WO2019086791A1

WO2019086791A1 - Construction method comprising the production of at least one slab made of concrete and non-prestressed wood, and a slab made of concrete and wood

Info

Publication number: WO2019086791A1
Application number: PCT/FR2018/052675
Authority: WO
Inventors: Arnaud CHARLE; Thierry NIVIERE
Original assignee: A2C Materiaux
Priority date: 2017-10-30
Filing date: 2018-10-26
Publication date: 2019-05-09
Also published as: FR3072986A1; FR3072986B1; EP3704324A1; EP3704324C0; EP3704324B1

Abstract

The present invention relates to a construction method, comprising the production of at least one slab (1) according to the following steps: - casting a thin slab (2) of concrete; - laying metal stiffeners (3) in the thin slab (2) of freshly cast concrete; - cutting at least two blocks of wood (p1-p3); - placing the blocks of wood between the stiffeners (3) emerging from the thin slab (2) of freshly cast concrete and leaving a space between the adjacent blocks of wood (p1-p3); - casting concrete ribs (n1, n2) between the blocks of wood (p1-p3), by at least partly embedding the stiffeners (3); and - drying the non-prestressed slab (1) consisting of the thin slab (2) of concrete, stiffeners (3), blocks of wood (p1-p3) and concrete ribs (n1, n2).

Description

CONSTRUCTION PROCESS COMPRISING THE PRODUCTION OF AT LEAST ONE CONCRETE SLAB AND NON-PRECONTRATED WOOD, AND CONCRETE SLAB AND WOOD

TECHNICAL AREA

The present invention relates to the technical field of building construction, and more particularly to the reinforced concrete construction.

PRIOR ART

It is known from the state of the art several ways to treat a concrete floor. The two most common solutions are:

- cast in place, that is to say on a building site, using formwork,

- the use of pre-slabs manufactured generally in the factory, outside the building site.

The cast in place has the disadvantage of the time and the manpower necessary for its implementation. In particular, a long time is essential for the drying of the concrete before the construction of an upper floor can be started. The existing hollow core slabs have an unattractive appearance. In addition, these hollow slabs do not allow easy integration of reservations for water pipes, ventilation, electrical cables etc. As a result, the use of hollow core slabs is generally limited to industrial buildings or car parks. Thus, there is the need to adapt slabs to use for housing and offices.

Ecological requirements are becoming more and more important in the building. Thus, the emission of C0 ₂ during construction must be limited. However, the cement required for the manufacture of concrete remains an important source of C0 ₂ emissions. It is therefore conceivable that the reduction in the use of cement is desired. In addition the introduction of bio-sourced insulating panels between the concrete ribs allows a further reduction of the CO ² footprint of the finished floor.

DE 102004059590 discloses a method of constructing a ceiling, comprising hollow bodies for lightening the construction. The hollow bodies are an inverted U shape or a wavy form. The hollow bodies can be metal, plastic, wood, chipboard or corrugated board. The hollow bodies leave voids in the slab, which is not entirely satisfactory in terms of mechanical strength, and acoustic and thermal performance. When workers walk on the site, they may deform the hollow bodies, before their recovery by a compression slab.

GB1401439 discloses a method of building a slab, comprising lightweight blocks for lightening the construction. The blocks at the ends of the slab are provided with a height less than that of the blocks located between the ends. The blocks can be polystyrene, wood wool, metal or cardboard. Polystyrene is not entirely satisfactory in terms of mechanical strength and ecological footprint. The metal is not entirely satisfactory in terms of cost, ecological footprint, and acoustic and thermal performance. Wood wool and cardboard are not entirely satisfactory in terms of mechanical strength, acoustic and thermal performance.

SUMMARY OF THE INVENTION

One of the aims of the invention is therefore to propose an improved method of construction, the method comprising the production of at least one slab of concrete and wood. The slab resulting from the process must be aesthetic, resistant, easy to install, environmentally friendly to produce, and have good acoustic and thermal performance.

Another object of the invention is to facilitate the integration of reservations for conduits and cables, and thus allow the use of the method according to the invention in the construction of buildings, including housing.

For this purpose, the subject of the invention is a method of construction, comprising the production of at least one slab according to the following steps:

- casting of a concrete slab;

laying of metal stiffeners in the still fresh concrete slab;

cutting of at least two pieces of wood;

lay some loaves of wood between the stiffeners emerging from the still cool concrete slab and leaving a gap between the adjacent loaves of wood; pouring concrete ribs between the wood buns, drowning the stiffeners at least in part; and

drying of the non-prestressed slab made of concrete slab, stiffeners, wood loaves and concrete ribs.

