EP1907179A1

EP1907179A1 - Method for the manufacture of a concrete floor

Info

Publication number: EP1907179A1
Application number: EP06757810A
Authority: EP
Inventors: Christianus Petrus Wilhelmus Geurts; Derk Rogier Donkervoort
Original assignee: Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO; TNO Institute of Industrial Technology
Current assignee: Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek TNO; TNO Institute of Industrial Technology
Priority date: 2005-06-29
Filing date: 2006-06-27
Publication date: 2008-04-09
Also published as: WO2007001169A1; NL1029364C1

Abstract

Method for manufacture of a concrete floor. In a moulding jig (1) a first layer (3) meant as top layer is poured. After application of pre-stressed reinforcement (6) a second layer (7) meant as construction layer is poured on the first layer. On the second layer then a third layer (9) meant as ceiling layer is applied. After hardening of the layers the moulding jig is, inclusive of the from those layers constructed concrete floor, being turned and the concrete floor is released from the moulding jig. Savings as grooves (4) etc. can be obtained in the face of the concrete floor by means of core components (5) in the bottom of the moulding jig. In the construction layer concrete free channels (8) or veins can be applied by means of the pouring in of temporary core components, or permanent core components, e.g. of polystyrene foam. In the construction layer tubes and/or channels for sanitary and/or climate-related purposes can be applied. For the top layer (9) a sound-absorbing material can be chosen.

Description

Title: Method for the manufacture of a concrete floor

Field

The invention concerns a method for the manufacture of a concrete floor for application in house-, commercial and industrial building industry.

Background

A floor in a house normally serves as the supporting function of the living rooms. The floor is part of the skeleton of the house which is usually produced with stony materials. The technical installation of the house (as sanitary installation, underfloor heating, room heating, ventilation, electrical installation, community aerial system and data) can be partly fitted into the floor.

The functionality of the ground floor and the storey or roof floor is different; usually different types of floors are chosen for them. More and more floor heating tubes can be found in the ground floor, but hardly facilities for the electrical installation will be found. In the storey floor (and roof floor) there are very large stair wells and, more and more, facilities for the electrical installation.

The building process of a Dutch house is organized in such a way that no more plasterer is needed for the finishing of the concrete ceiling. The wooden floor, the floor with a slightly lowered ceiling and ceilings that must be plastered according to traditional methods have disappeared almost completely for the Dutch building industry.

Several building methods for houses can be distinguished: • Masonry method o The supporting walls consists then of stacked sand-lime bricks or elements. o The floor is then always produced with prefab concrete • Pouring work method o The supporting walls are poured into a steel shuttering which is relocated in a short time from house to house o The floor can be produced with prefab concrete or be poured too (it is then a matter of a tunnel shuttering)

• Prefab building o The supporting walls consist then of prefabricated concrete, often of large dimensions. o The floor is then always produced with prefab concrete • Timber frame building o The supporting walls consist then of stacked walls of prefabricated wooden walls. o Only for this building method a wooden floor is still applied, however in prefabricated version.

The attention of this invention goes to the bulk of the application, i.e. the prefabricated concrete floor, which is applied massively in three of the four building methods.

Characteristic of the current concrete floor is that these are supplied as semi-manufactured product. The underside of the floor is without intervention of a plasterer nearly finishing ready. The floors support freely from boundary wall to boundary wall. The element width is usually 1200 mm (concrete hollow-core slab floor) or 2400 mm (concrete broad slab floor). The difference is to be found in the constructive structure of the elements:

• The concrete broad slab floor o The supporting walls consists then of stacked walls or prefabricated wooden walls. o This is in fact a lost shuttering of 50 mm thick concrete with a width of 2400 mm. o In this concrete shell the reinforcement (pre-stressed or mild steel) is poured in by the concrete factory. o The shell floor is during the production process supported at several points of support o The contractor applies at this lost shuttering the necessary additional constructive reinforcement alongside and in cross direction and at the stair well and at the extremities a wooden joist shuttering. o The floor is at a certain moment being finished while pouring with concrete (mortar of the concrete supplier and construction crane) o After the required hardening time the support elements are removed and the floor's self-supporting function is realized. o Floor with a mild steel reinforcement are relatively weak, as a result of which the free span is limited at ca. 5 meters.

