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Euro demands undermine aggregate unity

CONFLICT BETWEEN European aggregate experts and the European Commission's demands for unprecedented safety tests has put ten years of work to harmonise European aggregate standard at risk.

Members of a European technical committee which is struggling to agree a final draft of the proposed standard fear a forthcoming mandate from the EC on safety parameters could be the final straw which wrecks the work.

This mandate proposes a series of new tests for radio-activity, alkali- silica reactivity and other safety parameters which might have to be included in the standard to prove aggregates are 'free from harmful substances'. This addition, it is feared, could delay publication for several years.

Dr Philip Nixon, chairman of the European concrete aggregates sub-committee and Building Research Establishment centre for concrete construction technical director said: 'Our concerns are based on the current draft of the mandate. What the official version will say when we receive it at the end of the year we don't know.'

Mandates have to be issued by the EC to European standards-drafting body CEN before a new standard has official status. But CEN did not publish the discussion document until last year and the current 'Inquiry' process had already run into serious problems with the concrete aggregates section before the draft mandate became available.

Nixon said there were three main areas of difference. 'The Germans want specific limits on chlorides in aggregates, and a new test for freeze- thaw resistance. The French have particular concerns over tolerance on grading limits,' he said. 'But at a meeting last week we agreed a revised draft for circulation which we believe represents the way forward.'

If this draft can reconcile the differences, a formal vote of the technical committee would normally approve it for publication as a European standard. If not, the draft will be abandoned and the technical committee, probably with new members, would have to start again from scratch.

Chairman of the CEN aggregates committee, British Standards Institution project manager Brian Feldman, said that in theory a European standard for aggregates could be published in advance of a mandate to CEN, 'but it would not be a Harmonised standard'. He accepted there was a risk of delay, but added: 'It was never considered realistic that new first generation ENs (European standards) would all be completed at the same time.'

Dave Parker

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