Keywords: waste, polymers, finite element analysis, window, subframe.

The increasing quantity of waste material is associated with the continuously increasing need for their recycling and reuse. An important subgroup of waste materials are polymers. Selected polymers with suitable thermal-technical and physical-mechanical properties can also be used with advantage in civil engineering. The application of recycled polymers suitably supports the decrease in energy exigency and thus the area of sustainable engineering.

Recognition of waste polyethylene material characteristics is important for possible application of this material in building products. In addition knowledge of this material is essential for quality of the whole structure in which the material is applied. The conclusions of the material characteristics research brought rather interesting findings. High-density polyethylene (HDPE) material almost does not loose its properties by types recycling. The identified values of the individual material characteristics are almost equal to generally acknowledged values of virgin HDPE material. High quality material may be obtained from high quality recycling technology. Certainly, material values differ since a number of HDPE modifications exist, however the average values are close to the virgin material values. Material characteristics values vary with the worse recycling technology (mostly degraded) due to impurities and the presence of other materials particles. For the purpose of manufacturing products intended for the construction industry it is recommended to select the best available recycling technology and always determine the most important material characteristics as reference values if material from other waste processor is used. In case of a material with normal flammability it is possible to increase its fire response class to B quite easily by using a burning retardant while retaining similar material characteristics as the non-retarded material. This class enables material application in buildings. Bulk weight of retarded materials is approximately 20% higher, the heat conductivity coefficient is 11% lower and in case of mechanical properties it achieves values which are approximately 10% lower with the exception of the elasticity coefficient which is 10% higher. Another interesting conclusion of the material characteristics research is production technology dependence and recycled polyethylene material characteristics. In the case of compression moulded boards, the values of heat conductivity coefficient and rigidity values are lower than in case of material produced by extruding. Stress-rupture module values are approximately 30 to 40% higher for the retarded material compared to the non retarded one, where the stress-rupture curve corresponds to virgin polyethylene. Compression tests document that pre-stressing given to the material by compression is positively reflected in the elasticity module. This may be increased by up to 15% and is positively reflected in the material bearing capacity.

Based on the knowledge of the recycled polyethylene material the design and prototype of a product for civil engineering is made: a subframe for opening fillups in passive houses. A contribution to sustainable development is made not only by the savings in energy with the application of the above product, but also by the use of waste HDPE and thus extension of its life cycle.

The shapes of the product respects both the requirements for the detail of the contact of the fill-up for the opening and cladding, as well as the requirements for functionality and stability for the entire service life.

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £140 +P&P)