From Foundations to Water Management: Concrete in Data Centres

Concrete plays a role in numerous areas of data centre construction, from the structural framework to underground infrastructure. At the same time, issues surrounding CO₂ emissions, the circular economy and the responsible use of resources are becoming increasingly important. In this eco interview, Jens Franz from Finger Stockstadt GmbH & Co. KG explains the developments shaping this building material, the approaches available for reducing emissions and how rainwater management can also be made more intelligent.

What characterises the use of concrete in data centre construction, and what are the key considerations during planning and implementation?

The use of concrete in data centre construction offers unrivalled advantages when it comes to protecting highly sensitive IT infrastructure. Planning requires exceptional load-bearing capacity and protective functions, both for the above-ground structural framework and for critical components in civil engineering. A key feature in building construction is the material's exceptional load-bearing capacity: solid reinforced concrete can easily support the enormous loads imposed by server racks and cooling systems, which often exceed 1,500 kg/m² during operation. Furthermore, this construction method provides the highest level of physical security and, thanks to its high thermal mass, also helps to stabilise the indoor climate. In civil engineering, underground concrete cable ducts, shafts and pipelines protect energy, data and resource supplies, while retention basins and firewater tanks support water and emergency management.

The carbon footprint of buildings is increasingly being assessed across their entire life cycle. What options are there for reducing emissions from concrete components as early as the construction phase?

As a manufacturer of precast concrete elements, emissions (Scope 3) are a very important issue for us. In addition to optimising existing mix designs by adjusting individual components, there are currently opportunities to significantly reduce the carbon footprint. However, that was not enough for us, so with next.beton we developed a cement-free concrete. Components such as pipes and manhole bases have already been certified by the DIBt, and there are already projects in which these products are being used.

However, it is also important to consider what happens at the end of the life cycle, as these buildings are being constructed to last for decades. Where components remain permanently in the ground, concrete stands out for its mechanical and chemical stability, as well as its high load-bearing capacity, positional stability and durability. If the structure is eventually dismantled after several decades, concrete can be recycled in accordance with circular economy principles and reused, for example, as aggregate in road or building construction. New processes are also being tested that separate concrete back into its original constituent materials.

New materials and manufacturing processes can make concrete more climate-friendly. What role can cement-free concrete, low-carbon reinforcing steel and new construction methods play in this?

Applied to our components, we can already achieve substantial savings with today's technology if the customer wishes. This can be done by optimising mix designs in terms of their cement content, by using next.beton - which achieves savings of approximately 69 per cent for the concrete itself - and by using reinforcing steel from modern production facilities with verified CO₂ emissions of 400 to 600 kg/t, instead of approximately 1,500 kg CO₂/t from conventional production.

The cross-sections of components are always adapted to local conditions and technically optimised in consultation with the planning teams, naturally within the framework of applicable standards and legislation. With our development work, however, we deliberately aim to go beyond improvements in individual areas and instead design and manufacture our products as sustainably as possible. Ideally, they are deployed as an integrated solution with intelligent control systems, because this is where synergies become apparent and can be incorporated into the sustainability management of companies and local authorities.

In addition to the carbon footprint, water management is also becoming increasingly important for many sites. What opportunities do concrete structures offer for storing and using rainwater, and how can this potential be better harnessed through intelligent control systems?

Water is our most important resource. Thanks to their robustness and versatility, concrete structures play a central role in modern sponge-city infrastructure, as they make it possible to collect, store and use rainwater directly on site. The primary storage options include underground concrete cisterns and retention tanks, which, thanks to their high structural load-bearing capacity, can easily withstand vehicle traffic and are completely protected against buoyancy.

However, the full potential of these storage structures can only be realised through an intelligent, digitally connected control system such as calmar.one. Conventional cisterns are often already full and overflow when sudden heavy rainfall occurs - or they may already be empty. Our system links automated storage management with real-time weather forecasts, enabling it to release precisely the amount of water required to accommodate the expected volume of rainfall ahead of a storm. Sensors monitor the fill level and other parameters, while calmar.one controls dynamic retention fully automatically. Consumption data for the collected water is also analysed to ensure optimal use, meaning that the maximum possible amount of service water is always available.

If several concrete structures within a campus are also digitally interconnected, this creates an intelligent network that detects impending overloads and can flexibly redirect water to available capacity at neighbouring buildings or, for example, make it available to a local authority for watering a municipal park.

Sustainability must increasingly become measurable and comparable. What is the significance of reliable CO₂ data for concrete components, and how can it help clients and planners to specifically account for Scope 3 emissions in data centres and other buildings?

Planning consultancies and building owners encounter structural obstacles when seeking to reduce CO₂ emissions in practice, as theoretical best-practice concepts often prove difficult to implement because of supply-chain constraints or structural engineering requirements, or because access to the relevant manufacturers or contact persons is lacking. For us as a manufacturer, in turn, it is difficult to identify the right contacts at an early stage, as planning is often already well advanced by the time we become involved in the operational process, leaving only limited scope for adjustments.