Method for producing a masonry bond

Abstract

The invention relates to a method for producing a masonry composite (1) from masonry blocks (2) which are laid in layers one above the other, each separated by a bed joint (3), wherein a thin-bed adhesive is applied to contact surfaces of the masonry blocks (2) for bonding the layers in the bed joint (3), wherein snail slime or a substitute for snail slime is used as the thin-bed adhesive.

Description

[0001] The invention relates to a method for producing a masonry composite.

[0002] The construction and real estate sector contributes approximately 40% of global CO2 emissions. Given the worsening raw material shortages, rising construction material costs, and ultimately the escalating climate crisis, it is essential to research cost-effective, locally sourced, and renewable resources for construction. Renewable and regionally available resources can help reduce the construction sector's environmental footprint while mitigating rising construction costs by decreasing reliance on expensive and scarce raw materials. The search for alternative building materials is a key component of global efforts to combat climate change.

[0003] In a life cycle assessment, from production and use to disposal, masonry building materials exhibit considerable resource and energy demands. The resources required for these materials are becoming increasingly scarce. Furthermore, both the extraction of these resources and the production and subsequent disposal of the building materials cause significant environmental pollution.

[0004] The influence of exterior walls is particularly striking. Using multi-family dwellings as an example, 'embodied energy' – the energy consumed in the production and construction of the buildings – accounts for approximately 30% of the building's total energy demand. The interior and exterior masonry are responsible for roughly 70% of the embodied energy used in residential construction.

[0005] Masonry is a result of the interplay between material, construction method, and building process. Traditionally, the masonry block is laid on a horizontal joint, bonding together with the mortar. The use of dimensionally accurate, precision-cut masonry blocks allows for a reduction in joint width and the application of thin-bed mortar or thin-bed adhesives.

[0006] The jointing material performs several functions: 1. It securely bonds the masonry bricks together. 2. It compensates for unevenness or irregularities. 3. It acts as a sealant and can improve heat and sound insulation. 4. It improves mechanical properties such as strength and durability. 5. It fulfills aesthetic functions within the group by adding color and texture to the walls.

[0007] The construction industry is a major driver of climate change. In times of global warming, the research into sustainable building materials and components is becoming increasingly important. Alternatives to the climate-damaging manufacturing processes of conventional mineral masonry materials are urgently needed. The use of renewable resources in building material production is becoming ever more crucial.

[0008] Strawstone research is a young field of research, and the search for a suitable jointing material for strawstones follows logically.

[0009] Reducing the ecological footprint of masonry techniques throughout their entire life cycle, from resource extraction to end-of-life, can be achieved through the implementation of diverse sustainability strategies.

[0010] The efficiency strategy aims to minimize resource consumption throughout the entire process. This includes both the efficiency of material use and energy efficiency in the production process and during the material's use phase.

[0011] The consistency strategy involves using environmentally friendly and renewable resources both in the manufacturing phase and in the operation of the finished structures. This can include using renewable energy sources or building materials whose production causes less environmental damage.

[0012] The strategy of sufficiency describes contentment with decidedly modest demands. It's about being satisfied with the available resources and limiting oneself to what is truly necessary. This can manifest itself in a respectful use of materials and a sustainable, less demanding approach to the planning and execution of construction projects, but it also includes the way buildings are used and operated.

[0013] By integrating these strategies into masonry methodology research, the industry can significantly reduce its environmental footprint and make an important contribution to achieving global sustainability goals.

[0014] Various research approaches, taking into account the aforementioned sustainability strategies, are attempting to replace traditional masonry building materials. These research efforts differentiate between masonry blocks and mortar joints. Current research on masonry building materials demonstrates the great potential of straw blocks. Further research is analyzing suitable jointing materials that, in addition to fulfilling the aforementioned requirements, also meet sustainability criteria.

