|
|
Post by philthetube on Sept 22, 2020 16:45:36 GMT
Despite the works extensive works done in the past few years, Concrete cancer has returned to the Uxbridge station roof with a small area fenced off by platform 4. (could be 1) and one or two other areas showing small signs of return.
Dose anyone know if this is just a small area with problems, or if the whole structure has real problems, possibly fatal.
|
|
|
|
Post by goldenarrow on Oct 27, 2020 17:55:39 GMT
It looks like it's isolated to the area above the buffers end of platform 4 which I believe has been cordoned off for at least a year now. From the photo I took today, it looks like its water ingress caused by poor run off drainage which has been a persistent issue in the past.  |
|
class411
Operations: Normal
Posts: 2,747 
|
Post by class411 on Oct 28, 2020 8:07:38 GMT
My knowledge of civil engineering is about nil, so take the following with a pinch of salt, but that does not look like water damage. Concrete is used for sea walls and has been used for roads and motorways so is not particularly susceptible to water damage from surface contact, provided it has been poured correctly and not suffered mechanical damage.
The section illustrated appears to have delaminated which would imply a faulty mixture that has cracked and allowed water ingress and possibly freezing which could break off chunks.
|
|
|
|
Post by t697 on Oct 28, 2020 11:27:14 GMT
I'm not a civil engineer either, but I think water ingress is a probable factor here. Also the reinforcing bars are very close to the original surface which is bad practice and can accelerate corrosion and spalling.
On a less serious structure one can recall the cast reinforced concrete fencing at Rayners Lane and Sudbury Town that had widespread failing like this and was completely renewed some years ago as part of retaining the heritage appearance.
|
|
|
|
Post by Chris W on Oct 28, 2020 22:07:30 GMT
From memory (28 years since I started by Building Surveying degree, graduating in 1995) this related to lime and steel reacting with water... causing cracking/weathering... This Australian WEBSITE, explains it very well... However it does miss one cause... time and building movement, which happens naturally.
Concrete by its very definition, is brittle and unable to flex, causing cracks... causing water ingress... causing a reaction with steel... causing expansion (freezing/thawing)... causing failure... Its simple cause and effect...
The challenge that LU faces, is how to maintain services, whilst urgent maintenance works (that needs funding which isn't there) are required...
|
|
|
|
Post by zbang on Oct 28, 2020 22:57:46 GMT
BTW, this is also known as "rebar rot", and yes, water ingress to uncoated rebar will do that.
|
|
