Building Materials

Abstract

The present invention relates to a building material comprising ground algae or aquatic plant remains and a binder of plant origin, characterized in that it contains an aqueous solution of an organic acid, the use of which improves the mechanical properties of the material and on the other hand acts as an antibacterial agent. The building material of the present invention can be used for the manufacture of prefabricated components for modular construction and as a biocement and fastener for sealing joints.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention relates to a new building material technical field, more particularly to a building material having heat insulation, sound insulation and fire retardancy, which comprises crushed algae or aquatic plant carcasses, a vegetable binder and an organic acid aqueous solution.

[0002] [Background technology] Sustainable building materials are those that are recycled or can be recovered or recycled and do not harm the environment. These materials must be energy efficient, have a long service life and possess properties that make them suitable for a variety of uses in construction. Materials used in construction must have high mechanical resistance and low density as well as fire resistance, sound insulation and thermal insulation properties.

[0003] In general, seaweed has very interesting construction properties, since it can be used as an insulating material without complex industrial processes and even without the use of chemical products.

[0004] The Fraunhofer Institute (Germany) has carried out several studies on cleaning (removing debris such as sand and stones) and disintegrating the remains of Posidonia seaweed to form fibers for the manufacture of building panels. Experiments have shown that these fibers can store 20% more energy than wood and are very effective as natural thermal and acoustic insulation materials. However, to obtain dimensional stability of materials based on this type of algae, binders and additives must be added.

[0005] EP1944423A2 describes the use of Posidonia oceanica fibres as insulating materials in building products together with suitable inorganic and organic binders such as gypsum (calcium sulphate), cement, aluminium oxide / silicon dioxide, lime (calcium carbonate), soluble glass, phosphate binders, synthetic resin binders, etc. However, the document does not elaborate on the mechanical properties of the product and binders that are not very compatible with the environmental objective of reusing algae are used.

[0006] ES2538576A1 describes a method for producing panels made from 60-80% residual fibers of Posidonia oceanica, 20-40% thermoplastic fibers (specifically polylactic acid) and 0-40% natural fibers (specifically hemp, sisal, flax and cotton fibers) by hot pressing. However, the production method for such panels requires high temperatures and pressures, which makes the method expensive, as it uses a large amount of resources.

[0007] EP 2840196 A1 describes a method for producing thermoacoustic insulating boards containing a mixture of Posidonia and diluted vegetable starch, but the document does not provide any detailed description of the mechanical properties of the resulting product, and the manufacturing process is lengthy, since it requires three months for the seaweed to mature and at least two days for the moulds.

[0008] There is therefore a need to obtain building materials that are sustainable, utilize residues such as Posidonia algae, do not contain toxic or environmentally harmful compounds in their formulations, are easy to obtain, are not resource-intensive and have acceptable or improved properties for use in construction.

[0009] The present invention solves a problem in the art by providing a building material that has improved mechanical properties and reduces the manufacturing time of some products, such as insulation panels made from this material, to one day. The building material of the invention has a lower density than cement, but exhibits good mechanical properties and can therefore be used as a cement, more specifically as a biocement.

[0010] An additional benefit is that using this material as a cement substitute can reduce energy consumption in cement production.

[0011] The solution found by the inventors is a building material with good thermal, sound and fire-retardant properties, which contains crushed aquatic plant remains, a plant-derived binder and an aqueous solution of organic acid. The acid donates protons and the water acts as a pH adjuster.

[0012] The use of aqueous organic acids improves the material's mechanical properties while acting as antibacterial agents. The material therefore contains no toxic substances or petroleum derivatives that could produce dangerous leachates. This makes it an ideal material for realizing a circular and sustainable economy in the building sector.

[0013] In a first aspect, the present invention relates to a building material comprising ground algae or aquatic plant remains and a binder of plant origin, characterized in that the building material contains an aqueous solution of an organic acid.

[0014] The organic acid solution can be generated from lactic acid, acetic acid, fumaric acid, glycolic acid, citric acid, malic acid or formic acid. In a preferred embodiment, the acid is acetic acid. As a source of acetic acid, glacial acetic acid or vinegar, diluted to a pH of 4 to 5.5, can be used. Lowering the pH of the mixture can reduce the microbial load, prevent algae decomposition and prevent the generation of odors.

[0015] The algae or aquatic plants are collected from the shore where they die and are later crushed. In a preferred embodiment, the algae or aquatic plants are selected from Posidonia Oceanica, Sargassum or Rugulopterix okamurae.

