Researchers at the University of British Columbia (UBC) have developed a new seismic-resistant, fibre-reinforced concrete that can dramatically enhance the earthquake resistance of a seismically vulnerable structure.
Called EDCC (eco-friendly ductile cementitious composite), the material is engineered at the molecular level to react similarly to steel – with high strength, ductility and malleability. When sprayed onto the surface of traditionally poured interior concrete walls, it reinforces against seismic intensities as high as the magnitude 9.0-9.1 earthquake that hit Tohoku, Japan in 2011.
“We sprayed a number of walls with a 10 millimetre-thick layer of EDCC, which is sufficient to reinforce most interior walls against seismic shocks,” says Salman Soleimani-Dashtaki, a PhD candidate in the department of civil engineering at UBC. “Then we subjected them to Tohoku-level quakes and other types and intensities of earthquakes — and we couldn’t break them.”
In an earthquake concrete usually cracks and then crumbles — the EDCC helps to hold the concrete together, keeping walls and buildings intact.
Not only does it perform well seismically, the material also uses little cement. EDCC combines cement with polymer-based fibres, flyash and other industrial additives, making it highly sustainable, according to UBC civil engineering professor Nemy Banthia, who supervised the work.
“By replacing nearly 70 per cent of cement with flyash, an industrial byproduct, we can reduce the amount of cement used,” said Banthia. “This is quite an urgent requirement as one tonne of cement production releases almost a tonne of carbon dioxide into the atmosphere, and the cement industry produces close to seven per cent of global greenhouse gas emissions.”
EDCC has been added as an official retrofit option in B.C’s seismic retrofit program, where high risk schools are undergoing upgrades. The material will see its first real-life application this fall as part of the seismic retrofit of the Dr. Annie B. Jamieson Elementary School in Vancouver as well as an elementary school in Roorkee, Uttarakhand, a highly earthquake-prone area in northern India.
“This UBC-developed technology has far-reaching impact and could save the lives of not only British Columbians, but citizens throughout the world,” said Advanced Education, Skills and Training Minister Melanie Mark. “The earthquake-resistant concrete is a great example of how applied research at our public universities is developing the next generation of agents of change.”
Able to be applied to a variety of concrete structures, the researchers also anticipate use in the construction of pipelines, pavements, offshore platforms, blast-resistant structures, and industrial floors.
The research was funded by the UBC-hosted Canada-India Research Centre of Excellence IC-IMPACTS, which promotes research collaboration between Canada and India.
“This technology is gaining significant attention in India and will provide our Canadian companies a strong competitive edge in the growing global infrastructure market,” added Banthia, who also serves as IC-IMPACTS scientific director.