The invention also relates to a concrete and wood slab, characterized in that it comprises:

a concrete slab;

metal stiffeners integrated into the concrete slab;

- wooden loaves placed between the stiffeners emerging from the concrete slab, with a space between the adjacent wooden loaves; and

concrete ribs poured between the wooden loaves, drowning the stiffeners at least in part. According to other advantageous features of the invention, taken separately or in combination:

- The method comprises, prior to the casting of the concrete slab, a step of identifying areas of interference between, on the one hand, the ribs, and on the other hand, reservations provided in the slab. The metal stiffeners associated with the ribs outside the interference zones are laid with a reference difference between them. The metal stiffeners associated with the ribs in the zones of interference are placed in offset with the reference difference, to avoid said interferences.

- The reference difference between the metal stiffeners is of the order of 60 cm, while the offset is of the order of 10 cm from one side or the other.

- The method comprises additional steps: laying of the slab consisting of the slab, stiffeners, wood loaves and ribs that integrate the stiffeners and are secured to the dallette; then pouring a slab of compression above the slab by covering the wooden loaves and the ribs.

- The wooden loaves have a density of between 80 and 200 kg / m3.

- The wooden loaves have a density of between 120 and 140 kg / m3.

- The pl-p3 wooden breads have a thermal conductivity of between 0.038 and 0.044 W / (mK).

- The wooden loaves are made of wood fibers.

- The wood loaves are cut from single-ply wood fiber insulation boards.

- During the casting step of the concrete ribs between the wooden loaves, the stiffeners are embedded only partially in the concrete and emerge at the top of the ribs. - The cutting of the wood loaves can be done by water jet or by any other system.

- The concrete slab has a thickness of 6 cm.

- The slab has a length of up to 7.5m.

- The slab has a width of up to 3.8m.

- The finished floor has a thickness of 23 centimeters for spans from 6m51 to

7m50.

- The finished floor has a thickness of 20 centimeters for spans up to 6m50. Thanks to the invention, the slab can support the weight of the concrete poured on site (compression slab), give to the complex of the floor (slab concrete, breads of wood, concrete of the compression slab (poured on site)) good acoustic and thermal performance, and have a very favorable balance sheet in terms of C02 emissions. Workers can walk on the slab on site, without the risk of deforming it, before the casting of the compression slab. The wooden loaves can support the weight of the workers without being deformed, which would not be the case with hollow elements or light materials. This facilitates the establishment of networks (electrical, fluids, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended figures, in which:

- Figure 1 is a sectional view of the slab obtained by the method according to the invention; Figure 2 is a schematic representation in perspective of the slab with the stiffeners, before the laying of the wood rolls;

Figure 3 is a layout plan having interfering zones between ribs and reservations, said interference can be avoided by the use of the slab according to the invention;

Figure 4 is a plane similar to Figure 3, but with the ribs displaced to avoid interference;

Fig. 5 is a layout plan showing an area in which a slab with the reference gap between ribs can be used;

- Figure 6 is a layout plan showing an area in which the offset of the ribs does not avoid reservations. For the sake of simplification, the same elements carry the same numerical references in the different figures. DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method of construction, comprising the production of at least one slab 1 of reinforced concrete and wood, called slab BB. As shown in Figures 1 and 2, the slab 1 is composed of a slab 2, metal stiffeners 3 embedded in the concrete, ribs ni and n2 protruding from the slab 2, and wood rolls pl p3 arranged between the ribs ni and n2. Once the slab 1 is placed on its supports, an upper layer of concrete, called compression slab (not shown), is poured on the slab 1.

The pl-p3 wood rolls have a density of between 80 and 200 kg / m 3, preferably between 120 and 140 kg / m 3. The pl-p3 wooden rolls have a thermal conductivity of preferably between 0.036 and 0.046 W / (m), preferably between 0.038 and 0.044 W / (mK). The pl-p3 wood buns are preferably made of wood fibers. Even more preferably, the pl-p3 wood buns are obtained from single-layer insulating panels, rigid or semi-rigid, made of wood fibers. The panels may have a thickness of between 3 and 22 cm, preferably equal to 9 or 12 cm. The panels have fire behavior corresponding to class E, according to EN 13501-1.

