Over the past year, there has been one story that has dominated the construction sector, and that is the concrete repair work being undertaken in response to concerns surrounding reinforced autoclaved aerated concrete (RAAC).
The concerns about RAAC, which were brought to widespread public attention in 2023, had been raised since 1995 at the very latest, but despite calls for greater scrutiny and its potential replacement, it took until the sudden and potentially life-threatening collapse of RAAC roofing tiles to spur action.
This somewhat mirrors the delays in the implementation of a repair programme for concrete roads and whilst the formulation of the concrete components are different, there are parallels that can be found between the two sets of work being delayed.
Part of it is that, especially in the case of RAAC, concrete tends to be exceptionally strong, robust and capable right up until the moment that it isn’t.
What concerned structural engineers in 1995 and led to remedial work from 2023 onwards was that there were serious issues with structural integrity that are not always readily obvious or apparent, owing to the nature of the bubbled texture of RAAC.
Much like how concrete roads seemed to survive so long whilst requiring slight repair or nothing at all, RAAC looked structurally sound years or even decades after the material was beyond its operating life, right up until the point where it fell apart.
RAAC has a typical lifespan of 30 years, lower than other forms of concrete, but there is a tendency to put off remedial work if there are no obvious issues, something that can cause a significant risk of sudden structural collapse.
A focus on proactive inspection and remedial rather than reactive and quick fixes will help reduce the risks to buildings and their inhabitants and save money in the long run.