[0016] In a preferred embodiment, the size of the crushed algae or aquatic plant carcasses is 1 to 5 mm. If the size is smaller than 1 mm, the compressive strength decreases, and if the size is larger than 5 mm, bending occurs. The plant-derived binder comprises a polysaccharide, preferably a starch, more preferably corn, cassava or wheat starch. In certain embodiments, the building materials of the present invention include a reinforcing agent, a water repellent, a plasticizer, a fire retardant, or a mixture thereof.

[0017] In a preferred embodiment, the flame retardant is potassium bicarbonate. In a preferred embodiment, the reinforcing agent is calcium carbonate. In a preferred embodiment, the plasticizer is polycaprolactone, which also improves flexural properties. In another particular embodiment, the building material of the present invention comprises dried ground Posidonia oceanica having a size of 1-5 mm, wheat starch, an aqueous solution of acetic acid having a pH of 4-5.5, potassium bicarbonate, calcium carbonate and polycaprolactone.

[0018] In another particular embodiment, the building material of the present invention comprises 16-18% dried ground Posidonia oceanica ground to a size of 1-5 mm, 10-20% starch, 1-10% aqueous acetic acid solution at pH 4.6, 2-20% potassium bicarbonate, 8-25% calcium carbonate, 3-5% polycaprolactone and 35-60% water. All the percentages are expressed as weight / weight.

[0019] In certain embodiments, the building materials may include: Sludge obtained from sewage sludge, which reduces density, improves insulation and increases compressive strength; Ash to improve compressive strength, Sawdust obtained from plant biomass; Cork for added sound insulation, and / or A foaming agent that reduces density. The building material of the present invention has a compressive strength of more than 10 MPa, a flexural strength of more than 3.0 MPa, and a tensile strength of more than 5.0 MPa.

[0020] The properties obtained for the material of the invention are as follows: -Density: 200kg / m 3 ~1.000kg / m 3 , depending on the amount of calcium carbonate added and compression. -Fire stability: Flame retardant A1 (non-flammable) ~ s1 (low smoke opacity) ~ d0 (does not produce flaming droplets or particles). -Water behavior: Repels water. -Insulation: Thermal conductivity is lower than 0.035W / m*K at 15mm thickness. - Sound insulation: Measurements taken on a 4cm thick wall showed that in the frequency spectrum of 500-10,000Hz, internal noise was measured at 62-71dB and external noise was measured at 114-117dB. The building material according to the invention is biodegradable, while retaining its mechanical properties for at least 50 years.

[0021] In another aspect, the present invention relates to a method for producing a building material as defined above, comprising the following steps: a) The process of sorting, sieving and crushing algae and dried aquatic plants. b) mixing the pulverized algae or aquatic plants with a plant-derived binder and an aqueous organic acid solution.

[0022] In certain embodiments, the method of the present invention further comprises the subsequent step of compressing and drying the mixture from step b). In a preferred embodiment, in the method of the present invention, the organic acid aqueous solution is an acetic acid aqueous solution, the algae or aquatic plant is selected from Posidonia Oceanica, sargassum or Rugulopterix okamurae having a size of 1-3 mm, and the vegetable binder is starch.

[0023] In another aspect, the present invention relates to the use of a building material as defined above for manufacturing prefabricated components for modular buildings.

[0024] In the context of the present invention, a prefabricated component is understood as a material manufactured at a location other than the location corresponding to its application or use. This prefabricated component can adopt different means and forms so that its assembly can be carried out at the location of the application or use. For example, this prefabricated component can be a board or a panel for an interior partition, a false ceiling, a partition, etc.

[0025] The building material of the present invention can be used to manufacture sandwich panels. In a particular embodiment, the building material of the present invention comprises a cardboard layer / board covering at least one surface of the panel. Preferably, the building material of the present invention comprises a cardboard layer / board covering at least two surfaces or faces of the panel, forming a sandwich type panel.

[0026] In another aspect, the present invention relates to the use of a building material as defined above as a biocement for sealing joints and as a fixing agent. The material of the invention allows the use of typical cement accelerators, such as sodium acetate, sodium bicarbonate, sodium carbonate or mixtures thereof, the addition of which makes it possible to seal the material against water penetration by accelerating the hardening process.