[0015] Research into masonry materials with a focus on sustainability is extensive. Considerations regarding sustainable masonry units largely relate to the jointing material. Efficiency research is being pursued through a variety of methods, such as refined procedures for calculating component designs or optimizations in the firing processes of manufacturing techniques. Another research focus is the investigation of the possibility of replacing the resources required for masonry materials with alternatives, such as abundant desert sand, the use of which is being promoted by 3D printing techniques. Furthermore, an important area of ​​research is the examination of the use of recycled materials, including crushed brick, used concrete, and other industrial byproducts such as fly ash or slag.Attention is also paid to the use of natural resources such as clay, hemp, and similar materials, as well as forestry and agricultural byproducts like straw, which exhibit minimal environmental impact and biodegradability. Overall, the research aims to improve resource efficiency and develop more sustainable manufacturing processes in line with a fully circular economy. A central theme within efficiency research revolves around the concept of modular and deconstructable building components. The focus here is on developing components that can be easily disassembled and reused to minimize material waste and promote resource-conserving recycling practices.

[0016] Efficiency research focuses on the optimized use and disposal of masonry materials. This includes considering both the durability of these materials and their required maintenance. One aspect of sustainable construction is the selection of materials with longer lifespans that therefore require less frequent replacement.

[0017] The sustainability of masonry materials is assessed across their entire life cycle, from production to end-of-life. Research initiatives therefore focus on developing strategies that enable the reuse and recycling of these materials after their service life, in order to create a circular economy of resources and overcome the linear "production-use-disposal" mentality.

[0018] Consistency research focuses on innovating the manufacturing processes of masonry materials to better integrate renewable energy sources. This is already economically feasible for autoclaved products, such as calcium silicate bricks. Because these are produced at relatively lower temperatures, they require less energy and are therefore ideal candidates for such changes. Furthermore, another research focus is the development of new binders. The aim is to develop materials that emit less CO2 during production than conventional Portland cements. These newer binders can thus make a significant contribution to reducing the carbon footprint of the construction industry.

[0019] Sufficiency research focuses on supporting and shaping the paradigm shift from a growth-driven society to a more environmentally conscious and sustainable form of society. This means redefining the goals of prosperity and well-being by no longer basing them solely on economic growth, but also taking into account aspects of environmental compatibility and resource conservation.

[0020] The research focuses on sufficiency by exploring methods and strategies that make it possible to manage with fewer resources while simultaneously ensuring a high standard of living and social well-being. This can be achieved through expanded use, reuse, and longer life cycles of goods, as well as by reducing waste and excess.

[0021] The raw materials for common masonry jointing materials are finite: Conventional masonry jointing materials, which typically include cement, lime, sand, water and various additives, are based on finite natural resources.

[0022] A concrete example of such a limited resource is sharp-edged sand, which is ideally suited for the construction process. This is already a scarce commodity, leading to increasing demand and thus higher prices, even resulting in a thriving black market for sand illegally mined in Asia's economic growth markets. In contrast, desert sand, despite its abundant occurrence, is only of limited use in the construction process, particularly in concrete production, due to its rounded structure.

[0023] Lime mortar, another widely used building material, is also affected by the dependence on finite resources. The necessary raw materials are now often extracted only with considerable environmental damage, which impairs both ecological and economic sustainability.

[0024] Cement, a widely used material for mortar joints in masonry, is extremely energy-intensive to manufacture and is a major CO2 emitter. It is estimated that the cement industry is responsible for about 7% of global CO2 emissions. This is due to the enormous energy consumption during production, but also to the chemical process itself, in which limestone is burned to produce lime – a process that releases significant amounts of carbon dioxide.

[0025] Artificially produced masonry jointing materials, such as cement- or lime-based mortars, deplete our natural resources because they require finite raw materials for their production. Furthermore, the manufacturing process, which involves sometimes high temperatures, relies heavily on non-renewable energy. In the final phase after their use, at the end of their life cycle, these materials are often simply downcycled, meaning they are transformed into lower-quality products instead of being recycled in a way that preserves their value and conserves resources. This results in a cycle of resource and value loss. What is needed is an ecologically responsible masonry jointing material that manages the entire life cycle—from resource extraction through production and use to final treatment—in an environmentally sustainable manner.

