ZBG Seestadt Aspern is a school project of unique size and structural complexity. From September 2028, the state-of-the-art education facility will provide space for up to 7,500 learners a year across a usable area spanning 42,000 m². The school is being built by PORR and joint venture partner Apleona. The scale of the project will see up to 400 people employed during the construction phase.

The project is also setting new standards in the use of low-emission concrete. On behalf of the City of Vienna, PORR is using the cement type CEM II/C as the primary binder for load-bearing structures. In combination with optimised transport routes, this enables particularly high CO₂e savings and demonstrates the climate protection potential inherent in concrete construction.

664 times around the equator

By the end of the project, around 36,000 m³ of this concrete will have been used in Aspern, thereby saving approximately 4,200 t CO₂e. PORR CEO Karl-Heinz Strauss makes this comparison: “4,200 t corresponds to the emissions generated by burning 1.6 m. litres of diesel. That is enough diesel to take your car around the equator 664 times. This illustrates how much existing savings potential there is when we take an intelligent approach to using low-emission building materials”.

Challenges posed by new mixes

PORR is working continuously on the advancement of CO₂e_-optimised concretes and on testing alternative concrete mixes. It is true that these may present technical challenges for construction companies but they are indispensable for reducing emissions in the construction industry. Specifically, some modified formulations can affect workability, for example by requiring longer curing times, which in turn place higher demands on production, transport, processing and post-treatment. In Aspern, however, this was not the case - that’s why the project provides especially valuable insights into the future application of the building material.

Shorter transport routes

Supply chains in the ZBG Seestadt Aspern project have also been geared towards reducing emissions. A mobile concrete plant reduces transport routes. Excavated material is processed at a gravel processing plant two kilometres away and then reused in concrete production. “The experience gained here in collaboration with the City of Vienna is highly promising and demonstrates that we have the opportunity to implement significant and effective climate protection measures in concrete construction”, said Strauss.