Bligh Tanner, Wagners & HASSELL’s suspended geopolymer concrete floor panels have come out on top at the 2013 BPN Sustainability Awards, winning both the Innovation of the Year category, as well as the top accolade of the night, the Best of the Best Award.
The University of Queensland’s Global Change Institute (GCI), designed by HASSELL in collaboration with Bligh Tanner, Arup and Medland Metropolis, is the first building in the world to utilise such cement-free concrete for suspended construction.
The 33 precast floor beams in the new GCI building are made from Earth Friendly Concrete (EFC), a Wagners brand name for their commercial form of geopolymer concrete.
Comprising sand, aggregate and a binder that contains ground granulated blast furnace slag, a waste product from steel production, and fly ash, a waste product from coal fired power generation, EFC contains no normal Portland cement. This allows it to have very low CO2 emissions as compared to normal Portland cement-based concrete.
Up until this point, geopolymer has only ever been used in trials for ground bearing pavements, masonry blocks, and other low level structural applications.
However, through the process of verification testing in accordance with the performance specifications of AS3600 and full scale panel testing, this world-first use of modern geopolymer binders for suspended concrete construction in the building industry was enabled.
“We have taken environmentally sustainable design a step further and precast world-first geopolymer concrete floor panels which, with significantly lower embodied energy, helps to reduce the building’s carbon footprints,” said Bligh Tanner’s director, Rod Bligh.
“Prior to the GCI project, industry experts considered that practical application in such a significant way would be many years away from happening. We’re pleased our application expedited this for everyone’s benefit.”
Apart from being more environmentally friendly, the panels have faster curing times, which contribute to lowered production costs.
The different chemistry of the binder also means that the suspended geopolymer floor panels experience low shrinkage, low heat of reaction which avoids the possibility of thermal cracking, 30 per cent higher flexural tensile strength than normal concrete, and higher durability than normal concrete.
The innovative and pioneering use of geopolymer concrete on the project has been awarded two innovation points in the Green Building Council’s assessment for Greenstar rating, with the Institute itself a 6 star Green Star registered building.
“Standing head and shoulders above a crowd of very good entrants, it provides a long sought-after alternative to the highly embodied energy always associated with concrete,” commented the jury.
“This type of material innovation resolves base level problems before it even enters the building stage. Undeniably, the suspended geopolymer concrete floor panels will have massive applications across all sectors of the industry, with a great future in that direction.”