Analysis

Lightweight Champion

Lytag FZE managing director Andy Doel says choosing secondary lightweight aggregate for large-scale projects is essential to delivering on impressive designs, gaining sustainability credentials and cutting costs

Construction projects in the Middle East are on a grander scale than ever before, a trend that looks set to continue.
The iconic and high-profile Burj Khalifa is not long finished; September saw the contract award for the Kingdom Tower in Jeddah; ground has been broken on the 25-year Heart of Sharjah regeneration scheme; and the huge programme to expand Dubai International Airport continues.
It is not only in creating tall buildings and delivering iconic designs that construction in the GCC is world leading; protecting the environment has also risen to the top of the agenda.
Action has been fuelled in no small part by legislation and targets set by governments across the region, as well as by demand from customers and industry. This has been facilitated by ever-growing knowledge and expertise within the industry.
But how can clients, design teams and contractors work together to achieve excellent sustainability credentials while meeting the design and engineering challenges of major projects, alongside those posed by the turbulent global economy?

Materials matter
As such a widely-used and versatile material, the choice of concrete can have a considerable impact on all these areas of a project. For example, using a secondary lightweight aggregate (LWA) can help engineers overcome the challenges posed by concrete’s usual weight.
This is because structural concrete manufactured using LWA is 25% lighter than traditional concrete, but with the same structural integrity.
Using a lightweight concrete allows spaces to be designed with larger structures and greater spans, and a reduced number and width of columns which ultimately provides building
owners and occupiers with maximised usable floor space and increased commercial value.
Reinforcement and support work can also be reduced, leading to a considerable cost saving in terms of materials and labour. And importantly, using secondary aggregate reduces demand on quarried resources and diverts material that may otherwise be sent to landfill as waste.

Case study
The expansion of Dubai International Airport offers a good demonstration of this in practice. The airport first opened in 1960 and it has been developed considerably over the past 50 years.
A new expansion master plan was launched in 1997, and expansion works continue on Terminal 3 which include the construction of the new Concourse 3, expected to open in late 2011.
The need for space is paramount in any airport design, as are high-quality, strength and durability in its realisation. Marrying these is a challenge for any airport construction or expansion project, and for the expansion of Terminal 3, building the concourse floors posed an engineering problem. Traditional concrete would weigh too much for the demands of
the terminal’s design and its load-bearing properties.
With the support columns that would be necessary, the usable floor space in the lower ground floor areas would be reduced.
As a solution, main contractor Al Naboodah Contracting and concrete supplier CEMEX UAE chose to use concrete made with LYTAG LWA in the floor slabs for the concourse areas. LYTAG LWA was used to create 10,000m³ of lightweight concrete in a project that commenced in March 2010 and is expected to be completed in early November 2010.
The reduced weight of the concrete floor slabs for the concourse at Terminal 3 has reduced deadload, and is enabling the floor space in the lower ground areas to be maximised.
Using LWA has allowed CEMEX UAE to provide a ready-made, effective solution to a significant design and engineering challenge faced by the project team.
This lightweight aggregate is a unique, high-quality material and its use has mitigated any quality issues that may otherwise have been experienced.
This was crucial on a project such as this where achieving the highest quality is of primary concern.

Sustainable savings
At a time when budgets continue to be tight across the globe, using LWA also enabled the client to make cost savings on the main structure because extra support work and the associated material and labour costs have been avoided.
In addition, reducing environmental impact is an important aspect of this project and the use of
LWA makes a significant contribution, enabling the project team to secure LEED credits for incorporating a sustainable material into production.
As this project shows, using the right concrete can enable the delivery of impressive design and sustainability credentials on large-scale projects, and can even offer cost savings.
The construction industry will no doubt play an important role in shaping the future of the region, and all involved are presented with both an opportunity and responsibility to
maintain commitment to sustainable working, quality engineering and iconic design.

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