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Concrete In Australia : June 2009
8 Concrete in Australia Vol 35 No 2 e Concrete Institute is taking a leading position on reforming concrete durability design and construction by establishing a special group to examine durability reform with a view to developing a new performance-based code. e Institute is also organising a series of national workshops on durability, to be held in June (also see leaflet with this issue). Infrastructure decay is widely acknowledged as a major issue worldwide. For example, in the US, the American Society of Civil Engineers reported in 2005 that US$1.6 trillion was required to address US infrastructure needs. Although Australia s problems are not on the same scale as that of the US, we have no cause to be complacent. One Australian port authority engineer has said that he and his colleagues had repaired three of their structures that were only about 20 years old and that they had not yet seen one of their marine structures achieve its design life. is is not an uncommon story. A survey of experts in 2008 found that just throwing money at the issue "will do nothing to resolve a lack of vision in setting of priorities and a lack of leadership when it comes to confronting the most difficult challenges." e Concrete Institute of Australia has recognised the problem as having two dimensions: durable structures are essential to a strong economy and durable structures Concrete Institute leads on reforming durability design and construction are an important environmental tool. e Institute has also recognised the need for leadership and through its membership is well placed to provide the necessary leadership in the concrete durability arena. To this end, a committee (Z7) has been formed to work on the overall issue of durability. is committee comprises many industry experts involved in developing a strategic plan for durability design and construction in Australia. e Z7 committee will conduct workshops around Australia in June where it will outline the current status of durability design, the problems facing the design and construction sectors and possible options for a way forward. ere will also be various workshops targeting inputs from asset owners, design engineers, architects, materials suppliers and construction contractors. One of the major issues to be explored is the development of a performance-based code. While many in the industry believe the necessary reliable performance tests are not yet available, others are already using a diverse range of performance criteria in specifications. is diversity makes it difficult for suppliers and construction contractors. If performance tests are to be specified, then harmonisation through codes would be useful. Another major issue to be addressed is the lack of options for concrete choice in the Australian codes. For example, the major code for concrete structures, AS3600, provides only one option for marine structures which is 50MPa concrete with 50mm cover. is is extremely limiting and potentially very costly. e Z7 committee believe that, in some cases, the required 40-60 year design life may be under-achieved by some margin and indeed another Australian code, AS4997 says that the same design will only provide a 25-year life. While AS 3600 is the "leading code" for concrete structures in Australia there are various other codes providing guidance for the same environments. Piling, water retaining, marine and bridge structures all have separate design requirements for concrete and these are often in conflict. ere is a strong case for having one code that covers all durability aspects in concrete through extracting durability provisions that are listed in all the other codes. However, durability is a complex subject. On major projects, advanced deterioration models used by specialists ensure the safest and most economical way of approaching design. Smaller projects however need unsophisticated "deemed to comply" rules that, although conservative, can be driven by the general engineering community. ere is no better time than now to address the issue of concrete durability design. Australia s durability standards have not moved forward significantly in 30 years whereas our materials and manufacturing methods have developed greatly. e Concrete Institute is keen to provide leadership to overthrow the old orthodoxy in concrete durability design NEWS