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Zawartość zarchiwizowana w dniu 2024-04-30

Unburnt clay building products

CORDIS oferuje możliwość skorzystania z odnośników do publicznie dostępnych publikacji i rezultatów projektów realizowanych w ramach programów ramowych HORYZONT.

Odnośniki do rezultatów i publikacji związanych z poszczególnymi projektami 7PR, a także odnośniki do niektórych konkretnych kategorii wyników, takich jak zbiory danych i oprogramowanie, są dynamicznie pobierane z systemu OpenAIRE .

Rezultaty

One of the main marketing arguments of unburned clay building products used in interior surfaces is their capability to balance the humidity variations inside the houses. According the test results this capacity correlates strongly with the clay content of the products and in some extent with other factors. The result can be exploited in all the unburned clay building products that are meant for interior surfaces. Typical products are bricks for partition walls or inner layer of exterior walls as well as plasters and wall tiles. Tests were carried out with bricks, tiles and plasters made of unburned loam and other nature-based raw materials. According to the test results the main factor that increases the humidity adsorption and desorption (balancing) capacity is high clay content. Other less important factors are organic additives, addition of water glass and manual (low) compaction. After the test results were available all the partners exploiting this result have made plans to use as loam that has as high clay content as possible in their future production. The scientifically proved high humidity balancing capability of the developed products will increase the market share of them in construction material field. The result is an instruction for producers to choose the right kind of raw materials and production technique. Until now there has been very little systematic research on the field. Big amount of builders and other experts on the field are convinced that manually produced bricks made of sandy loam have the better humidity balancing capability than industrially produced bricks made of clayey loam. Concerning bricks and wall tiles this was proved to be other way round. The shrinkage problem hinders the use of very clayey loam in plasters in future too but the properties can be improved by adding organic fibres. The acquisition of loam could be combined with transport of left over loam from street works and therefore this field has connections to soil science.
One of the main obstacles for a wider use of unburned clay building products especially for the porous ones has been their brittleness in transport and mounting. The strength of the products can be increased considerably by adding wood fibre to the loam. Adding starch or carboxy-methyl-cellulose has also a slight positive effect. The result can be exploited in all the unburned clay building products, but is most suitable in techniques where loam is first liquefied. Typical products are loam–wood wool acoustic panels, and light weight bricks and blocks. Adding wood fibre to loam has been exploited long time in ceramic industry, but adding the fibres to unburned products and defining the most suitable type of fibre is a new innovation. Prototypes were then made of unburned loam, wood fibre and other nature-based raw materials. According to the test results the prototypes with wood fibre had considerably higher strength than the prototypes without fibres that were manufactured before. The new technique will make possible a large range of new clay products. The better strength of the developed products will increase their market share in construction material field. The result is an instruction for; 1. product manufactures to mix loam and wood fibre in a right proportion and to use proper production technique, 2. wood fibre producers to produce right kind of fibre for products. The porous unburned clay building products on the markets suffer from the fragility in transport and mounting but until now there has been no research on how to overcome this problem. The bending strength and elasticity in case of impacts of dense products are increased considerably with use of wood fibre too. Furthermore the shrinkage problem related to clayey loam in plasters can be avoided to some existence adding wood fibres. The acquisition of loam could be combined with transport of left over loam from street works and therefore this field has connections to soil science.
Clay builders and product manufacturers have found wet tensile strength a more suitable parameter than geo technical measures that are developed for highway and foundation engineering. A new quick and reliable apparatus for testing wet tensile strength "Cohesion test device" was developed in this project for the craftsmen and small enterprises that have to be able to determine the loams quality as a building material (binding capacity) quickly and without laboratory tests at the digging site. The apparatus can be exploited when measuring sandy loam (clay content from 5 % to 30 %). Typical products that can be manufactured from such a loam are dense bricks, mortars and plasters as well as rammed structures. The correlation between the geo technical measures and wet tensile strength of a loam was researched for the first time in this project. Cohesion test results correlates with other wet tensile strength test results. The apparatus and the testing method were developed as the first thing of the project. Prototype devices were supplied to all the partners for testing the loam for test sample phase. The apparatus and its instructions are now ready for distribution. The quality of unburned clay building products and structures will be higher when the properties of the loam are better