Concrete step barrier

[1] With effect from January 2005 and based primarily on safety grounds, the UK National Highways policy is that all new motorway schemes are to use high-containment concrete barriers in the central reserve.

All existing motorways will introduce concrete barriers into the central reserve as part of ongoing upgrades and through replacement when these systems have reached the end of their useful life.

[1] Government policy ensures that all future crash barriers in the UK will be made of concrete unless there are overriding circumstances.

Various types of aggregate may undergo chemical reactions in concrete, leading to damaging expansive phenomena.

Following the alkali-silica reaction (ASR), an expansive gel can form, that creates extensive cracks and damage on structural members.