Concrete Reuse

The reuse of concrete in new structures is a great way to achieve low carbon design. Beginning your design with an understanding of what is already available completely changes the process of design. One of the barriers, however, is knowing what is inside the concrete.

For excellent work in this area, please visit Corentin Fivet’s team at EPFL: https://www.epfl.ch/labs/sxl/

How we can retain information about rebar in new construction for future reuse is a question that comes up a lot. Digital storage is unlikely to be reliable enough to retain information for long enough periods of time - data is lost either through corruption, lack of interest, unwillingness to pay for storage, and all manner of other things. Just ask yourself - if you found a 20 year old Excel workbook, would you be able to open it? Probably not.

Over the course of MEICON, and in subsequent discussions, one idea came up as promising long term data storage – to etch onto the side of concrete components some information about their design. This could include concrete strength, reinforcement percentages, a bar schedule, or even a reinforcement drawing. Laser etching, particularly on the internal faces of components where the environmental conditions are generally very benign, is (in our opinion) a great way to retain information that will easily be lost if archived in paper or digital form.

The method of engraving/etching might vary depending on production method. Etching directly onto the concrete might be best suited in precast manufacture. For in-situ construction, you might etching onto a stainless steel plate, place this in your mould at the cast face, and ensure it is anchored into the concrete behind. Either way, a physical representation of the internal condition should be achieved.

The example given in the image below combines a reinforcement drawing with a QR code which could link to a digital file - if it is kept for long enough! Remember, we want our concrete structures to be in use and adapted over time to last >100 years. This is not a question of retaining information over the course of construction, but one of retaining information over the course of generations.