June 11, 2007

Recycling

CIRCA challenges accuracy of Star report

The use of fly ash in concrete manufacturing is a practice that is used worldwide

Jean Sorensen

Correspondent

The Association of Canadian Industries Recycling Coal Ash (CIRCA) has come out in support of the use of fly ash after Toronto press reports suggested using fly ash in the concrete lead to the collapse of the Montreal overpass.

Anne Weir, CIRCA’s executive director, said the Toronto Star article is inaccurate about the fly ash in the concrete. Contrary to assertions that it is a cost-cutting additive good only in small amounts, she reported that fly ash is widely acknowledged as a performance-enhancing supplement to cement. It’s ability to increase strength and reduce corrosion or cracking in concrete improves durability and extends the life of structures.

The use of fly ash in concrete manufacturing is a practice that is used worldwide. The Confederation Bridge, linking Prince Edward Island and New Brunswick, is just one great example of fly-ash use. The bridge is a world-class structure, designed to last 100 years in a challenging environment.

Weir said that it was unfortunate that unsupported comments on the use of fly ash were given precedence over an objective or balanced portrayal of the facts. The Canadian industry and government recognize the use of “supplementary cementing materials” like fly ash contributes to improved technical performance and sustainability objectives. To dismiss the recycling as “cheap by-product(s) of manufacturing processes” is irresponsible, she claimed.

The LEED (Leadership in Energy and Environmental Design) System rewards sustainable practices that demonstrate a life-cycle approach to building construction. This approach is widely supported by other socio-political leaders like Canada Green Building Council and the Federation of Canadian Municipalities. Over the last several years, many Government of Canada building projects have been designed and constructed in accordance with LEED criteria.

CIRCA press release information said that concrete is often taken for granted and the public fails to recognize it is a highly complex material that continues to develop months and even years after it is placed.

Industry and government have invested a great deal of effort to maximize, communicate and capitalize on concrete’s strengths and there is much at stake. That is why balance is important, why a team of engineers will need months to ascertain causes of the overpass failure, the released information says.

CIRCA promotes the responsible use of fly ash concrete in keeping with standard construction practices and appropriate pre-testing of mix designs with region-specific materials is required to assure constructability. The application plus the environmental conditions on site determine the specific methodology for a particular job.

CIRCA and its industry colleagues are offering their final seminar, co-sponsored by CSCE, on “Responsible Use of Supplementary Cementing Materials in Performance-based Specifications” in Montreal on November 29th.

CIRCA promotes the recycling of coal combustion products, produced by coal-fired electricity generation, to be used in superior concrete products. CIRCA collaborates internationally with other industry organizations, including the American Coal Ash Association, the European Coal Combustion Products Association and the United Kingdom Quality Ash Association. >

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