• The concrete hollow-core slab floor o This is an already from the factory self-supporting house- wide spanning floor of usually ca. 180 mm thickness or more and a width of only 1200 mm. o In order to save weight large hollow-cores alongside are left in the floor, which is made possible by the production with the help of an extrusion process on a long pre-stressing bank. o Because of the pre-stressing and the weight saving large free spans are possible. o Because of the limited width an (expensive) trimmer iron is required at a stair well. The order in which the assembly takes place must geared to that.

The building process of the two concrete floors has a number of similarities: • The constructive floor has a rough top. A concrete screeded floor or an anhydrite flow floor is needed in order to ensure a smooth top.

• The supply and drain lines for the WT installation (convectors in the facade, underfloor heating) are inserted in the screeded floor

• The central sockets (or savings for these) are already inserter in the concrete factory

• In the production no slab is the same

• More and more assembly takes place directly from trucks

Differences exist also in the building process of the two floors: • Electricity tubes for the electrical installation are inserted at the construction scene; for broad slabs poured into the construction floor, for hollow-core slabs in the concrete screeded floor.

• The facilities for the sanitary installation (tubes for toilet drainage and shower drainage) and air conditioning (as tubes for ventilation) are, at broad slabs, being poured in at the construction scene.

• At hollow-core slabs grooves are being saved in the concrete factory in order to be able to insert pipes and tubes. The locations of these grooves are not entirely free and the changing of the sanitary installation can only be done till a certain moment before production (differs per manufacturer).

• The stair well is, with broad slab, being formed by cross reinforcement which is poured in; with the hollow-core slab a separate trimmer iron is required.

All said proceedings are in the construction process of the concrete floors to be largely found on the critical (planning) path.

The Dutch building tradition concerning the electrical installation has a large effect on the building process of the floors:

• The electrical installation is constructed according tot a star system. o From the meter cupboard lines go to fourteen to sixteen central sockets in the constructive floor (at the underside accessible, at luminous points in the floor) o From the central sockets lines go to switches and wall sockets in the underlying living room. o The falling lines often continue to the wall sockets at ca. 300 mm above the underlying floor. The lines are being inserted in grooves in the walls (supporting and non-supporting walls). The grooving in concrete and calcium silicate provides a problem of crystalline silica. o The work of the electrician at the construction scene is therefore very fragmented and difficult to plan. He comes back at least 10 times per house. • Switches are made at 230 Volt, whereas in the neighbouring countries and the engineering since long more advanced switch techniques exist (switching in the meter cupboard and steering with bus system, low tension or wireless).

• The flexibility in the period between start and completion is limited and the articulate buyer is experienced more and more as a burden

• The flexibility, after completion of the electrical installation, of new techniques, data, entertainment, and domotics and making appropriate the housing by elderly people (domotics) leaves a lot to be desired.

the current floor systems a production process is used which is geared he building process:

• For which the screeded floor is inserted into the work. The attention for the smoothness of the top is minimal. • In the future sterner demands will be applied to the top than to the ceiling side. • The electrical installation is in ten steps inserted in the construction and is places partly in the constructive prefab floor (broad slab) and partly in the screeded floor to be applied on the work. • In the work there is always a need for components in order to form overhangs and stair wells (till 3500 large) (broader than the current floor width, 2400 mm for hollow-core slab en 1200 mm for broad slab and 1200 mm for concrete hollow-core slab floor). For broad slab floors extra reinforcement is applied in the pouring concrete. For hollow-core slabs a trimmer iron (steel beam) is used that takes care of the floors at the stair well.

• The production method of hollow-core slabs is optimized according to the "promptly ready" principle. The machines run over a stationary mould and let savings for weight saving. The working method leaves no room for the integration of reinforcement, pipes and sockets. Everything must be inserted after extrusion. Partly in the concrete factory, where digging in the still unhardened concrete (central sockets) happens and partly at the building scene by applying facilities into the screeded floor. • The production method for broad slab floors is, it is true, flexible, but requires much work (even understamping) at the place of building.

Summary The current invention aims to meet up with said described drawbacks.

For this purpose a new method is suggested hereinafter for the manufacture of a concrete floor which comprises the following steps: a. A moulding jig is provided; b. A first layer meant as top layer for the concrete floor is poured into the moulding jig, whether or not after the application beforehand of reinforcement into the moulding jig. c. After the next application in the moulding jig of pre-stressed reinforcement a second layer meant as construction layer of the concrete floor on said first layer is poured into the moulding jig. d. On the second layer a third layer meant as a ceiling layer of the concrete floor is then applied. e. After sufficient hardening of said layers the moulding jig is, inclusive of the from those layer constructed concrete floor, turned and the manufactured concrete floor is freed from the moulding jig and taken away.

