Crumbling concrete

[edit] What is crumbling concrete ?

Crumbling concrete describes failure where concrete parts are filling off in chunks and the strength of the overall material is compromised. It can simply be the result of ageing but maybe worsened where the initial pour was not managed correctly, where reinforcement elements are beginning to corrode or where the material is exposed to harsh elements or mechanical damage.

In December 2022 the UK Government published 'Reinforced autoclaved aerated concrete (RAAC): estates guidance'. The guidance set out a 5-stage approach to the identification and management of RAAC in educational buildings, where these maybe present in floors, walls and roofs (pitched and flat) of buildings constructed or modified between the 1950s and mid-1990s. This guidance outlined initial steps that should be taken by those responsible for the management of educational buildings, how to procure building professional’s services when specialist advice is needed. It was designed for all parties involved in the identification and management of RAAC, including estates managers and those providing specialist advice, can use this guidance.

In mid 2023 UK ministers Ministers launched a UK government-wide inquiry into the use of crumbling concrete, in particular occurring in reinforced autoclaved aerated concrete (RAAC). Initial indication is that many of the installations at risk are over 30 years old which may be beyond the expected lifespan of the product. Typically these are low-rise flat roofed structures built between mid-1960s and mid-1990s primarily of RAAC blocks.

[edit] Related articles on Designing Buildings

• Admixtures in concrete.
• Alkali-activated binder.
• Alkali-aggregate reaction (AAR).
• Alkali-silica reaction (ASR).
• Cellular concrete.
• Concrete masonry unit CMU.
• Concrete superplasticizer.
• Defective Concrete Blocks Grant Scheme.
• Rebar.
• Recycled concrete aggregate RCA.
• Reinforced concrete.
• Spalling concrete.
• Stratification of concrete.
• The properties of concrete.
• The use of concrete structures to protect construction sites.
• Types of concrete.
• Ultra high performance fibre concrete.
• Vibration Compaction Technology.
• What will happen if we use too much rebar in concrete?

[edit] External links

https://www.gov.uk/government/publications/reinforced-autoclaved-aerated-concrete-estates-guidance