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    • 专利摘要:
    Method and composition for the manufacture of esparto reinforced building blocks. The present invention relates to a composition for the manufacture of blocks of compressed earth stabilized reinforced with esparto (betce) comprising: earth, in a proportion of 70-80% of the total dry weight of the composition, a binder formed by the combination of slaked lime (ca (oh)2), in a proportion of 2-3% of the total dry weight of the composition and portland cement, in a proportion of 12-15% of the total dry weight of the composition, and esparto fiber, in a proportion of 12-13% of the total dry weight of the composition. Also, the present invention contemplates esparto-reinforced building blocks comprising the composition of the invention, as well as the method for the manufacture thereof. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2598603A1
    申请号:ES201631685
    申请日:2016-12-27
    公开日:2017-01-27
    发明作者:Ignacio CAÑAS GUERRERO；Fernando ARREDONDO RUIZ
    申请人:Universidad Politecnica de Madrid；
    IPC主号:
    专利说明:

    DESCRIPTIONMethod and composition for the manufacture of esparto reinforced building blocks  5
    Object of the invention

    The present invention relates to materials for the manufacture of compressed earth blocks (BTC) intended for construction. In particular, the present invention contemplates compositions for the production of Stabilized Blocks of Low-density Compressed Fiber-reinforced Earth (BETCE), as well as the process for producing said blocks. These low-cost blocks have insulating properties and are compatible with the environment. Its main scope is in the construction sector, particularly in the formation of interior partition walls or restoration of houses that are not energy efficient. They can also be used for other applications, such as exterior cladding.

    Background of the invention
     twenty
    The huge impact of the construction sector on the environment makes it necessary to develop construction techniques with minimal environmental impact, capable of offering a more natural and healthy environment for people (Jorge Seisdedos; Rafael López. Unit of production of land blocks Compressed-BTC. V Earth Congress in Cuenca de Campos, Valladolid, 2008). 25

    The use of Compressed Earth Blocks (BTC) in the building is one of the most appropriate current construction systems in ecological terms due to the minimum environmental impact of its Global Life Cycle. The material is basically composed of excavation soil (with an adequate percentage of clay) and a reduced volume (6-8%) of stabilizer (cement or natural hydraulic lime) (Jorge Seisdedos; Rafael López (2008)).
    Compressed earth blocks may or may not be stabilized with cement or lime. Therefore, they are currently preferred to call Compressed Stabilized Earth Blocks (BTEC). This stabilization of the ground has allowed to build taller, with thinner walls, with greater resistance to both compression and water. With the stabilization 35 of the cement-based soil, the blocks must be cured for four weeks after manufacture. After this, they can be dried freely and used as common bricks with a stabilized cement mortar for floors.

    Although the earth is not a standardized construction material, it has a series of 40 advantages compared to other industrial construction materials, since it is able to regulate the environmental humidity in greater quantity and speed than in the other construction materials. Regulates indoor weather conditions as well as other materials
    They have high density. It does not produce environmental pollution and saves energy, it can also be reused.

    In December 2008, the UNE 41410 Standard (AENOR: Compressed earth blocks for walls and partitions. Definitions, specifications and test methods. UNE 41410, Madrid, 2008) that allows the use of cement / lime / plaster was published in Spain. as stabilizers or additives in a percentage of dry mass less than or equal to 15%, likewise the clay content of the soil itself must be greater than 10%.

    The present invention therefore has its origin in the growing need to find 10 construction materials with less environmental impact and that are increasingly independent of fossil fuel sources, thus reducing their use to maintain environmental humidity conditions. and optimum temperature inside buildings.
     fifteen
    In this regard, there are several studies that analyze different aspects of thermal insulation in buildings. In the OTI document, J.E., KINUTHIA, J.M. and BAI, J., 2010. Design thermal values for unfired clay bricks. Materials & Design, vol. 31, no. 1, pp. 104-112. DOI 10.1016 / j.matdes.2009.07.011, the thermal properties of raw earth blocks are measured and compared with the thermal properties of cooked bricks. 20 The results were used before the test to predict the thermal design values of raw earth bricks with varying density and moisture content. The results show that the raw earth blocks were able to meet the thermal design requirements of the cooked bricks, suggesting that the raw earth blocks can be used for the construction of low-to-medium-cost housing and structures efficient masonry.