A major problem with existing hollow core slabs is their lack of adaptability. Indeed, they are difficult to use to build housing or offices whose plans are very diverse, and require to accept a large number of reservations for water pipes, gas, ventilation, as well as for electrical cables , telecommunication, etc.

According to the invention, the offset of the ribs makes it possible to adapt the slab 1 to the specific needs of each construction project. In order to implement the method according to the invention, a preliminary step consists in identifying on the layout plane areas where a (virtual) collision occurs between the ribs and the reservations.

Thus, three different types of zones can be identified.

In the first type of zone, there are no collisions (see Figure 5) between the ribs n8 to nl l and the reservations r4 to r7. Thus, a slab 1 with the reference gap of 60 cm between ribs n8 to ni 1 can be used.

The second type of zone, called interference zone ZI, has collisions (see Figure 3). A first interference zone ZI is identified between the rib ni and the reservation rl, and a second interference zone ZI between the rib n5 and the reservation r3. The displacement of the ribs by a maximum of 10 cm compared to the reference deviation makes it possible to escape the reservations (see Figure 4). Thus, a slab 1 with ribs ni and n5 offset from the reference gap can be implemented.

The third type of zone (see Figure 6) designates the conflict zones ZC, where the displacement of ribs up to 10 cm does not prevent collisions. This is the case of the collision between rib nl2 and reservation r8, the displacement of which would cause a collision with reservation r9. Thus, in this zone ZC, a floor must be cast in place, or be formed of conventional predalles, without ribs or integrated insulation.

The method of manufacturing the slab 1 according to the invention, described in detail below, comprises the following steps:

1) Pouring of a slab 2 of concrete. Preferably, slab 2 has a thickness of 6 cm.

Thanks to the invention, its length can reach 7.5 m, and its width can reach 3.8 m.

2) Laying metal stiffeners 3 in slab 2 of still fresh concrete, at positions that are based on reservations and ZI interference zones, as described above. The stiffeners comprise vertical elements 3a and horizontal elements 3b. The elements 3a protrude from the slab 2, while the elements 3b are fully integrated with the slab 2. The vertical elements 3 has stiffeners 3 are placed either with the reference difference between them (preferably 60 cm), with a deviation greater or less than the reference deviation, to avoid ZI interference zones.

3) Cutting the wooden breads pl p3, preferably by water jet, the right dimensions. Preferably, the cut p3 wood rolls may have a width of 48 cm, and a height of 9 or 12 cm. The length of the woodwinds pl p3 cut depends in particular on the length of the slab 1 to achieve.

4) Through openings are formed in the wood rolls pl p3 to serve, for example, cable passages. Of course, other conduits and pipes can be passed through these openings.

5) Laying wood buns pl p3 between the vertical elements 3a stiffeners 3 emerging from slab 2 still fresh concrete. Thus, the wood rolls pl to p3 are secured to the slab 2 by adhesion between the wood and the fresh concrete, then during the drying of the concrete.

6) casting the ribs ni and n2 between the wood rolls pl to p3, by embedding the vertical elements 3a of the stiffeners 3 in whole or in part.

7) Installation on site of each slab 1 consisting of slab 2, stiffeners 3, wood rolls pl to p3 and ribs ni and n2, which integrate the vertical elements 3a of the stiffeners 3 and are secured to slab 2.

8) Pouring a compression slab (not shown), preferably of a thickness of 5 cm, above each slab 1.

Of course, a floor may be composed of a plurality of adjacent slabs 1, and thus the casting of the compression slab may be performed simultaneously for several slabs 1.

Steps 1) to 6) are preferably performed off-site, for example in the factory, while steps 7) and 8) are performed on the job site.

The number of operations carried out on the site is minimized.

Alternatively, it may be envisaged to perform steps 1) and 2) in the factory, while steps 3) to 8) are performed on the job site.

The invention makes it possible to improve the C0 ₂ balance sheet of the slab 1. This improvement is permitted thanks to the lightening of the slab 1, which is no longer a solid slab. The pl-p3 breads reduce the use of primary materials by more than 35%, while retaining the original lift, according to the experiments that led to the invention.

By lightening the floors, it is possible to reduce also the size of the concrete structure made up of posts, beams, foundations, etc.