[0026] Conventional manufacturing processes for synthetically produced masonry jointing materials, such as cement, require extremely high temperatures ranging from 900°C to 1450°C. These high temperatures are crucial for the chemical changes that occur during the cement manufacturing process. However, this results in considerable energy demands, as these temperatures can only be reached with significant energy input. This process is not only time-consuming but also resource-intensive and has high CO2 emissions, since most of the energy required to reach these temperatures comes from fossil fuels.

[0027] DE 10 2022 134 711 A1 describes a block with a first, lower bearing surface and a second, upper bearing surface, which are essentially parallel to each other, and orthogonally aligned, parallel side surfaces and end faces which, together with the bearing surfaces, essentially form a cuboid body. The block has at least one opening extending from the second bearing surface through the body to the first bearing surface, and at least one groove extending from the opening towards at least one of the end faces and / or side faces. Furthermore, a method for constructing masonry from blocks is described, in which several rows of blocks are arranged one above the other and horizontally offset from each other and bonded with an adhesive using a thin-bed method, wherein a water-soluble adhesive is used.

[0028] CN 107 265 935 A describes a process for the production of machine-made dry sand mortar. The dry-mixed surface mortar is produced from the following raw materials: cement, machine-made sand, coal ash, water, an air-entraining agent, and a compactor. The process includes the steps of mixing cement, coal ash, and water to form an adhesive; mixing the adhesive with machine-made sand to form an adhesive sand material; adding the air-entraining agent and the compactor to the adhesive sand material in a density ratio; stirring for 3–5 minutes; and allowing to stand to obtain the dry-mixed surface mortar from machine-made sand. The machine-made sand is used to completely replace natural sand and to produce dry-mixed surface mortar.Simultaneously, an appropriate amount of compactor is added to counteract the fact that the machine-produced sand has a high water absorption rate and is prone to dissociation bleeding. Compared to dry-mixed surface mortar made from natural sand, the compressive strength and tensile strength of the dry-mixed surface mortar made from machine-produced sand are superior to those of the dry-mixed surface mortar made from natural sand, provided the flow properties are similar.

[0029] The invention is based on the objective of providing a novel method for producing a masonry composite.

[0030] The problem is solved according to the invention by a method for producing a masonry composite with the features of claim 1.

[0031] Advantageous embodiments of the invention are the subject of the dependent claims.

[0032] A method is proposed for producing a masonry composite from masonry blocks laid in layers one above the other, each separated by a bed joint, wherein a thin-bed adhesive is applied to the contact surfaces of the masonry blocks in the bed joint for bonding the layers, wherein snail slime or a substitute for snail slime is used as the thin-bed adhesive.

[0033] In one embodiment, straw bricks are used as masonry bricks.

[0034] In one embodiment, the contact surfaces of the masonry blocks are pressed together, in particular by applying a surcharge.

[0035] In one embodiment, the bonded bearing joint is actively dried (for example, by increased temperature) or passively dried.

[0036] According to the invention, a polymer gel and / or a hydrogel and / or polyhydroxyethyl methacrylate are used as a substitute for snail slime.

[0037] In one embodiment, a butt joint is formed between adjacent masonry blocks of each layer, the butt joint being executed with or without bonding by the thin-bed adhesive.

[0038] In one embodiment, the thin-bed adhesive is used to form bed joints and / or butt joints with a maximum thickness of three millimeters.

[0039] In one embodiment, the butt joint is designed to be form-fitting. For this purpose, the masonry blocks can, for example, have contours that are designed to engage with complementary contours of an adjacent masonry block.

[0040] According to one aspect of the present invention, the use of snail slime or a substitute for snail slime made from a polymer gel and / or a hydrogel and / or polyhydroxyethyl methacrylates as a thin-bed adhesive for the production of a masonry composite made from masonry blocks, in particular straw blocks, is proposed.

