Overcoming hydrostatic pressure in Central London | LKAB Minerals
High density concrete pour to overcome hydrostatic pressure, london

During 2017, LKAB Minerals supplied 400 tonnes of MagnaDense to the Kilburn project in North West London for a residential and commercial construction project, replacing five old buildings with new.

The project involved 120 cubic metres of high density concrete to prevent hydrostatic uplift of the sewer network below.

Preventing hydrostatic uplift

High density concrete produced using the aggregate MagnaDense, acted as a weight creating a stable base above an existing sewer running directly below the construction site. The dense concrete was placed above the sewer, preventing the historic pipework from lifting due to hydrostatic pressure. This would not only be detrimental to the sewer but would also create costly and time-consuming delays caused by moving or adapting the sewer network.

Concrete design

The concrete required a specific strength and density but also needed to meet the required flow for the project. We supplied a combination of MagnaDense 20s, 8s and 2 for the project. The final concrete mix achieved a density of 3.8 tonnes per cubic metre and a strength of C32/40.

London Concrete, the concrete producer and installer for this project, has extensive experience of MagnaDense concrete. They have previously trialled and produced 4,000 tonnes for the Crossrail project. Because of this experience, they could adapt the mix to suit the application and meet the requirements of the project.

Kilburn residential project

The full project was completed in 2017. This involved the demolition of five buildings, ancillary garages and boundary walls to Kilburn High Road and Oxford Road to make way for five new buildings. These new buildings range from 2-9 storeys with a total of 195 dwellings. Additionally, the project involved the retention and restoration of the Tollgate building, which will create 53 new homes. As part of the project, London Concrete was also responsible for the construction of a community centre on Kilburn High Road, as well as the relevant changes to infrastructure, parking and landscaping.