RAAC stands for Reinforced Autoclaved Aerated Concrete. It is a lightweight form of concrete that was commonly used in building construction, especially in flat roofing, floors, and walls, mainly from the 1950s to the 1990s
. This material is characterized by its aerated, bubbly structure, which makes it lighter and easier to install than traditional concrete but also less durable, with an estimated lifespan of about 30 years
. RAAC consists of cement, lime, water, sand, and aluminum filings, reinforced with small-diameter steel rebars
. Its porous nature means it can absorb moisture, which can lead to corrosion of the reinforcing steel and potential structural failure
. RAAC was favored for its cost-effectiveness, ease of installation, and good thermal properties, making it popular in public sector buildings such as schools and hospitals during its period of use
. However, concerns have grown about its long-term safety due to its limited durability and susceptibility to moisture-related damage.
