NEXT GENERATION OF SUSTAINABLE CEMENT BLENDS

With an ever-increasing focus being placed on Ecologically Sustainable Development and sustainable construction, reducing Australia’s carbon footprint is clearly a major challenge for all Australians, from families and businesses, to governments – Local, State and Federal.

ONE company that has been helping to meet this challenge for over two decades is leading Australian blended cement supplier, Independent Cement and Lime Pty Ltd (lCL), which has developed a range of specialist ‘sustainable cement’ blends specifically formulated to reduce the environmental impacts of cementitious binders used in concrete and stabilisation products. Marketed under the banner Ecoblend, these blended cement products utilise Supplementary Cementitious Materials (SCMs) such as slag and fly ash to deliver a range of environmental benefits, including a reduction in CO2 equivalent emissions during manufacture, efficient utilisation of a recovered resource stream, and a significant reduction in the energy required to manufacture the product, without adversely effecting product quality or performance.

Cement Production – The Need for a Sustainable Approach

Cement is typically made from limestone, which is burned in gas and coal fired kilns at extremely high temperatures (approx. 1450°C), transforming the limestone both chemically and physically, into a lumpy grey material known as clinker. This clinker is then crushed into cement powder in grinding mills. Cement is the key ingredient, the ‘glue’ that binds the sand and aggregate to make concrete.

Concrete is the most important of all building materials. Its ready availability, durability, versatility and relative cost have ensured its continued (and growing) use over many decades. However, the industry is responsible for significant levels of greenhouse gas emissions, primarily from the chemical reaction that occurs when the limestone is burned. The mining of the limestone and transport of the cement, together with the energy required during manufacture, add further to the CO2-e output.

Indeed, it is estimated that some 900kg of CO2-e emissions are generated for every tonne of cement manufactured, with the cement industry alone responsible for approx. 5% of global CO2-e emissions.

Having recognised the very real environmental issues associated with the manufacture of cement some years ago, ICL has since that time invested heavily in the development and production of a more environmentally sustainable alternative – Ecoblend.

Ecoblend – Supporting a Greener Future

Following extensive research, development and major investment in plant and equipment, ICL commenced production of its Ecoblend range of environmentally friendly ‘cement blends’ in 1991. In these Ecoblend products, conventional cement is partly replaced with SCMs, typically blast furnace slag or fly ash.

Introducing these supplementary materials has had a significant impact on the CO2-e emissions generated by cement manufacture, achieving this in a number of ways:

• Ecoblend products contain a minimum of 30% SCMs significantly reducing the demand for clinker-based cements and hence the requirement for the burning of fossil fuels used in the energy intensive cement clinker production, as well as reducing the emissions that occur during the burning process itself. For each tonne of SCMs used, CO2-e emissions are reduced by 700kg.
• The use of Granulated Blast Furnace Slag (GBFS) as the cement replacer means that the slag, which is a by-product of steel production, is no longer considered ‘waste’ and is not put into landfill.

Ecoblend is in fact a superior cementitious product, offering increased durability or longer life, particularly in adverse environments (e.g. salt water, sulphate environments, etc.), meaning that the concrete will last longer – further reducing its environmental impact.

Not surprisingly, this combination of environmental benefits and material quality has resulted in a strong demand for Ecoblend products. In fact, Ecoblend has proven to be so successful, that ICL’s current production facility is running at capacity – producing some 250,000 tonnes per annum – delivering a staggering saving of some 160,000 tonnes of greenhouse gas emissions each year.

Contact Independent Cement and Lime Pty Ltd for more information on 03 9676 0000.

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