    The U coefficient, or U value, is the overall heat transfer coefficient that describes the way in which a building element conducts heat, or the heat transfer rate (in watts), through a square meter of a structure divided by the temperature difference across the structure. In tests carried out in the United Kingdom on earth envelopes, it was shown that “the U value” of a version of these materials exceeded 100% of the requirements of the construction code of that country. Likewise, it was verified that the earth materials can be used in construction and comply with the thermal requirements of the building code of Great Britain 35 (GOODHEW, S. and GRIFFITHS, R., 2005. Sustainable earth walls to meet the building regulations Energy and Buildings, vol. 37, no. 5, pp. 451–459. DOI 10.1016 / j. enbuild. 2004.08.005).

    WO 2003004435 patents, on hemp mortars or concrete mixtures, WO 40 2002027110 A1, on a thermal and acoustic insulator whose material is hemp fibers, US 20140014005, where the creation of PAPERCRETE blocks are made with the mixture of sand, Portland cement and cellulose material such as fiber, and subsequent US 20150104621 A1 and US 20110094421 A1, refer to the creation of BTC type building materials with the addition of plant fibers and to the improvement of the 45
    insulating properties derived from the use of these fibers.
    On the other hand, there is a need to create insulating materials for construction at a lower economic cost (OTI, JE, KINUTHIA, JM, BAI J., 2008. Energy-saving and C02 emission: how unfired claybased building materials development in the UK can contribute.In: Proceedings of the 1st international conference on industrialized, integrated, intelligent 5 construction.Loughborough, UK, 14-16 May; 2008).
    Given these needs, the authors of the present invention, after an important experimentation work, have created a new material to produce a stabilized block of compressed earth of low density reinforced with esparto fibers (BETCE) that presents a thermal conductivity lower than materials used so far in the prior art, thus presenting a better thermal insulation.

    Likewise, they have developed a procedure to obtain this type of materials, which includes a series of processes that reduce production costs, thus avoiding the cooking process, with high energy expenditure and its consequent environmental impact. fifteen

    The new material is formed by soil, lime, Portland cement and esparto fibers in certain proportions that, after their mixing, compaction, dehydration and curing process, give rise to a new construction material with improved insulating properties, low cost and compatible with the environment. twenty

    Description of the invention
    Based on the growing need, in the state of the art, to find new construction materials that have minimal environmental impact and improved insulating properties, the authors of the present invention have developed a new material, alternative to those already existing, of Low environmental impact, which improves these properties.

    Thus, a first main aspect of the invention contemplates a new composition for the manufacture of Stabilized Compressed Earth Blocks of low density and reinforced with Esparto fiber (BETCE) (hereinafter composition of the invention) comprising:
    a) Land in a proportion of 70-80% of the total dry weight of the composition,
    b) Binder formed by the combination of slaked lime (Ca (OH) 2), in a proportion of 2-3% of the total dry weight of the composition, and Portland cement, in a proportion of 12-15% of the dry weight total composition, and
    c) Esparto fiber in a 12-13% proportion of the total dry weight of the composition.
    In the present invention, the term "earth" or "soil" refers to the combination of different soil granulometries (gravel, sand, silt and clay) that does not contain organic matter or soil particles larger than 5 mm. 40

    As mentioned above, the use of vegetable fibers of esparto in the
    The composition of the invention allows the insulating properties to be improved compared to other building blocks or blocks of compressed stabilized earth (BTEC) that use other vegetable fibers such as jute, hemp or sisal.

    The esparto, also known as stipa tenacísima, is a natural fiber that comes from 5 wild plants of the group of grasses, which grow in dry areas. The leaves of the esparto are filiform, sclerophyllo and very tenuous, between 30 and 100 cm in length and 1 to 4 mm in width. The esparto panicle is somewhat dense, 25 to 35 cm in soil occupation. It lives in the steppe soils, characterized by the absolute lack of mulch, large proportion of lime and magnesium, sodium or potassium salts (especially sodium chloride is not lacking) and low humidity. They consist of cellulose, grease, waxes, "pectic materials", water and ashes.

    It has many uses, both domestic and industrial. Its main characteristic within the home is energy saving due to its insulating properties, if its location is well chosen. It is used to assemble the plaster, providing it with a high tensile strength, especially in the formation of plasterboard fasteners reinforced with fiberglass for the realization of false ceilings.

