Background
More than 600 concrete bridges in Denmark, together with numerous tunnels, dams, marine structures, and buildings worldwide, are affected by Alkali-Silica Reaction (ASR), one of the most severe long-term deterioration mechanisms in concrete structures. ASR causes cracking and expansion of the concrete, leading to concerns regarding structural safety, service life, and maintenance strategies. Despite decades of research on material degradation, substantial uncertainties remain regarding the actual load-carrying capacity of ASR-damaged reinforced concrete structures and how existing structures should be assessed and managed.
Current assessment methods often rely on conservative assumptions due to limited knowledge of how ASR affects key structural mechanisms, including shear transfer, bond between reinforcement and concrete, anchorage behaviour, and the capacity of structural members without shear reinforcement. These uncertainties can result in unnecessary strengthening measures or premature replacement of otherwise serviceable infrastructure.
Research Programme
REACT is a long-term research programme at the University of Southern Denmark aimed at improving the assessment, monitoring, and management of ASR-damaged reinforced concrete structures.
The programme combines large-scale experimental investigations, advanced structural monitoring, numerical modelling, and assessment methodologies to establish a sound scientific basis for evaluating the residual capacity of deteriorated infrastructure. The overall objective is to support more reliable and sustainable decisions regarding maintenance, strengthening, and replacement of concrete structures affected by ASR.
REACT brings together multiple projects from different funding bodies and includes partners such as researchers, infrastructure owners, consulting engineers, and industry partners to address challenges that are directly relevant to the management of ageing bridge infrastructure in Denmark and internationally.
Research Themes
The programme focuses on several fundamental structural mechanisms that govern the behaviour and capacity of reinforced concrete structures affected by ASR:
Bond and Anchorage in ASR-Damaged Concrete
An Industrial PhD project investigates how ASR influences the bond between reinforcement and concrete in slabs and shell structures without shear reinforcement. Bond deterioration directly affects force transfer, anchorage capacity, crack development, and structural robustness, yet remains one of the least understood aspects of ASR-damaged reinforced concrete. The project employs advanced Distributed Fibre Optic Sensing (FOS) and Digital Image Correlation (DIC) to obtain highly detailed measurements of strain distributions and failure mechanisms.
This Part of the programme is funded by COWIfonden and Innovation Fund Denmark.
Shear Capacity of ASR-Damaged Slab Bridges
A PhD project focuses on the shear capacity of reinforced concrete slab bridges deteriorated by ASR. Many existing bridge structures rely on concrete shear resistance rather than conventional shear reinforcement, making their assessment particularly challenging when ASR cracking is present. Through large-scale testing and analytical modelling, the project aims to quantify how ASR affects shear resistance and to develop improved assessment procedures for bridge owners and engineering practitioners.
This Part of the Project is funded by The Villum Foundation and is also a part of the CEBE Research Programme.
Structural Assessment and Decision Support
The programme investigates how experimental observations and monitoring data can be translated into practical tools for structural assessment. This includes the development of models and methodologies that can reduce uncertainty in capacity evaluations and support risk-informed infrastructure management.
Advanced Experimental Techniques
A key feature of REACT is the use of state-of-the-art monitoring technologies for reinforced concrete research. Distributed Fibre Optic Sensing enables continuous, high-resolution strain measurements directly within reinforcement bars, providing previously unavailable insight into internal force transfer mechanisms. Combined with Digital Image Correlation and large-scale laboratory testing, these technologies allow researchers to observe structural behaviour with unprecedented detail and improve the understanding of deterioration-induced failure mechanisms.