is stimulated because piston 95 has been set into vibration by a vibration motor, not shown. When the vibrating piston 95 is lifted again, the substance flows also underneath the end face 96 of piston 95 (Fig. 5C). When finally piston 95 has returned to the upper position (Fig. 5D), the substance 85 flowed into core 84 forms the plug, while also hole 83 is closed. Storage vessel 91 can now be lifted for it to be moved to a different position relative to the construction member 80. Fig. 6 is a diagrammatic, cross-sectional view of a concrete construction member 100 and a diagrammatic, part-sectional elevation, showing a second preferred embodiment of a closing device 110 according to the present invention. Closing device 110 includes a storage vessel 111 having holes 112 and pistons 113, the number and interspace of which correspond with the number and interspace of cores 101 in the concrete construction member 100. Comparable with the closing device 60 shown in Fig. 4, storage vessel 111 is coupled with a buffer vessel, not shown, while likewise there are provided means 114,115 for moving the storage vessel 111 in vertical direction, and wheels 116 for moving the closing device 110 longitudinally of the construction member 100. Pistons 113 are coupled with a vibration motor 117 and with a device 120 for vertically moving pistons 113 relatively to storage vessel 111. The operation of the vertical transport means 114,115 and 120 and of vibration motor 117 is controlled by a control unit 130, so as to control the filling process, in dependence upon the nature of substance 118 in storage vessel 111, and upon the dimensions of cores 101, while the parameters can be entered manually in advance. It will be understood that an embodiment wherein the pistons are moved independently from each other likewise falls under the inventive idea. Furthermore, the inventive idea is not limited to the shape of pistons shown. The only requirements set to the pistons are the possibility of shutting off hole 94 in a first position and of allowing the substance to pass in a second position. Although any liquid substance capable of hardening is suitable for use in the method according to the present invention, a mixture of fly ash and cement is preferred, since this material adheres well to concrete, both in the hardened and in the not yet hardened condition of the concrete, while it moreover has the required properties as regards viscosity and hardening capacity. The fact that fly ash is a waste product is an additional advantage.

Claims: A method of closing at least one core (6) in a concrete construction member(1;10;30;80), comprising introducing a plug (11,12,13) into the core (6,84) in question through a wall (31,81) thereof, characterized by the steps of making an opening (33,83) in said wall (31,81) before the concrete has hardened completely; and introducing the plug via said opening (33,83) by bringing a fluid substance (45,85) through said opening (33,83), said substance (45,85) changing from the fluid to the solid state to form the plug (11,12,13). A method according to claim 1, characterized in that the opening is made by drilling. A method according to claim 1, characterized in that the opening (83) is made by a pressing operation by means of a piston (85). A method according to claim 1, characterized in that the opening (33) is made by a sucking or blowing operation via a first hollow guiding means, through which material is sucked or blown away from the area of the opening (33) using air pressure differences. A method according to any of claims 2-4, characterized in that the substance (45) is brought into the core (6) via a second hollow guiding means inserted through the opening (33). A method according to any of claims 1-5, characterized in that the substance (45,85) is brought into the core (6,84) under the influence of vibrations. A method according to any of claims 1-6, characterized in that the substance (45,85) is a thixotropic substance. A method according to any of claims 1-7, characterized in that the substance (45,85) is a mixture of fly ash and cement. A method according to any of claims 1-8, characterized in that the opening (33,83) in the wall (31,81) of the core (6,84) is also, at least partially, filled with the substance (45;18,19). A method according to any of claims 5-9, characterized in that the introduction of the substance (45) is stopped when the pressure of the substance (45) in the second hollow guiding means exceeds a predetermined level. A method according to any of claims 1-9, characterized in that the introduction of substance (45) is stopped when the quantity of substance (45) introduced exceeds a pedetermined level. A method according to any of claims 5-11, characterized in that the end port of the second hollow guiding means is transported from a position near the bottom of the core (6) to a position near the top of the core (6), during the introduction of the substance (45). A method according to claim 12, characterized in that the transport speed of the second hollow guiding means is controlled in accordance with the proportions and the profile of the core (6). A method according to claim 12 or 13, characterized in that the transport speed of the second hollow guiding means is substantially constant. A method according to any of claims 12-14, characterized in that the introduction of the substance (45) is stopped when the second hollow guiding means is transported over a predetermined distance. A method according to any of the preceding claims, characterized in that the opening (33) in the wall (31) is made substantially in the area of a future saw cut, before the construction member is sawn, so that the plug (11,13) is also sawn when the construction member (10) is sawn. A device (40,60) for applying the method according to any of claims 1-16, characterized by: first hollow guiding means for making an opening in the wall of a core; second hollow guiding means for introducing a substance (45;65) into the core via the opening; and vibration means (44,64) for vibrating the second hollow guiding means in order to control the transport of the substance (45,65) into the core. A device according to claim 17, characterized by sucking means and/or blowing means to suck and/or blow air through said first hollow guiding means. A device according to claim 17 or 18, characterized in that the second hollow guiding means and the first hollow guiding means have a common guiding part (41,61). A device according to any of claims 17-19, characterized by a pressure sensor (72) for measuring the pressure in the second hollow guiding means. A device according to any of claims 17-20, characterized by transportation means (68,69) for transporting the introduction means vertically in the core. A device according to claim 21, characterized by control means (71) for controlling the transport speed of the introduction means. A concrete construction member, in which at least one plug is introduced in at least one of the cores, using the method according to any of claims 1-16.

Inventors: FAFIE, ROBERT GERARDUS, Fafié, Robert Gerardus
Applicants: VBI ONTWIKKELING B.V.
Application year: 1989
Main classification: B28B11
IPC codes: B28B11