The use of Reinforced Autoclaved Aerated Concrete (RAAC) in the construction of schools and hospitals in the UK is facing a major crisis, with experts warning that the material is at risk of collapse.
RAAC is a lightweight concrete made from cement, water, and an aluminium powder. It is cheaper and lighter than traditional concrete, making it a popular choice for construction projects. However, RAAC has a relatively short lifespan of around 30 years, and it can start to crumble and fail after this time.
In recent years, there have been a number of reports of RAAC concrete failing in schools and hospitals. In 2018, a school roof in Liverpool collapsed due to RAAC failure, and in 2022, a hospital in Manchester was evacuated after concerns were raised about the safety of the RAAC concrete in the building.
As a result of these incidents, the government has ordered the closure of more than 100 schools that have been found to have RAAC concrete. The closures have caused disruption to thousands of pupils and teachers, and have raised concerns about the safety of other buildings that may contain RAAC concrete.
The government has said that it will provide funding to repair or replace the affected buildings, but it is not clear how long this process will take. In the meantime, the RAAC concrete crisis is a major headache for the government and for the construction industry.
Experts say the scale of the problem is much bigger than schools
Professor Chris Goodier, of Loughborough University, said that the scale of the RAAC concrete problem is much bigger than just schools. “It also covers much of the building stock in the country,” he said.
“The government needs to urgently assess the risks and take action to ensure people are safe,” he added.
The RAAC concrete crisis is a major challenge for the government, and it is not clear how it will be resolved. However, it is clear that the problem is not going away anytime soon.
How was RAAC concrete made and used?
RAAC concrete was first developed in Austria in the early 1900s. It was soon adopted by other European countries, and by the mid-20th century, it was being used in buildings all over the world. In the UK, RAAC concrete was used extensively in the construction of schools, hospitals, and other public buildings from the mid-1950s to the mid-1980s.
RAAC concrete was attractive to builders for a number of reasons. It is lightweight and easy to handle, which makes it ideal for roofs and other overhead structures. It is also relatively inexpensive, and it has good insulating properties, which can help to reduce energy costs.
Why is RAAC concrete being replaced?
RAAC concrete has a relatively short lifespan of around 30 years. As a result, many of the buildings that were constructed with RAAC concrete in the mid-20th century are now reaching the end of their useful life. In addition, RAAC concrete can be susceptible to moisture damage, which can lead to cracking and spalling.
As a result of these problems, RAAC concrete is being replaced in many buildings. In the UK, the Department for Education has launched a program to survey and assess all schools that were constructed with RAAC concrete. The roofs of schools that are found to be at risk of failure will be replaced with other materials, such as steel or concrete.
What are the alternatives to RAAC concrete?
There are a number of alternatives to RAAC concrete that can be used in building construction. These include:
- Steel: Steel is a strong and durable material that is often used in the construction of roofs and other structural elements.
- Concrete: Concrete is a heavier material than RAAC concrete, but it is also more durable.
- Timber: Timber is a renewable material used to construct lightweight roofs and other structures.
- Composite materials: Composite materials are made from a combination of different materials, such as glass fibres and resins. They can be used to create lightweight, strong structures resistant to moisture damage.
The choice of material will depend on the specific requirements of the building project. However, it is important to note that all materials have their own advantages and disadvantages. It is important to select a material that is appropriate for the climate and the intended use of the building.
