I recently attended the kick-off meeting for a really interesting and challenging project. Mott MacDonald are working with Transport for London to help them develop a specification for concrete for their track repairs.
“Bread and butter to you”, I hear you thinking; but just a minute I’ve not told you everything yet. The concrete is being used as part of a Mechanised Renewal Vehicle process and needs to be batched in the depths of the London Underground network. It needs to be quality controlled, accurately batched, tested, placed, finished and one small final point……
make 15MPa strength at 1 hour.
If it doesn’t, a significant number of the up to 5 million journeys made each day on the London Underground network will be disrupted.
Typically, the workforce in the Track Delivery Units (TDU) need to get on site, smash out the concrete currently holding in the rails, clear up the rubble, fix the rails in place and then pour up to 9 cubic metres of this fast strength gain concrete. Quite a challenge in the small overnight engineering windows available on the network. To make the project even more challenging, wouldn’t it be great to reuse the concrete broken out as aggregate in that days, or probably more realistically, a future concrete pour.
I’ll let you know how the work progresses but if any material suppliers out there have any products they would like me to consider, then please do not hesitate to contact me through this blog or look me up on LinkedIn.