engleski

Sustainable Insulating Composite from Almond Shell

New generations of eco-friendly and sustainable insulating materials are prepared as composite materials in which the plant fibrous material (byproduct of agricultural activity) is bonded by inorganic binders. In addition to good mechanical properties and low density, these composite materials also possess good insulating properties. In this paper the possibility of the preparation of composite material on the basis of almond shell with potential application as insulating boards has been studied. Composites from milled and sieved almond shells and wood- wool bonded with Portland cement and sodium silicate solution have been prepared. The hydrolytic properties, flexural strength, thermal properties, and calorific value of prepared composites were investigated. Composites prepared with Portland cement alone had setting times greater than 24 h, and further test were carried out on composites prepared with the addition of sodium silicate solution as a binder. Optimal mechanical properties, density, and water glass consumption had composites prepared with almond shell particle size from 1, 25 to 2, 5 mm. Mechanical testing of samples with density of 0, 503 g/cm3 showed that strain in range of 144- 180 N causes a maximum deformation of 12 cm and the stress of 0, 12 MPa causes irreversible deformation and cracking. Thermal conductivity of prepared composite was 0, 203 Wm-1K-1 and its thermal diffusivity was 0, 124 mm2s-1. Calorific value test showed slightly higher results than wooden materials with low sulphur and chlorine content. Examined mechanical and thermal properties of composite material are comparable to the properties of insulating materials available on the market. The advantage of such material is so-called binding of CO2, because by production and use of this kind of material, CO2 embedded in the plant material is bonded throughout the lifetime of the building.

composite, insulating material, almond shell, thermal conductivity, thermal diffusivity

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