[0041] Alternatively, plan blocks or materials in brick or plan block similar formats made from non-mineral renewable raw materials can be used as masonry blocks.

[0042] The finite resources used in the construction industry for masonry building materials can be replaced by an ecological alternative using the present invention. This results in masonry that is sustainable throughout its entire life cycle. Compared to conventional masonry, this masonry offers good mechanical and physical properties.

[0043] The present invention provides a method for installing straw bricks in masonry using a thin and ecologically sustainable adhesive joint. For the production of sustainable, ecological masonry using dimensionally stable straw bricks, a thin-bed adhesive made from snail mucin, particularly from terrestrial pulmonate snails, or a snail mucin substitute, is employed. This thin-bed adhesive, made from snail mucin or the snail mucin substitute, can be applied to the straw bricks and develops high strength during a drying process. When the straw bricks and the thin-bed adhesive are bonded under pressure, a particularly strong bond is created.

[0044] Initial tests have shown great potential for the mechanical properties.

[0045] The thin-bed adhesive made from snail slime or snail slime substitute can be used ecologically and reversibly throughout its entire life cycle. Initial source analyses show that snail mucus can be synthetically replicated as a polymer gel and / or hydrogel (for example, pHEMA - polyhydroxyethyl methacrylate) and thus the animal product can be sustainably substituted ("Intrinsically reversible superglues via shape adaptation inspired by snail epiphragm" Hyesung Choa, Gaoxiang Wu, Jason Christopher Jolly, Nicole Fortoul, Zhenping He, Yuchong Gao, Anand Jagota and Shu Yang 13774-13779 1 PNAS I July 9, 2019 1 vol. 116 1 no. 28, https: / / www.pnas.org / doi / epdf / 10.1073 / pnas.1818534116 and Proceedings of the National Academy of Sciences (PNAS) "Superglue becomes reversible - Snail mucus-inspired adhesive bonds extremely strongly yet reversibly," Nadja Podbregar June 18, 2019, https: / / www.scinexx.de / news / technik / superkleber-wird-reversibel / ).

[0046] Extremely thin mortar joints or films of nearly zero to three millimeters make it possible to optimize the building physics and structural properties of the straw bricks across the entire wall area. By reducing the joint area, the significant thermal bridge created by the joints between the bricks and the straw bricks can be considerably reduced. The thin-bed adhesive is particularly suitable for use with dimensionally stable straw bricks. It is applied to the bearing surface of each individual straw brick and serves as a bed for the next layer. Only the bed joints are bonded – that is, the horizontal joints. The vertical butt joints are only bonded in specific applications, such as around window lintels. Furthermore, the bricks are laid using interlocking mechanisms. The thin-bed adhesive, made from snail slime or a snail slime substitute, has a plastic consistency when wet.Due to its gel-like consistency, the surface of the horizontal joints can be easily moistened. The treated straw stones are placed in contact and, in particular, pressed together.

[0047] During the drying process, the thin-bed adhesive develops its dimensional stability and high adhesive strength.

[0048] The present invention represents an environmentally friendly alternative to conventional masonry methods throughout its entire life cycle. Load-bearing masonry made of concrete, calcium silicate brick, clay brick, and clay with associated inorganic jointing materials can be largely replaced. The masonry produced by the present invention achieves strengths that permit the construction of three- to four-story buildings and represents a load-bearing alternative masonry method.

[0049] The thin-bed adhesive made from snail mucin or a snail mucin substitute is completely biodegradable. Complete or partial dismantling of the masonry is possible due to the reversible hardening processes. The masonry components, straw brick and mortar, can be separated.

[0050] The invention presents, for the first time, a method for producing a rapidly renewable, life-cycle-integrated, and environmentally friendly alternative to commercially used masonry methods in Europe. Straw, the primary resource for straw bricks, is characterized by a significantly shorter regeneration time compared to wood. While trees typically take about 60 to 80 years to mature, straw only takes about 10 months to grow. Furthermore, straw is currently a byproduct of agricultural production. Only about 70 to 80 percent of all straw produced is actually used, indicating considerable potential for more efficient use of this material. These factors make straw an extremely attractive and sustainable resource for the construction industry, especially considering its cost-effectiveness and environmental friendliness.

