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The use of sandwich panels based on polyurethane core will be restricted due to the tightening European fire-resistance and environmental regulations. Adhesively bonded sandwich panels with mineral wool core are the most promising products to replace them. However, they are characterised by an important disadvantage when compared to polyurethane core sandwich panels: humidity and other environmental factors have an important influence on the long-term durability of the panels. The large number of environmental factors included in the ageing process and their complicated interactions make the theoretical approach of ageing difficult. Long-term tests under actual end-use conditions are often the only reliable way of measuring the ageing of adhesive joints. However, this kind of testing is usually too time consuming and uneconomical in practice. A methodology for predicting the long-term durability of adhesively bonded sandwich panels under different end-use conditions was developed. The methodology is based on modelling of the ageing phenomena on the basis of short-term laboratory tests and well-known thermodynamic laws, diffusion equations, etc. The model is then combined with the climatic data of the end-use conditions to yield a long-term durability forecast. A microclimate, i.e. the internal climate of mineral wool, controls the strength loss of the whole structure. However, the microclimate inside sandwich panels is not well known. Hence, parameters of microclimate were measured in field conditions. When correlation between microclimate and natural climate together with correlation between accelerated and natural ageing tests were determined, the strength loss of a panel under certain conditions could be forecast on the basis of meteorological data

Additional information

Authors: HAUTALA M, Rautaruukki OY, Hämeenlinna (FI);DELANOE R, Arcelor, Montataire (FR);REENTILÄ M, University of Technology of Tampere, Tampere (FI)
Bibliographic Reference: EUR 21412 EN (2005), 112 pp. Euro: 25
Availability: The paper version can be ordered online and the PDF version downloaded at:
ISBN: ISBN: 92-894-9791-2
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