High strength concrete with Elkem Microsilica®
Elkem Microsilica® is used to make the high-strength concrete that is essential for constructing the world's tallest buildings, such as the record-breaking Burj Khalifa in Dubai.
In this application, Elkem Microsilica® is used as a cost-effective means to increase the compressive strength of the concrete mix. Increased concrete strength is a result of microsilica's unique particle packing ability, combined with a pozzolanic reaction.
Burj Khalifa, world's tallest building – Case study
At 828 metres, the Burj Khalifa is the world's tallest building. Named after Sheik Khalifa bin Zayed al-Nahyan, it was officially opened in January 2010.
A range of high performance concrete mixes containing Elkem Microsilica® were developed, for piling and superstructure. For the concrete mixes, triple blends of binder were specified, comprising Portland Cement (low C3A) + Fly Ash + Elkem Microsilica®.
A triple blend approach to concrete mix design enables optimum high strength and high durability to be achieved.
For the Burj Khalifa, high strength concrete is required due to the massive dead weight of the building.
The triple blend mixes also provide the high durability which is necessary due to a harsh local climate, with high chloride and high sulfate ground conditions - conditions which would otherwise cause rapid deterioration of conventional concrete.
World record vertical pumping height
The Burj Khalifa project set a world record for pumping concrete in November 2007. An 80 MPa concrete mix, containing Elkem Microsilica®, was pumped from ground level to a vertical height of 601 metres. The high-strength pumped concrete was used to construct reinforced corewalls.
For more information about the use of Elkem Microsilica® in the Burj Khalifa project, and for general advice about high strength concrete mix design, including optimising particle packing.