[0051] The starting resource used, thin-bed adhesive snail slime, is highly adhesive after the drying process, but plastically malleable during processing, reversible at any time and ecologically degradable.

[0052] The present invention provides a masonry method that achieves the strengths required for use in load-bearing masonry and is fully recyclable.

[0053] By reducing the joint thickness to a thin adhesive layer, the influence of the jointing material within the masonry is reduced compared to the properties of the straw brick. Improved mechanical and structural properties can be achieved.

[0054] Reducing the joint thickness to a thin adhesive layer results in shorter drying times for the curing process and lower energy consumption for providing smaller quantities of jointing material.

[0055] The very thin joint pattern allows for visually appealing masonry walls.

[0056] The present invention describes a masonry structure made of straw bricks bonded with a thin-bed adhesive. Straw and snail mucin or substitutes, rapidly renewable resources, are used as raw materials.

[0057] The resulting masonry, with its straw bricks and jointing material, exhibits surprisingly good mechanical properties. The entire masonry structure, made of straw bricks and thin-bed adhesive, is sustainable throughout its entire life cycle. The resources used are renewable, ecological, and biodegradable. The masonry is harmless to health, meaning that pollutant-free masonry can be constructed.

[0058] The use and production of straw brick masonry can help conserve the limited resources typically used in the construction industry. Straw, a partially surplus byproduct of grain harvesting, becomes a valuable building material in this context. Thin-bed adhesive made from snail mucin or substitutes is a regional, renewable, and environmentally friendly resource. The production process of straw brick masonry requires less energy compared to conventional building materials, thus helping to reduce the use of our finite resources. Furthermore, straw brick masonry is biodegradable and has a low carbon footprint, making it a sustainable option in the construction industry.

[0059] Particularly dimensionally stable straw bricks, which are especially suitable for creating a masonry structure with particularly thin joints, especially bed joints, can be produced, for example, in the following way: A method for producing a straw brick is proposed, wherein straw chaff is mixed with at least one natural additive that increases the adhesive bond between the straw chaff and water, wherein the mixture obtained is compacted, wherein the mixture is placed in a formwork before or after compaction, wherein the compacted mixture in the formwork is subjected to microwave treatment, wherein the building product obtained is actively or passively cooled and then removed from the formwork. In one embodiment, straw chaff of a length of 1.0 cm to 3.0 cm is used, or straw is chopped to obtain straw chaff of a length of 1.0 cm to 3.0 cm. In one embodiment, the chopped straw is split open. This can have a positive effect on the strength of the final product. In one embodiment, the chopped straw is dedusted before being mixed with water and the at least one additive, as this promotes the formation of effective adhesive bridges. In one embodiment, water is added in such a quantity that the water content of the mixture, based on a dry mixture of chopped straw and additive, is approximately 10% to 30%. In one embodiment, the compression is carried out in such a way that the mixture has a density of at least 200 kg / m³. 3 up to 600 kg / m² 3 This results in strengths that are useful for construction applications. Higher strengths can be achieved in the final product with increasing compaction. In one embodiment, the formwork is closed after compaction. In one embodiment, the mixture of straw, water and at least one additive is heated by microwave treatment to a core temperature of, for example, 10°C to 200°C, in particular more than 150°C to 180°C. In one embodiment, the microwave treatment is stopped after the core temperature is reached. In one embodiment, a formwork made of plastic, in particular polypropylene, is used. In one embodiment, lignin, in particular highly reactive lignin, is used as an additive. In one embodiment, the additive is used in an amount of up to 15% of the starting material straw, based on the dry matter.

[0060] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing.

[0061] It shows: Fig. 1 A schematic representation of masonry bonds.