    Its main advantages for construction are its resistance to rotting by water, its high tensile strength and its protection against moisture, which allows it to develop a good response in outdoor environments. It also presents another series of properties such as resistance to fire, insects, and mold, so that esparto is a widely used construction and plumbing material.
    The compacted esparto allows the construction with organic forms (curves) and is easily adaptable. It is a vegetable fiber and, as such, it is biodegradable and its thermal conductivity is 17 times lower than that of conventional brick (RAMÍREZ, DA, 2006. Study of the transpiration of esparto. University of Alicante. BRUMMER, M. Housing with hemp structure EcoHabitar: quarterly magazine of bioconstruction, permaculture and sustainable life.Ecohabitar Visiones Sostenibles, SA Number 8. Olba, 30 Teruel, 2006. Page 14-17, GIL, M. Casas de Cannabis, La Vanguardia, Javier Godó. June 2008, Barcelona).

    Thermal insulation, ductility and tensile strength can be improved by adding natural fibers to the soil or soil mixture. In preferred embodiments of the composition of the invention, the use of esparto fibers provides thermal conductivity values between 0.137 W / m · K and 0.164 W / m · K.

    In a preferred embodiment of the composition of the invention, the size of the esparto fibers is between 10 and 30 mm, since greater lengths do not allow the correct kneading of the mixture.

    The percentages used of each component in the composition of the invention should allow the manufacture of the blocks to be practical in the field or at the site where
    They are going to make these blocks. The tolerances are wide for variations in the mixtures, and, as long as they do not exceed these tolerances, they allow consistent and good quality blocks to be produced.

    As for the binder used in the composition of the present invention, the combination of slaked lime (Ca (OH) 2) is used as a stabilizer, in a concentration of 2-3% of the total weight of the dry weight of the composition, whose contact with the earth will lead to an exchange of ions that result in the agglomeration of the particles, thus preventing water penetration. Likewise, Portland cement will be applied in a concentration of 12-15% of the total dry weight of the composition. Cement acts as a stabilizer against water in soils with low clay content, interrupting the binding forces of clay.

    In a second main embodiment of the invention a block of stabilized compressed reinforced esparto (BETCE) stabilized land comprising the composition of the present invention is contemplated. The materials that make up the blocks are completely natural, non-toxic, and do not emit gases.

    The blocks of the invention can be manufactured to a predictable size and have true flat sides and 90 degree angular edges. This makes the design and calculation of costs 20 easier. It also provides the option to make the exteriors look like conventional construction houses.

    A third main aspect of the present invention contemplates a method for the manufacture of Stabilized Compressed Earth Blocks of low density with Esparto 25 as natural fiber (BETCE) (hereinafter method of the invention) comprising the following steps:
    i) Mix the following components:
    - Earth, in a proportion of 70-80% of the total dry weight of the composition, 30
    - Binder, formed by the combination of slaked lime, in a proportion of 2-3%, and Portland cement in a proportion of 12-15% of the total dry weight of the composition, and
    - esparto fiber in a proportion of 12-13%, of the total dry weight of the composition, 35
    ii) Add to the mixture obtained in i) kneading water in a percentage between 45 and 55% of the total dry weight of the mixture and knead for a time less than or equal to 5 minutes,
    iii) Compact the mixture obtained in ii) to obtain a wet block, hereinafter referred to as Stabilized Compressed Earth Block 40 of low density and reinforced with Esparto fibers (BETCE),
    iv) Dehydrate or dry the wet BETCE block obtained in iii), and
    v) Cure the dehydrated block obtained in iv) for 7-9 days.
    The compaction or pressing stage, as well as the addition of stabilizers such as lime and cement, makes it possible to dispense with the cooking process in the method of the present invention, since the block is left with sufficient cohesion and physical characteristics that allow it to do the job. of a brick or building block. In this way, the energy costs inherent in the burning of fuels are saved. Also the environmental costs 5 are significantly reduced as there is practically no carbon contribution to the atmosphere, especially if the blocks are manufactured in the place where they are going to be built (transport is avoided).

    For the selection of soil (soil), the clay obtained from a lower layer of soil must be dried by the incidence of sun and wind. Subsequently it is sprayed, causing an increase in humidity and mixed with sand in varying proportions depending on the clay in the loam.

