GREEN CONSTRUCTION ELEMENT AND METHOD FOR THE PRODUCTION THEREOF

Abstract

A green construction element forming a vertical surface of the construction, the element including a porous concrete element and a coating on at least one of the surfaces of the porous concrete, directly in contact with the surface, the coating, which is favourable to the development of plants, including a plant or a seed of the plant, and the porous concrete having a porosity of between 10% and 40% in the hardened state thereof, before application of the coating, so as to be able to render the vertical surface of the construction green.

Claims

1.-17. (canceled)

18. A green construction element, forming a vertical surface of the construction, said element comprising: a) a porous concrete element, and b) a coating on at least one of the surfaces of said porous concrete, directly in contact with said surface, said coating which is favourable to the development of plants, comprising a plant or a seed of said plant, the porous concrete having a porosity of between 10% and 40% in the hardened state thereof, before application of the coating, so as to be able to render said vertical surface of the construction green.

19. The element according to claim 18, wherein the porous concrete has a porosity of between 30% and 35% in the hardened state thereof, before application of the coating.

20. The element according to claim 18, wherein the element is made of porous self-supporting concrete.

21. The element according to claim 20, wherein a compressive strength of the porous concrete element after 28 days is at least 3 MPa.

22. The element according to claim 20, wherein the compressive strength of the porous concrete element after 28 days is between 3 MPa and 30 MPa.

23. The element according to claim 18, wherein the element is made of porous self-placing concrete.

24. The element according to claim 18, wherein the porous concrete comprises per cubic metre of fresh concrete: 300 kg to 400 kg of a hydraulic binder and 80 litres to 110 litres of water, the ratio between the weight of water and the weight of hydraulic binder being between 0.2 and 0.35; and 1050 kg to 2000 kg of aggregates of which the diameter is from 4 mm to 15 mm.

25. The element according to claim 24, wherein the porous concrete does not comprise aggregates of which the diameter is less than 4 mm.

26. The element according to claim 24, wherein the hydraulic binder comprises a cement based on Portland clinker as defined in the European standard EN 197-1 or a cement based on sulphoaluminate clinker, or a magnesia binder, or a calcium aluminate cement.

27. The element according to claim 24, wherein the hydraulic binder further comprises a mineral addition having a D90 less than 200 m, selected from pozzolanic materials, ground limestone, and mixtures thereof.

28. The element according to claim 27, wherein the pozzolanic material is selected from metakaolins, silica fume and mixtures thereof.

29. The element according to claim 24, wherein the porous concrete further comprises a superplastifier.

30. The element according to claim 29, wherein a dry content weight percentage of the superplastifier varies from 0.05% to 1.0% compared to the weight of hydraulic binder.

31. The element according to claim 24, wherein the porous concrete further comprises a viscosity modifying agent and/or a yield stress modifying agent.

32. The element according to claim 24, wherein the porous concrete comprises between 150 litres and 250 litres of a hydraulic binder grout and water per cubic metre of fresh concrete.

33. The element according to claim 18, wherein the coating comprises a nutritive support and optionally cement.

34. The element according to claim 18, further comprising a structural concrete layer.

35. The element according to claim 34, wherein the structural concrete layer is in direct contact with the non-green surface of the porous concrete element.

36. The element according to claim 18, integrating a water intake element.

37. A method for preparing an element of a green construction according to claim 18, comprising: preparing a porous concrete element, as defined in claim 18; then applying a seeded coating by floating or spraying.

Description

EXAMPLES

[0142] In these examples, the materials used are available from the following suppliers:
CEMI 52.5 N PM-ES-CP2-NF, LafargeHolcim, Teil plant Fine gravel 6/10, LafargeHolcim, St Bonnet site (France)
Superplastifier ADVA Flow 450, Grace Construction Products (abridged ADVA 450 in the tables)

Metakaolin Lavolle S.A.

