CROSSRAIL London Underground Elizabeth line – various London sites

Various Applications of foam concrete varying from mass infill of shafts and addits, to temporary infill work for TBM pass through and even burial of tunnelling machines at end of life. Over the course of 5 years, Propump have placed over 36,000 cubic metres of foam concrete, on some projects material was placed in double shifts and exceeded 600 m3 per day. Propump filled temporary access tunnels, buried 2 boring machines, and filled an old station platform. Propump have also filled 4 individual shafts used to deliver and transport equipment.

Stepney Green – TBM launch Addits – Jan 2013

Temporary Mass Infill material. Propump provided 1,500m3 to fill “addits”. These short tunnels had already been excavated and lined, Foam concrete was then used an a filling material to fill these “addits back up”. the designed application of foam concrete was to provide the TBM with a medium that was easy to excavate but would not collapse around the face of the TBM cutter, this enabled it to gain traction as it began its journey.

Dean Street Western Ticket Hall – Tottenham Court Road “running tunnel” – July 2013

Temporary Mass Infill material. This foam concrete infill involved pouring some 3,500 cubic metres over a course of days placing over 300 m3 per shift. Once complete the TBM began to pass through the layers of foam concrete before the top layer was 24 hours old. The station had already been excavated. It was more time and cost effective to place foam concrete into the excavation than it was to have the tunnel boring machine breach on one side, and then have to be dismantled and re assembled and then begin to cut into the opposite side of the station excavation.

Dean Street Western Ticket Hall – Tottenham Court Road – “wraparound” May 2013 3,600m3

In late May and early June 2013, Propump placed over 3,600m3 of foam concrete to fill some of the adjacent linking tunnels. at over 9 metres in diameter and 40 metres long, Our P595 foam concrete with a 28 day strength of 2-3N was specified to mass fill several short linking tunnels around the network of stations. Some of these tunnels were created for plant storage, traffic management or simple ease of access. Now the sections were surplus to requirements and required to be permanently abandoned.

Hannover Square Ticket halls – Bond Street Station – Shaft and access tunnels – June 2013 4,500m3

Hannover Square is the location for the new Bond street eastern ticket hall, once initial construction had finished, the bottom level and access tunnels needed to be filled, this “shaft” was the bottom level with several joining tunnels that had previously been filled. foam concrete is often specified for mass infill applications such as this because it is easy to get material down and into the void, it has a an expansion on site, reducing deliveries. and its major attribute is that it can be poured in 1 metre layers without compaction.

Fall Lane Bridge, East Ardsley, Wakefield.

Mass void foam concrete infill, 500kg/m3 density material used to strengthen a weak bridge by infilling between the spans, a secondary material 3N/mm2 foam concrete was placed for the last 500mm lift to the underside of the bridge deck. the light weight material was placed in 500mm layers from the floor up to the underside of the road deck, leaving only the one span open for the railway lines to continue.