Concrete without cement, is that possible? Yes, Wolfgang Rieder firmly believes, and he has sent his company on a journey with "climate positive by 2030" as the destination. The gradual replacement of cement in the concrete matrix is just one of several ways of doing this. This is being trialled in practice at the new Rieder headquarters in Maishofen.
We have identified the levers where we can intervene in order to produce and operate CO2-neutrally by 2025. Now we are implementing our plan, evaluating the results and developing them further,” says Wolfgang Rieder, summarising the timetable of his company’s expedition towards climate neutrality. Innovation through new material combinations, digitalisation, the radical reduction of waste and the extension of the useful life of products and buildings are the driving forces in our transition to become a climate-positive company in eight years. Simply put, this means offsetting more CO2 than we emit. This is the only way to achieve the goals of the Paris Climate Agreement on climate change, namely to limit global warming to 1.5° above pre-industrial levels.
“Reuse and recycle”: glemm21 headquarters as the user case
One example of how globally necessary changes can succeed is glemm21, the new headquarters in Maishofen, which is not strictly speaking a new building. “Using what’s there already rather than building something new is known to be the best way to save grey energy and reduce land sealing. And so, we tried it out on ourselves”, says Wolfgang Rieder. A disused bus garage became the test laboratory for the greening of the globally active company, with further production sites in Kolbermoor (Germany) and Ladysmith (USA). The existing building was utilised and many other components were also reused or recycled. We used concrete columns from Rieder’s grandfather’s and father’s old factories, a previously produced massive concrete beam, 150 tons of recycled steel girders and much more. We even reused an old wall made of arolla pine wood that was dismantled elsewhere and helps create the pleasant ambience of a modern working environment. The principle of building in the existing fabric allowed Rieder to save around 1000 tons of CO2 compared with a new building, while at the same time turning a new building into a prime example of resource-efficient circular construction. The transformation process was supported by an engineering firm specialising in energy-efficient construction.
More eco-friendly friendly and durable
“The life cycle of buildings must increase”. This, according to Wolfgang Rieder, is a key factor for a more ecological construction industry that is economical at the same time. This can be achieved not only by converting and revitalising existing buildings, but also through more durable building materials. The model for this is the opus caementicium, the cast masonry used by the Romans. The Romans added pozzolana as a binder, which gave the material a durability that often exceeds that of modern concrete, as is illustrated by the Pantheon in Rome built at the beginning of the 2nd century. The cement used in the Rieder facade panels is gradually being replaced by natural pozzolana, which has significantly lower CO2 emissions during production. Inspired by ancestral knowledge and driven by the will to minimise the company’s ecological footprint and offer products that help bring about a climate reversal, Rieder developed a world first.
Leading the way: Rieder as the first manufacturer of low-carbon facades.
The glassfibre reinforced concrete elements with reduced cement content envelop the new Rieder headquarters on a facade area of 400 sqm. The slate texture in the colour pine green is reminiscent of slate. 50 percent of the cement in the concrete matrix was replaced by alternative materials, resulting in a CO2 reduction of 30 percent. The products concrete skin, öko skin and formparts with the CO2-reduced matrix are available in selected colours. The entire product range is to be converted to a cement-free material by 2027. The plan is to fully substitute the cement step by step. “We don’t just want to talk; for the ecological transition to succeed we need to take action,” says Wolfgang Rieder, reaffirming the course his company has been pursuing for several years. This makes Rieder the first manufacturer of low-carbon concrete facade panels. Cement-free concrete is just one piece of the puzzle in a company philosophy focused on overall sustainability.