    Before preparing the mixture, the soil is extracted and hovered (in a mechanical sieve). 15 Subsequently, the proportions of the different components of the extracted earth are measured.

    The soil to manufacture compressed earth blocks, granulometrically speaking, should preferably be composed of about: 15% gravel + 50% sand + 15% 20 silt and 20% clay. If the soil collected from the local source does not have these proportions, it is convenient to add more of the missing component until the correct proportion is reached. It is important that the soil sample does not contain rocks or organic material, as it is in the most superficial soil layer.
    In the present invention, 70-80% of soil has been selected, for subsequent mixing with the binder and the esparto fiber.

    Cement constitutes the stabilizing medium. Cement aggregate improves soil conditions with respect to the action of agents such as moisture, giving it stability and resistance characteristics. 30

    The dosage of the binder is carried out in units of weight in relation to the amount of soil used for the mixture. This depends, to a large extent, on the compaction system adopted (GATANI, MP, 2000. Floor-cement bricks: traditional masonry based on sustainable material. Construction reports, vol. 51, no. 466, 35 pp. 35–47. DOI 10.3989 / ic.2000.v51.i466.713):
    -A less compaction, greater presence of cement.
    -A greater compaction, less presence of cement.
    In the present invention a mixture of slaked lime is used in 2-3% of the total dry weight of the mixture and Portland cement in 12-15% of the total dry weight of the mixture. 40

    Preferably, the esparto fibers used in the composition are about 10 to 30 mm in size. A manual cut is made and added to the mixture in a concentration of 12-13% for the manufacture of the BETCE.

    Before carrying out step i) of the method of the present invention, it is convenient to ensure that the soil is well ground and has no lumps. Once this check is done, all dry components (soil, lime, portland cement and esparto fibers) are mixed thoroughly for a time equal to or less than 5 minutes. Only then is water (ii) added until a moisture level is obtained that allows a ball to be made in the hands, so that, after handling the ball of the mixture, the hands should not be wet. The manipulated ball, when dropped from a height of 1.2 meters, must be broken into large pieces. At that time you have a good mix to make blocks in a press.

    The kneading of the materials with the water is carried out either in a mechanical stirrer 15 or with a shovel and / or hoe until a homogeneous mass is obtained.
    Subsequently, in the stage of compaction or pressing (iii), the mass thus obtained is put into the molds of the press, either mechanical or manual, where pressure is applied to it to give shape and strength to the block, obtaining a wet BETCE block.
     twenty
    Once pressed, the wet blocks are dried by the dehydration (iv) and curing (v) stages. First they settle on the ground, in the shade, so that they do not dry too quickly in the sun because they would break, preferably at room temperature. If necessary, the blocks are placed on a plastic so that they do not absorb soil moisture in case it is excessive. They are left in the shade 25 until they are dried by the effect of the humidity differential between the block and the relative humidity of the atmosphere. Depending on the relative humidity present on the site and at the time of the year in which they are manufactured, it will take more or less to dry. However, since they are made with low humidity, the drying time is much shorter than that of adobe. 30

    This drying method considerably reduces the incorporated energy of the resulting block because it does not carry cooking.

    The curing stage (v) is carried out for 7 to 9 days, since it should not dry too quickly. The blocks must be protected from direct sun and wind and, in some cases, a spray can be maintained with water from the blocks during the entire curing time, being able to add between 20 and 40 g of NaOH per liter of water.

    The soil blocks stabilized with cement reach maximum resistance at 28 40 days, as does concrete.

    The BTECE blocks obtained are used for the production of a sustainable building material with a high degree of insulation. Its use provides clear advantages over
    Conventional construction materials due to their capacity as thermal (and acoustic) insulator, their low cost, for being made with renewable / sustainable materials, and for being environmentally friendly, as well as not being toxic.

