Aging accelerated climate

Jelle, B.P. (2012) Accelerated climate ageing of building materials, components and structures in the laboratory. /. Mater. Set, 47, 6475-6496. 

Rehabihtation systems involving structural adhesives have been used for many years in on-site repair and strengthening of timber structures. However, because they exhibit excellent initial joint strength when tested in standard climate conditions, there has not been a major concern about their service durability and reliable and reahstic accelerated ageing tests do not, therefore, currently exist [20]. 

Much work has been undertaken on the Accelerated ageing of adhesive joints. Although the results of such work are valuable, there is no substitute for testing of joints after exposure to a range of actual climatic conditions. Among the most severe climates are tropical dry and tropical wet climates. 

The problem of the acceleration of normal ageing and therefore the ability to predict the long-term strength of GRC was discussed. The model proposed by Proctor was presented in terms of an acceleration factor for example, that one day in water at 50°C is equivalent to approximately 100 days of weathering in UK climatic conditions. That approach was questioned by Purnell and Beddows (2005), who observed that using hot water may lead to severe mistakes in the estimation of the product s durability, because other strength loss mechanisms that are not significant at service temperature may be introduced. 

Accelerated aging is achieved in artificial weathering by increased loads compared with outdoor weathering (e.g., radiation intensity). Here, the number of simulated climate factors is reduced (e.g., night and winter periods are neglected) or their cyclic change is neglected (e.g., temperature and humidity variations) [208]. 

Table 8.S Acceleration time factor of ageing of GRC in hot climates relative to the cooler UK weather (after Aindow et al. [78])...

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