In the resource-intensive construction sector, factors such as corrosion protection and monitoring could help to extend the lifespan of structures – An insight into selected research projects at HTWK Leipzig
Structures such as bridges or buildings are usually designed to last for around 80 to 100 years. Regular, simple visual inspections enable obvious defects to be identified and subsequently rectified. On a larger scale, more extensive maintenance work is required, for example when the road surface needs to be resurfaced. However, the service life can also be extended if high-quality materials are used from the outset, the structure is designed to withstand the intended load, and maintenance is improved.
Corrosion protection against cracks
Cracks can significantly shorten the service life of structures. They allow water and pollutants to penetrate, which can cause the internal steel reinforcement to corrode. Repairs are labour-intensive and costly. This is particularly critical in the case of concrete floor slabs that rest directly on the subsoil: As the concrete hardens and cools, it shrinks. Because this deformation is restricted by friction against the subsoil, stresses build up within the structural element, which often lead to cracks. To absorb these stresses, in practice more reinforcing steel is usually incorporated than would be required for the load-bearing capacity.
As part of the ‘SlideTex’ project, funded by the Federal Ministry for Economic Affairs, researchers at HTWK Leipzig are working with partners to develop a textile sliding layer designed specifically for this purpose. It is laid between the subsoil and the concrete floor slab and significantly reduces friction. This allows the floor slab to deform more freely, reducing stresses and minimising the formation of cracks. Another advantage is that, due to the lower stresses, the amount of reinforcing steel required can also be reduced. This saves material, cuts costs and reduces greenhouse gas emissions. The researchers are currently testing the system on large-scale floor slabs under real-world conditions until summer 2026. “We want to investigate how it behaves in a real construction environment,” says Florian Junker from the Institute of Concrete Structures (IfB) at HTWK Leipzig. If this proves successful, they will be one step closer to widespread application. However, further research is needed, particularly into the long-term stability and recyclability of the textile materials.
Continuous monitoring
Targeted monitoring of structural components enables damage to be detected at an early stage and subsequently repaired. Guided by this principle, researchers at the IfB are currently developing a minimally invasive measurement system as part of the ‘pHalcon’ project to investigate the susceptibility of concrete reinforcement to corrosion. In doing so, they measure the pH value, chloride content, temperature and moisture levels. “Using this corrosion indicator, we can assess whether the hidden, internal reinforcement is corroding and whether maintenance measures are necessary to ensure that structures remain usable for as long as possible,” explains Dr Martin Weisbrich. He heads the ‘Sensors and Monitoring’ research group, which develops holistic solutions for condition monitoring of structures, components and building materials. The focus is on measurement challenges associated with cement-bound materials. Appropriate monitoring allows even the smallest defects to be detected at an early stage, meaning that maintenance can be carried out on an as-needed basis rather than at fixed intervals.
The research carried out by Volker Slowik, Professor of Structural Mechanics at HTWK Leipzig, also focuses on early-stage, needs-based maintenance. In the ‘smart_tendon’ project, funded by the Federal Ministry of Transport, he and his team have been investigating prestressed concrete bridges, focusing in particular on how their service life can be extended. In prestressed concrete bridges, the concrete is subjected to compressive forces by means of tensioned steel tendons, which enables the construction of bridge components with minimal cracking. To ensure the safety of prestressed concrete structures, they are monitored through regular visual inspections and the use of measurement technology. If, as in the project, spatially resolved strain sensors were attached to the tendons, data on the condition of the prestressed concrete bridges could be recorded throughout their entire service life. “This would allow any structural damage that may occur to be detected at an early stage and maintenance measures to be planned more efficiently, thereby extending the service life of bridges,” said Slowik.
Extending the service life of complex building structures
Using structural health monitoring concepts, researchers at the Institute for Statics, Structural Dynamics, System Identification and Simulation (I4S), led by Armin Lenzen, Professor of Structural Mechanics at HTWK Leipzig, aim to extend the service life of complex building structures. As part of the ‘Hundert Plus’ priority programme – which has been funded by the German Research Foundation (DFG) since 2017 and is now in its second phase – he and his team developed a method for the automatic detection of structural changes and the early detection of damage in buildings and facilities. The measurement method automatically generates digital models based on measured data. Using these models, together with sensors fitted to the structures, it is possible to carry out local as well as global – and, above all, continuous – monitoring of buildings and bridges. If measured values move into critical ranges, targeted on-site inspections can be carried out to determine whether damage is actually present and what measures are necessary. The method developed was successfully tested on two large-scale structures. In particular, this included a bridge approximately 400 metres long whilst in service, where the researchers were able to clearly localise structural changes. The findings obtained in this way could therefore help not only to analyse the condition of bridges more effectively and predict their service life, but also to plan maintenance and refurbishment measures in a more targeted and needs-based manner.
Note: This article first appeared in the research magazine *Einblicke 2026*.