    After performing different tests in the production of BETC with esparto fiber, it is verified that the introduction of fiber effectively reduces the thermal conductivity of the blocks, obtaining relatively low values compared to the raw earth blocks without fiber (0.9-1.2 W / m · K), considerably improving its insulating properties.
     10
    The mechanical strength of the BETCE allows the blocks to be used in all types of buildings. As a constructive element, it allows its use in the construction and formation of dividing walls in the interior or restoration of houses that are not energy efficient. They can also be used for other applications such as exterior cladding. fifteen
    Example
    Thermal conductivity tests were carried out on three stabilized blocks of compressed earth reinforced with Esparto fiber (BETCE) prepared, according to the method of the present invention, from a composition formed by 12% by weight of esparto fiber, 12 % by weight of Portland cement, 2% by weight of lime and 74% by weight of soil. twenty

    The tests carried out indicated that the use of esparto fiber as an insulator provides a great decrease in thermal conductivity. The following table (table 1) shows the data obtained from its insulating properties in W / K · m, whose values range between 0.137 W / K · m and 0.194 W / K · m: 25

    Table 1. Thermal conductivity (W / K · m) of building blocks reinforced with esparto.
     Sample I Sample II Sample III
     Esparto  0.145 (0.002) 0.185 (0.003) 0.131 (0.002)
     0.147 (0.002)  0.178 (0.002) 0.136 (0.002)
     0.199 (0.002)  0.220 (0.004) 0.145 (0.003)
     Half  0.164 0.194 0.137

    Likewise, comparative tests were carried out with compositions of the state of the art using another type of vegetable fibers (coconut fiber and a commercial hemp block called Cannabric). As can be seen in Table 2, the lowest thermal conductivity is provided by the esparto.
    Table 2. Thermal conductivity (W / K · m) of three types of building blocks reinforced with vegetable fibers (coconut fiber, esparto and hemp).
     Thermal conductivity
     Coconut fiber  Sample I Sample II Sample III
     0.214 (0.008)  0.214 (0.005) 0.212 (0.005)
     0.185 (0.002)  0.196 (0.001) 0.190 (0.001)
     0.171 (0.002)  0.224 (0.003) 0.202 (0.002)
     Half  0.190 0.211 0.201
     Esparto  0.145 (0.002) 0.185 (0.003) 0.131 (0.002)
     0.147 (0.002)  0.178 (0.002) 0.136 (0.002)
     0.199 (0.002)  0.220 (0.004) 0.145 (0.003)
     Half  0.164 0.194 0.137
     Hemp (Cannabric)  0.251 (0.006)
     0.240 (0.003)
     0.247 (0.006)
     Half  0.246
    权利要求:
    Claims (7)
    [1]

     1. Composition for the manufacture of stabilized blocks of compressed earth and reinforced with esparto (BETCE) comprising:
     - Earth in a proportion of 70-80% of the total dry weight of the composition, 5
     - A binder formed by the combination of slaked lime (Ca (OH) 2), in a proportion of 2-3% of the total dry weight of the composition, and Portland cement, in a proportion of 12-15% of the total dry weight of the composition, and
     - Esparto fiber in a proportion of 12-13% of the total dry weight of the composition.
    [2]
     2. Composition according to claim 1, characterized in that it has a thermal conductivity with values between 0.137 W / m · K and 0.164 W / m · K.
    [3]
     3. Composition according to any of claims 1 or 2, characterized in that the size of the esparto fiber is between 10 and 30 mm. fifteen
    [4]
     4. Stabilized block of compressed earth and reinforced with esparto (BETCE) comprising the composition defined in claims 1-3.
    [5]
     5. Method for the manufacture of stabilized blocks of compressed earth and reinforced with esparto (BETCE) comprising the following steps:
     i. Mix the following components: 20
     - land in a percentage of 70-80%, of the total dry weight of the mixture,
     - binder, formed by the combination of slaked lime (Ca (OH) 2), in a percentage of 2-3% of the total dry weight of the mixture, and Portland cement, in a percentage of 12-15% of 25 dry weight total mix, and
     - esparto fiber, in a percentage of 12-13% of the total dry weight of the mixture,
     ii. Add water to the mixture obtained in i), in a percentage of 45-55% of the total dry weight of the mixture, and knead for a time less than or equal to 5 30 minutes,

     iii. Compact the mixture obtained in ii) to obtain a stabilized block of compressed earth and reinforced with moist esparto (BETCE),
     iv. Dehydrate the wet BETCE block obtained in iii), and 35
     v. Cure the dehydrated BETCE block obtained in iv) for 7-9 days.
    [6]
     Method according to claim 5, characterized in that the size of the esparto fiber used in the mixture is between 10 and 30 mm.
    [7]
     7. Method according to claim 5 or 6, characterized in that the dehydration stages iv) and curing v) are carried out at room temperature. 40
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