Concrete technologiesby CW Staff on Dec 6, 2010
What are the latest developments in concrete and how can these boost project sustainability? Construction Week investigates.
Much used as a primary building material throughout the Middle East, the pros and cons of concrete are being increasingly scrutinised as the construction industry looks to the future. Ensuring this essential material can meet new demands for both structural engineering and sustainability is vital to its future use in the region.
Well aware of the need to remain competitive with alternative building products, concrete producers and suppliers are developing new mixes and products. But as well as changes to how the product is actually used in the construction industry, improvements are also being made to its production and material make-up. One of the latest changes is the use of recycled materials in concrete.
“A trend in concrete production is the replacement of cement with ground granulated blast furnace slag (GGBS), which is a by-product of the steel industry, or pulverised fly ash (PFA), which is the by-product of the thermal power plants that use coal for burning in the turbines,” reports a Lootah Group spokesperson. “The replacement levels can be up to 70% in the case of GGBS and 30% in the case of PFA; this minimises the use of cement, which is the major contributor in carbon pollution.”
This method is now being applied worldwide in an effort to reduce cement production, hence the associated carbon dioxide emissions. With the worldwide production of cement estimated to contribute 5-8% of global carbon dioxide emissions, finding replacement materials has been seen as of significant importance in the industry.
In addition to improving the carbon footprint of the final concrete product, the use of GGBS and PFA has provided further benefits: they are normally cheaper than cement and their properties can improve the quality of the concrete product.
“The usage of these materials has enhanced the strength and durability parameters and improved the quality of concrete,” reports the Lootah Group spokesperson. “It also reduces the heat of hydration, that is the heat evolved during the reaction between cement and water,” the spokesperson adds.
In addition to meeting worldwide demands for improved environmental attributes, the changes are being introduced to meet consultant specifications for the durability parameters of concrete and to reduce the heat of hydration in concrete in deep foundations.
Some changes have been necessary to enable the use of the new materials, being facilitated by concrete producers.
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