As temperatures fluctuate, concrete – as with many other materials – expands with heat and contracts with cold. This has implications for the utilisation of concrete as a building material and this issue is further exacerbated by the use of concrete in specific construction settings.
A concrete expansion joint – sometimes referred to as a ‘control joint’ – in simple terms allows for the expansion/contraction of a piece of concrete without the process affecting surrounding structure and/or leading to the cracking of the concrete itself.
They are commonly deployed where a structure has been formed by multiple concrete pours – for example concrete roadways or car park decks – and where concrete is bordered by other building materials as the extent to which other materials expand/contract can significantly differ from that of concrete leading to severe stresses, and in some case failure, of not only the concrete but also of the surrounding materials/structures.
Two common types of expansion joint are to ‘fill’ between areas of concrete – at specific intervals – with a flexible material (frequently a resin-based product, foam or fibreboard) that will flex as the concrete expands/contracts without separation occurring or to leave an open gap. The precise method used will depend upon many factors such as the purpose of the construction and the scale of the works (domestic patio or roadway bridge, for example); factors which also influence the material used.
Of course, over time the movement associated with expansion/contraction can lead to degradation of the concrete (and indeed to the ‘filler’ used in the gaps also) – even with the correct use of expansion joints – and is often found at the edges of the concrete.
At Integral Concrete Solutions, we are specialists in the repair and refurbishment of concrete surfaces and use a wide variety of techniques to resolve problems. Please get in touch with our team on 01902 674 894 and we’ll be happy to discuss, survey and propose a schedule of works for any concrete degradation issues you may have.