known. Standardizing the test methods, and products will increase the acceptance of customers for clay building in general. The result is a manual apparatus for small-scale producers and craftsmen to test the wet tensile strength of moisten sandy loam. Until now there has been very little research and development on the field. The old wet tensile strength test method was developed in the 1940s and is described in a German pre-norm. (DIN 18952). It has been the most precise testing method but it is not suitable for a field test, due to its time consuming preparation of the samples and the complex apparatus. Furthermore it is not applicable with sandy loam types that are used for loam plasters and mortars. The new testing apparatus is better in sandy loam types than the old because of its quickness and reliable results. The acquisition of loam could be combined with transport of left over loam from street works and therefore this field has connections to soil science.
Paper recycling enterprises are continuously seeking for new application areas for the ever-growing amount of different paper and cardboard fractions. New application areas are sought as well for new fractions, such as juice packages, as for traditional fractions, such as household paper, in order to find more valuable application and better profitability for this material. In this project a method was developed in order to separate pure newspaper from household paper containing unwanted fractions such as kaolin and metal staples with the help of shredder, and air and magnetic separation. After the separation the shredded pure newspaper can be fiberized with commonly used machines to make raw material for various purposes. The method can be exploited by paper recycle enterprises alone or their co-partners that buy the shredded household paper and do the separation and fiberizing work. The end users are producers of unburned clay building products as well as producers of cellulose fibre for thermal insulation applications. Air separation is commonly known in agricultural applications and magnetic separation for instance in community waste recycling, but adapting them in a production line that transforms recycled paper into cellulose fibre is a new innovation. At the moment there exists a schematic plan for the production line and both air and magnetic separation has been proved to work in practice. The weight difference proportions have been defined between different fractions of shredded household paper (pure newspaper, newspaper with staple and kaolin containing paper).With the new method more valuable application and better profitability can be found for the newspaper fraction of household paper. The result is a schematic production line plan and experience from the separation. At the moment cellulose fibre for thermal insulation is mainly produced from the newspaper sheet edges that are cut of in the final phase of the newspaper production. The new method makes much larger raw material resources available with competitive price. This is important in countries (i.e. in Middle Europe) where recycled news paper is not collected separately and the industries using recycled paper are suffering from lack of raw material. The use of wood fibre links this construction field to waste paper recycling field.
The application area of unburned clay building products in Europe has always been limited to structures covered from weather due to the fact that loam is soluble to water. In this project it was proved that adding linseed oil to the product increases considerably their water resistance. Water resistance could be improved with many other additives too (cement, bitumen etc.) but with linseed oil the product has very little environmental impact. The result could be exploited in various products for external surfaces. The typical applications would be facade slabs, external plasters and roof tiles. In case of external plaster it should be considered that diffusion permeability of a linseed oil stabilized loam is very low and can cause condensation in the structure of external wall. This is not a problem of a facade slab assembled to a frame that allows ventilation behind the tile. The use of linseed oil stabilized loam in roof tiles is limited to arid climate because the composite gets very soft when soaked in water. This would make the maintenance of the roof difficult in humid countries in the wintertime. Technically these products would be suitable for bathrooms or kitchens as well but the emissions of linseed oil limits the use of it in internal surfaces. Possibly it could be used as the first layer of an internal plaster as a humidity barrier, but that requires more research. The effect of linseed oil is stated before in literature, but the applications that suits modern building is a new innovation. Prototypes containing loam, linseed oil and other nature-based raw materials have been made and tested in this project and the above-mentioned properties were found. A linseed oil stabilized clay facade slabs would have great aesthetic potential and environmental benefits with competitive price. The result is a plan of consistence for a new product and the constructional systems of it. At the moment facade slabs are made of cut and polished natural stones, concrete composites, ceramic, glass etc. that have rather high environmental impacts. Unburned facade slabs will not be soaked in water and have the problems of roof tile. In many cases linseed oil stabilized loam slabs could offer an environmentally friendly alternative for the conventional facade slabs. The acquisition of loam could be combined with transport of left over loam from street works and therefore this field has connections to soil science.

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