[0062] According to the present invention, a method for producing a masonry bond 1 is proposed. In this embodiment of a masonry bond 1, the bond between individual masonry units 2 is produced using a suitable jointing material.

[0063] The only Fig. Figure 1 is a schematic representation of masonry bonds 1. On the left is a masonry bond 1 made of straw bricks 2 and comparatively thick bed joints 3 and head joints 4 made of clay mortar. On the right is a masonry bond 1 made of straw bricks 2 with a significantly thinner bed joint 3 made of a thin-bed adhesive made of snail slime or a substitute for snail slime.

[0064] In the first step of producing the masonry bond 1, the straw bricks 2 are coated with the thin-bed adhesive made from snail slime or a snail slime substitute, at least in one bed joint 3. In a second step, the straw bricks 2 are positioned on top of each other. In an optional third step, the contact surfaces of the straw bricks 2 are pressed together, for example, in the masonry bond 1 by applying a ballast.

[0065] In a fourth step, a drying process takes place. This process can be accelerated by increasing the temperature, for example from 20 °C to 50 °C. However, solidification also occurs at room temperature.

[0066] In a fifth step, the grouting or the surcharge can be removed.

[0067] The process can be repeated from the first step to apply several layers of straw bricks 2 until the desired wall height is achieved.

[0068] The present invention enables a very thin joint layer compared to the prior art.

[0069] In a preliminary test, straw bricks (2) were coated with the thin-bed adhesive snail slime. For this purpose, a ventilated casing was constructed around the straw bricks (2) to be bonded. Snails were used to coat the exposed surfaces. The casing was then opened, revealing that the contact surfaces of the straw bricks (2) were completely covered with moist snail slime. These surfaces were positioned on top of each other and pressed together with clamps for 24 hours. The clamping time can be shortened. The clamps were then released, and a bond between the straw bricks (2) was observed. Subsequently, shear tests were conducted on straw brick joints using various mortar materials, including the thin-bed adhesive snail slime.

[0070] Initial tests using the adhesive (snail slime) to bond bricks made of straw resulted in shear strengths of 0.08 N / mm². 2 The composite of straw stones 2 and the thin-bed adhesive snail slime exhibits particularly high strengths. REFERENCE MARK LIST 1 Masonry bond 2 masonry stone, straw stone 3 Bed joint 4 butt joint

Claims

[1] Method for producing a masonry composite (1) from masonry blocks (2) laid in layers one above the other, each separated by a bed joint (3), wherein a thin-bed adhesive is applied to contact surfaces of the masonry blocks (2) for bonding the layers in the bed joint (3), wherein snail slime or a substitute for snail slime is used as the thin-bed adhesive, wherein a polymer gel and / or a hydrogel and / or polyhydroxyethyl methacrylates are used as the substitute for snail slime. [2] Method according to claim 1, wherein straw bricks (2) are used as masonry bricks (2). [3] Method according to claim 1 or 2, wherein the contact surfaces of the masonry blocks (2) are pressed together, in particular by applying a surcharge. [4] Method according to any of the preceding claims, wherein the bonded bearing joint (3) is actively or passively dried. [5] Method according to one of the preceding claims, wherein a butt joint (4) is formed between adjacent masonry blocks (2) of each layer, wherein the butt joint (4) is executed with or without bonding by the thin-bed adhesive. [6] Method according to one of the preceding claims, wherein the thin-bed adhesive is used to form bed joints (3) and / or butt joints (4) with a maximum thickness of three millimeters. [7] Method according to one of the preceding claims, wherein the butt joint (4) is formed in a form-fitting manner. [8] Use of snail slime or a substitute for snail slime consisting of a polymer gel and / or a hydrogel and / or polyhydroxyethyl methacrylates as a thin-bed adhesive for the production of a masonry composite (1) of masonry blocks (2). [9] Use according to claim 8, wherein straw bricks (2) are used as masonry bricks (2). [10] Use according to claim 8, wherein plan blocks made from non-mineral renewable raw materials are used as masonry blocks (2).

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