[0143] Limestone filler Corrire de La Vallee Heureuse

Method for Preparing the Concrete:

[0144] The porous concrete according to the invention was produced with a Zyclos type mixer (50 litres). The entire operation was carried out at 20 C. The preparation method included the following steps:

[0145] Placing the aggregates in the bowl of the mixer;

[0146] At T=0 second: starting the mixing;

[0147] At T=30 seconds: adding the moistening water (3 to 10% of the weight of dry aggregates) then continuing to mix up to 90 seconds;

[0148] At T=90 seconds: stopping the mixing and leaving to stand for 4 minutes;

[0149] At T=5 minutes and 30 seconds: adding the hydraulic binder;

[0150] At T=6 minutes and 30 seconds: mixing for 1 minute;

[0151] At T=7 minutes and 30 seconds: adding the remainder of the makeup water over 30 seconds (while mixing); and

[0152] At T=8 minutes: mixing for 2 minutes.

Method of Measuring the Density of the Concrete:

[0153] Once the concrete has been prepared, it is placed in a recipient of known internal volume. The density is the ratio between the measured weight of concrete and the internal volume of the recipient.

[0154] Two examples of porous concrete according to the invention were produced from cement grouts having the formulations (F1) and (F2) given in the following table:

TABLE-US-00001 TABLE 1 F1 F2 Weight of the component in kg Component per cubic metre of fresh concrete Cement CEMI 52.5N 333.6 179.5 PM-ES-CP2-NF Aggregates 6-10 mm St Bonnet 1570.8 1570.9 Metakaolin 82.5 Limestone filler 41.2 ADVA 450 3.3 3.9 Viscosity modifying agent 0.011 Water 90.0 91.0

[0155] The volume of cement grout was 199 litres (F1) and 202 litres (F2) per cubic metre of fresh concrete.

[0156] The binder grout was produced by mixing the cement, if need be the mineral addition, the superplastifier and water.

[0157] The spread of the hydraulic binder grout was measured according to the method described above. The results are given in the following table:

TABLE-US-00002 TABLE 2 F1 F2 Spread of the binder grout (mm) 310 350

[0158] The porous concretes were produced by mixing the constituents in a mixer and cylindrical test specimens of 11 cm diameter and 22 cm height were produced. The free surface of the porous concrete was leveled off with a straight edge. The cylindrical test specimens were conserved in conditions normalised to test their compressive strength after 7 days then after 28 days.

[0159] A measurement of the compressive strength of the concrete was carried out as described above. The test specimen was removed from the mould after 3 days. The porosity of the concrete in the hardened state was measured as has been described above.

[0160] B1: concrete obtained with the formulation F1; B2: concrete obtained with the formulation F2 The results are grouped together in the following table:

TABLE-US-00003 TABLE 3 B1 B2 Compressive strength after 7 days (MPa) 9.3 6.3 Compressive strength after 28 days (MPa) 10.2 9.9 Porosity (%) 32 32 Density (28 days) 1.7 1.7

[0161] A vertical wall 90 cm high, 40 cm wide and 15 cm thick was poured according to normal construction methods with the concrete composition B1. This composition is validated for the application of this invention because the porous wall is: [0162] of homogenous appearance, [0163] permeable (test carried out by flow of water whilst the wall was in horizontal position), [0164] without apparent cavities, and [0165] without apparent compaction defects.
On elements made of porous concrete B1 and B2, of dimensions 25 cm25 cm10 cm, a seeded coating comprising or not cement is applied by floating or spraying according to the information given in the following tables:

TABLE-US-00004 TABLE 4 Composition of the coating E1 E2 Earth 1500 mL 1500 mL Compost 1500 mL 1500 mL Cement 450 mL 0 mL Water 1250 mL 1250 mL

TABLE-US-00005 TABLE 5 Types of seeds and mixture proportions Mixture 1 Mixture 2 Seeds (g/m.sup.3 of concrete) (g/m.sup.3 of concrete) Ruta graveolus 198 396 Aurinia saxatilis 85 170 Cymbalaria muralis 21 42 Sedum acre 4 8
The 8 samples are stored and are subjected to the same conditions of light, watering and other environmental conditions. Good germination of all the seeds on all the samples is observed.