[0027] In the context of the present invention, "biocement" is understood to be a cement of natural origin that has cementitious properties. [Description of the embodiment] [Example 1. Method for producing the material of the present invention]

[0028] First, 1-5 mm dead leaves of Posidonia Oceanica were dried, sorted, sieved, and crushed. Then, the leaves were mixed with wheat starch and acetic acid solution (wine vinegar diluted with water, pH 4.6). Finally, the mixture was placed in an airtight container to adjust the humidity. The resulting material can be used as a biocement. Example 2. Properties of the material of the present invention

[0029] Different samples of the material of the present invention were prepared in the same manner as described in Example 1. The content of the components in each sample is detailed in Table 1. [Table 1]

[0030] Density, compressive strength, and flexural strength measurements were performed on each sample, and the values ​​obtained are shown in Table 2. [Table 2] It can be seen that the higher the density of the material, the higher the compressive strength. Example 3. Building material of the present invention containing cork, sludge, and soap

[0031] Cork, sludge, and soap were added to Sample 3 of Example 2. The content of each component in each sample is detailed in Table 3. [Table 3] Relative to the reference sample 3, sample 5 exhibited higher sound insulation, sample 6 exhibited higher mechanical resistance and sample 8 exhibited lower density.

[0032] [Example 4. Manufacturing method of prefabricated insulation panels] The material obtained in Example 1 was placed in a mold and pressed at 20 KN to obtain an insulating panel, which was then dried in a convection microwave oven and finally demolded and palletized. [Example 5. Manufacturing of sandwich panels]

[0033] The panel obtained in Example 4 was used as a partition by covering both sides with cardboard. A hole was drilled in the panel and a weight of 30 kg was placed on it. As a result, the panel did not deteriorate and showed great resistance. [Example 6. Production of biocement from panels]

[0034] The panels described in Example 4 were crushed and stored in sealed bags indicating the amount of water required to produce the biocement. The resulting biocement had the same properties and composition as the biocement obtained in Example 1, the properties of which are shown in Example 2. The material of the present invention can therefore be considered reversible.

Claims

1. A building material comprising ground algae or aquatic plant remains and a plant-derived binder, the building material being characterized in that it contains an aqueous solution of an organic acid.

2. 2. The building material according to claim 1, wherein the organic acid solution is an aqueous solution of acetic acid.

3. 3. A building material according to claim 1 or 2, characterized in that the algae or aquatic plants are selected from Posidonia Oceanica, Sargassum or Rugulopterix okamurae.

4. 4. A building material according to claim 1, wherein the size of the crushed pieces of dead algae or aquatic plants is 1 to 3 mm.

5. 5. A building material according to claim 1, characterized in that the binder of vegetable origin is a starch.

6. 6. A building material according to any one of claims 1 to 5, characterised in that it comprises a reinforcing agent, a water repellent, a plasticiser, a flame retardant or a mixture thereof.

7. Dried and ground Posidonia oceanica having a size of 1-3 mm; Wheat starch; An aqueous solution of acetic acid having a pH of 4 to 5.5; Potassium bicarbonate; Calcium carbonate; and Polycaprolactone; 7. A building material according to claim 1, comprising:

8. 16-18% by weight of dried ground Posidonia oceanica having a size of 1-5 mm; 10-20% by weight of starch; 1-10% by weight of an aqueous solution of acetic acid having a pH of 4.6; 2-20% by weight of potassium bicarbonate; 8-25% by weight of calcium carbonate; 3-5% by weight of polycaprolactone; and 35-60% water 7. A building material according to claim 1, comprising:

9. 9. The building material according to any one of claims 1 to 8, further comprising cork, sludge, ash, sawdust, a foaming agent or a mixture thereof.

10. a) drying, shifting, sieving and crushing the remains of algae or aquatic plants; and b) mixing the ground algae or aquatic plant with a plant-derived binder and an aqueous organic acid solution; A method for producing a building material according to any one of claims 1 to 9, comprising:

11. The process of claim 10 further comprising the subsequent steps of compressing and drying the mixture of step b).

12. The method according to claim 10 or 11, characterized in that the organic acid aqueous solution is an aqueous solution of acetic acid, the crushed algae or aquatic plant carcasses are selected from Posidonia oceanica, Sargassum or Amidia fasciata having a size of 1 to 5 mm, and the plant-derived binder is starch.

13. A building material obtainable by the method according to claim 11, characterized in that said material has a mechanical resistance to compression of more than 10 MPa and a resistance to bending of more than 3 MPa.

14. 10. Use of a building material according to any of claims 1 to 9 for manufacturing prefabricated components for modular buildings.

15. 10. Use of a building material according to any of claims 1 to 9 as a biocement and fixing material for sealing joints.

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