New concrete makes buildings earthquake-resistant
The material is engineered at the molecular scale to be strong, malleable, and ductile, similar to steel-capable of dramatically enhancing the earthquake resistance of a seismically vulnerable structure when applied as a thin coating on the surfaces.
Successful simulation tests
Researchers at the University of British Columbia in Vancouver, Canada, subjected the material, called eco-friendly ductile cementitious composite (EDCC), to earthquake simulation tests using intensities as high as the magnitude 9.0-9.1 earthquake that struck Tohoku, Japan in 2011. Their new development will see its first real-life application this fall as part of the seismic retrofit of a Vancouver elementary school.
10 millimetre-thick layer is enough
“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.” Other applications include pipelines, pavements, offshore platforms, blast-resistant structures, and industrial floors.
Cement with polymer-based fibres
EDCC combines cement with polymer-based fibres, flyash and other industrial additives, making it highly sustainable, according to UBC civil engineering professor Nemy Banthia. “By replacing nearly 70 per cent of cement with flyash, an industrial byproduct, we can reduce the amount of cement used,” he said. “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.”