2019 Highly Commended - Hawley Wharf, London

Concrete @ your Fingertips

Full list of Nuggets

Re-alkalisation of concrete.

The objective of re-alkalisation is to restore the alkalinity in carbonated concrete and to re-establish a passive environment around the reinforcement with the minimum of disruption to the concrete. The system involves passing an electrical current through the concrete to the reinforcement using an externally applied anode that is attached to the concrete’s surface. An outline of electrochemical re-alkalisation is shown in the Figure.

The system tackles the problem of carbonation without the need to remove contaminated concrete and, taking the cost of alternative ‘repair’ operations into account, can be cost effective. Tests for carbonation should be undertaken before and after re-alkalisation to determine the effectiveness of the treatment.

Re-alkalisation is covered by CEN/TS 14038, Electrochemical realkalization and chloride extraction treatments for reinforced concrete, Part 1: Realkalization.

Schematic of re-alkalisation process

Acknowledgement: The Concrete Society

Concrete Bookshop - Members receive 40% discount on Concrete Society publications

Guide to evaluation and repair of concrete structures in the arabian peninsula

Concrete repair manual