In fact the whole concrete floor is thus being poured upside down into the moulding jig: first the top layer is poured, then the "body" of the floor, the construction layer, and finally the ceiling layer. As the bottom of the moulding jig is smooth, the first layer meant as top layer (which during production is thus laying against the bottom of the moulding jig) becomes splendidly smooth. The surface of the construction layer is in fact of little importance, whereas the as last to be poured third layer, meant as ceiling layer, can be finished sufficiently smoothly. This happens no longer at the beginning of the shell building phase but at the end of the completion phase, approximately 4 to 6 weeks before completion.

Preferably, grooves are being applied in the face of the concrete floor to be manufactured, e.g. for the afterwards inserting of electricity and/or other cables or installations tubes for cables and/or wiring, e.g. by means of core components etc. that are applied at the bottom of the moulding jig. After the manufacturing of the floor and its turning, the grooves thus come on the top of the floor, due to which the tubes, cables etc. can be applied from the top, after which the grooves are being filled up and finished off smoothly.

The pre-stressed reinforcement required for manufacture of the construction layer is preferably clamped at the moulding jig. The construction layer itself can be applied by means of extrusion of the concrete.

In the construction layer concrete free channels or veins are preferably applied by means of pouring in of temporary or permanent, non-concrete core components. The concrete free channels can be obtained by, after sufficient hardening of the construction layer, pulling (releasing) out the concerning core components, which are e.g. being formed by steel tubes with towing hitches at their extremities. The concrete channels can also be obtained by means of core components that remain in the construction layer and thus form concrete free veins in the construction layer. Such as concrete free veins acting permanent core components are e.g. manufactured from a solid foam material, as polystyrene or polyethylene foam. Both application, both that of "empty" concrete free channels and that of veins filled with e.g. polystyrene foam, intend to influence positively both the total mass and the thermal characteristics of the concrete floor.

As already noted, it is possible by means of core components at the bottom of the moulding jig, to apply grooves etc. in the first (top) later in the first layer of the concrete floor for electricity and/or other cables or installations tubes for cables and/or wiring. Also in the second (construction) layer tubes and/or channels, e.g.s for sanitary and/or climate-related technological (ventilation etc.) purposes, can be inserted namely by placing those tubes and/or channels after the pouring of the first (top) layer in the moulding jig and then pouring the second (construction) layer. In this way those tubes and/or channels in the second layer can be poured in. An alternative, especially to be used when also the room of the concrete free channels in the construction layer has to be used, is that after the pouring and sufficiently hardening of that second layer - or a part of that - and the releasing of the core components of concrete free channels, there were those tubes and/or channels have to come, to take away material of the second (construction) layer (e.g. by "digging in" or vacuuming away), after which the concerned tubes and/or channels can be inserted and the second layer then be poured over that.

Finally as material for the second layer a sound-absorbing material can be excellently chosen. This option is possible because the third layer, the ceiling layer, is applied at the end and - as the floor is manufactured upside down - does thus not need to get inserted the preceding, very heavy layers.

Exemplary embodiment

Figures Ia, Ib and Ic schematically show two cross sections of a moulding jig with a reproduction of the moulding process of a concrete floor at different stages. Figure 2 schematically shows the view from above of the moulding jig with in it the poured concrete floor.

Figure 3 schematically shows the moulding jig during the releasing of the concrete floor. Figure 4 schematically shows the view from above of the manufactured concrete floor.

Figure Ia shows a first step in the process of the manufacture of a concrete floor with the help of an iron moulding jig that, if required, has been strengthened with ribs 2. First a first layer 3 meant as top layer of the concrete floor is poured into the moulding jig 1, whether or not after the beforehand inserting into the moulding jig of a - in the figure not explicitly shown - top layer reinforcement. In the first layer grooves 4 etc. in the face of the concrete floor to be manufactured can be obtained by means of core components 5 that are being applied at the bottom of the moulding jig. The grooves 4 can e.g. be intended for the afterwards inserting of cables, lines etc.

