An apartment building in Southampton was evacuated after concrete that was prone to collapse was discovered.

Reinforced autoclaved aerated concrete, known as RAAC, was discovered at Alyne House on North Road, forcing the landlord to evict the residents. Residents were notified in the second week of December last year.

Les Echos understands that only a few people still live in the neighborhood. "Many residents have moved out, and we would like to thank them for their calm response in difficult circumstances." RAAC was used in construction in the UK from the 1950s to the mid-1990s because it was cheaper, faster, and easier to install than traditional concrete. However, it collapses easily when wet and has a life expectancy of only 30 years.

Steve Leggett is the city councilor for Bannister and Polygon, where the neighborhood is located. He told the Echo: "I was delighted to hear that the landlord had responded quickly. "We visit Alyne House regularly as part of our canvassing program, but after our last visit, there was no one living there. Contact us with questions. "We are concerned that residents are having to cope with this disruption due to the state of this privately run block. If residents of Alyne House seek our support on this or any other issue, they are welcome to contact one of the three borough councilors anyone."

Hounsdown School in Totton was one of the public buildings identified as having RAAC when news broke last year that it was at risk of collapse. The Daily Telegraph reported that in September 2023, cracked RAAC boards were found in an apartment in Southampton. The exact location of the condo was not disclosed at the time, and it was unclear whether Alyne House was in the same neighborhood as the one reported by The Daily Telegraph.

A spokesman for Southampton City Council also shared some advice. They said: "Southampton residents can find housing information on our website or contact us directly with any questions."

What causes cracks in concrete?

Construction technology issues: During the structural construction process, various forms of cracks may occur due to unreasonable construction technology. For example, if the formwork has insufficient stiffness, when concrete is poured, the formwork will deform due to lateral pressure, resulting in cracks consistent with the deformation of the formwork. If the formwork is removed too early during construction, the strength of the concrete will be insufficient, causing cracks to occur in the component under its own weight or construction load.

Concrete material issues: Concrete is mainly composed of cement, sand, aggregate, mixing water, and admixtures. Substandard quality of materials used in concrete may lead to cracks in the structure. For example, suppose the mud content of sand and gravel exceeds the regulations. In that case, it will not only reduce the strength and impermeability of the concrete but also cause irregular network cracks when the concrete dries.

Shrinkage problem: During the drying process of concrete, cracks may occur in different parts due to volume shrinkage. Plastic shrinkage cracks mostly appear on the surface of structures and components that are newly poured and exposed to the air. They vary in length and are incoherent, similar to dry mud surfaces. Most of them occur after the initial setting of the concrete (usually about 4 hours after pouring) when the outside temperature is high, the wind speed is high, and the climate is arid.

Environmental factors: Changes in the external environment, such as temperature and humidity, may also cause concrete to crack. For example, increasing the amount of water and cement, or a sizeable water-cement ratio, results in increased shrinkage when the concrete sets and hardens, and irregular cracks appear on the concrete surface; or increasing the amount of water and cement, or a sizeable water-cement ratio, causes irregular cracks to appear on the concrete surface.

Foundation settlement:

· The foundation settles.

· The support stiffness is insufficient.

· The load preloading is not carried out as required.

· The preloading load is inadequate.

After the concrete is poured, the support sinks unevenly, causing cracks in the concrete.

Why use concrete anti-cracking agents in construction

Improve the crack resistance and toughness of concrete: Concrete anti-cracking agents can fill the micro-cracks and voids in concrete, increase the crack resistance and toughness of concrete, and effectively reduce the brittleness of concrete, making it less likely to crack during stress.

Enhance the durability of concrete: Concrete anti-cracking agents can improve the impermeability properties of concrete and reduce the intrusion of moisture and harmful substances, thereby improving the durability of concrete.

Reduce the shrinkage rate of concrete: Concrete anti-cracking agents can reduce the shrinkage rate of concrete, reduce the volume change during concrete solidification, and prevent concrete from cracking.

Improve the strength and load-bearing capacity of concrete: Concrete anti-cracking agents can effectively improve the stability and load-bearing capacity of concrete, thereby enhancing its compression resistance and durability.

Improve the appearance quality of concrete: Concrete anti-cracking agents can make the concrete surface denser and reduce pores and cracks on the concrete surface, thereby improving the appearance quality of concrete.

Supplier

TRUNNANO is a supplier of concrete anti-crack agent(which is one of concrete additives) with over 12 years experience in nano-building energy conservation and nanotechnology development. It accepts payment via Credit Card, T/T, West Union and Paypal. Trunnano will ship the goods to customers overseas through FedEx, DHL, by air, or by sea. If you are looking for high quality concrete additives, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com).