The pl-p3 wooden breads, consuming C0 ₂ throughout their lifetime, make it possible to further improve the C02 balance of slab 1, which, potentially, can be zero or even positive. The pl-p3 wooden breads also increase the thermal and acoustic insulation of slab 1.

Pl-p3 woodwool has good fire resistance compared to polystyrene, wood wool or cardboard. The pl-p3 wooden breads also have good moisture resistance properties, compared to wood wool or cardboard.

The use of slag is advantageously possible, to further improve the C0 ₂ balance. Preferably, electric pots can be integrated directly to the slab 2, being put in place before casting slab 2.

Because the reservations, passages and pots are already integrated in the slab 1, the construction method according to the invention is particularly fast and simple to implement, minimizing the necessary operations on the site.

Advantageously, the length of the slab 1 may be less than or equal to 7.5 m. Thus, slab 1 can be laid over a maximum span of 7.5 m.

The choice of a width of 3.8 m reduces the number of joints to be treated. Thus, the laying of the slabs 1, obtained by the process according to the invention, is simpler and faster than with the existing slabs.

At the time of laying the slab 1, there is no need to position stabilizing struts on the underside, bringing a saving of time, equipment and hardship.

Furthermore, the slabs 1 and the construction may be shaped differently from Figures 1 to 6 without departing from the scope of the invention. In addition, the technical characteristics of the various embodiments and variants mentioned above may be, in whole or in part, combined with one another. Thus, the slab 1 can be adapted in terms of cost, functionality and performance.

Claims

Construction method, comprising the production of at least one slab (1) according to the following steps:

pouring a slab (2) of concrete;

laying metal stiffeners (3) in the slab (2) of still fresh concrete;

cutting of at least two pieces of wood (pl-p3);

placing wooden loaves (pl-p3) between the stiffeners (3) emerging from the slab (2) of still fresh concrete and leaving a space between the adjacent wooden loaves (pl-p3);

pouring ribs (nl-n6) of concrete between the wooden loaves (pl-p3), by embedding the stiffeners (3) at least in part; and

drying of the non-prestressed slab (1) consisting of the slab (2) of concrete, stiffeners (3), wooden rolls (pl-p3) and ribs (nl-n6) of concrete.

Construction method according to claim 1, characterized in that it comprises prior to the casting of the slab (2) of concrete:

a step of identification of interference zones (ZI) between, on the one hand, the ribs (nl-nl6) and, on the other hand, reservations (rl-rl 1) provided in the slab

(i);

and in that :

the metal stiffeners (3) associated with the ribs (n2-n4, n8-nl1) outside the interference zones (ZI) are laid with a reference difference between them; and

the metal stiffeners (3) associated with the ribs (n1, n5) in the interference zones (ZI) are placed offset from the reference gap in order to avoid said interferences.

Construction method according to claim 2, characterized in that the reference distance between the metal stiffeners (3) is 60 cm, while the offset is 10 cm on one side or the other.

Construction method according to one of the preceding claims, characterized in that it comprises the following additional steps:

- laying of the slab (1) consisting of slab (2), stiffeners (3), wood rolls (pl-p3) and ribs (ni, n2) which incorporate the stiffeners (3) and are secured to the slab (2); and

pouring a compression slab above the slab (1) covering the wooden loaves (pl-p3) and the ribs (ni, n2).

5. Construction method according to any one of the preceding claims, characterized in that during the casting step of the ribs (ni, n2) of concrete between the wood loaves (pl-p3), the stiffeners (3) are drowned only partially in the concrete and emerge at the top of the veins (ni, n2).

6. Construction method according to any one of the preceding claims, characterized in that the cutting of the wood loaves (pl-p3) is performed by water jet.

7. Construction method according to any one of the preceding claims, characterized in that the slab (2) made of concrete has a thickness of 6 cm.

8. Construction method according to any one of the preceding claims, characterized in that the slab (1) has a length of up to 7,5m

9. Construction method according to any one of the preceding claims, characterized in that the slab (1) has a width of up to 3.8m.

10. Slab (1) made of concrete and wood, characterized in that it comprises:

- a slab (2) of concrete;

metal stiffeners (3) integrated with the slab (2) of concrete;

wooden loaves (pl-p3) arranged between the stiffeners (3) emerging from the slab

(2) concrete, with a space between the adjacent wooden loaves (pl-p3); and ribs (nl-n6) of concrete poured between the wooden loaves (pl-p3), by embedding the stiffeners (3) at least in part.