Figure Ib shows how after the inserting of pre-stressed reinforcement 6 into the moulding jig a second layer 7 meant as construction layer of the concrete floor is poured into the moulding jig on the first layer 3. The pre- stressed reinforcement 6 is clamped on the moulding jig 1, which has been reinforced sufficiently for that purpose with e.g. reinforcement ribs 2. The construction layer 7 is preferably applied by means of extrusion of the supplied concrete.

Figure Ib (right) illustrates also that in the construction layer 7 concrete free channels or veins 8 can be applied by means of pouring in of temporary or permanent, non-concrete core components. These concrete free channels 8 can be obtained by after the sufficient hardening of the construction layer pulling out of that iron core components, due to which the channels 8 arise. Concrete free channels or address 8 can also be obtained by means of core components, e.g. of a solid foam material as polystyrene foam, which remains in the construction layer and thus form concrete free veins that produce weight saving and increase of insulation.

In the construction layer 7 also the (not drawn) facilities for the warmth and sanitary technical installation can be applied. With that the manufacturer can choose from two options: preceding the (entirely) pouring of the construction layer the application of the concerned facilities (pipes, cables, tubes) or afterwards, by means of "digging in" of those facilities and new pouring after the releasing of the core components for the channels 8. This applies also for (additional) reinforcement for lintels and stair wells.

Figure Ic illustrates that on the second layer 7 a third layer 9 meant as ceiling layer is applied. This can be of an other material than concrete, e.g. of plaster, or a porous material, in order to bring about better sound technical performances with that.

Figure 2 shows the moulding jig 1 with the poured in concrete floor, inclusive of the pre-stressed reinforcement 6 and the groove 4 and the core component 5 in the bottom of the moulding jig.

Figure 3 shows that the moulding jig, inclusive of the from the layers 3, 7 and 9 constructed concrete floor, after sufficient hardening of those layers

3, 7 and 9, is getting turned after which the so manufactured concrete floor is released from the moulding jig by the pulling up of the (turned) moulding jig 1. The floor then comes to rest on the bearing construction 10.

Finally, figure 4 shows the view from above of the concrete floor in released condition (note that the groove 4, caused by the in the moulding jig remained core component 5 is now situated on top of the concrete floor).

Claims

1. Method for the manufacture of a concrete floor, comprising the following steps: a. a moulding jig (1) is provided; b. a first layer (3) meant as top layer of the concrete floor is poured into the moulding jig, whether or not after beforehand inserting a reinforcement into the moulding jig; c. after application of a pre-stressed reinforcement (6) in the moulding jig on said first layer, a second layer (7), meant as construction layer of the concrete floor, is poured into the moulding jig; d. after hardening of the second layer a third layer (9), meant as ceiling layer of the concrete floor, is applied; e. after sufficient hardening of said layers the moulding jig, including the from those layers constructed concrete floor, is turned and the manufactured concrete floor is released from the moulding jig.

2. Method according to claim 1, wherein savings like grooves (4) etc. are obtained in the upper surface of the concrete floor to be manufactured by means of core components (5) which are being applied at the bottom of the moulding jig.

3. Method according to claim 1. wherein the under c. mentioned pre- stressed reinforcement is clamped on the moulding jig.

4. Method according to claim 1, wherein the construction layer is applied by means of extrusion.

5. Method according to claim 1, wherein in the construction layer concrete free channels (8) or veins are applied by means of pouring in of temporary or permanent, non-concrete core components.

6. Method according to claim 5, wherein concrete free channels are obtained by, after sufficient hardening of the construction layer, pulling out the concerned core components.

7. Method according to claim 5, wherein concrete free channels are obtained by means of core components that remain in the construction layer and thus form concrete free veins in the construction layer.

8. Method according to claim 7, wherein the as concrete free veins acting permanent core components are manufactured from a solid foam material.

9. Method according to claim 1, wherein in the second layer (7) tubes and/or channels for e.g. sanitary and/or climate-related purposes are being applied by placing those tubes and/or channels after the pouring of the first layer (3) into the moulding jig (1) and then pouring the second layer (7).

10. Method according to claim 1, wherein in the second layer (7) tubes and/or channels for e.g. sanitary and/or climate -related purposes are applied by, after the pouring and sufficient hardening of the second layer (7) or a part of that, taking away material of that second layer at particular places, placing there the concerned tubes and/or channels and then pour off the second layer (7).

11. Method according to claim 1, wherein for the third layer (9) a sound- absorbing material is chosen.

12. Concrete floor, manufactured according to the method according to one or more of preceding claims.