On Fri, 04 Sep 2009 08:52:14 GMT, "Richard J."
wrote:

Basil Jet wrote on 04 September
2009 02:41:35 ...
What's this effect called?

http://maps.google.co.uk/maps?hl=en&...8. 15,,3,4.76

http://maps.google.co.uk/maps?hl=en&...,200.99,,3,2.6

I think London would look better if concrete structures such as the
Hammersmith flyover used this effect, but I don't know how expensive it
would be.

I think the Hammersmith Flyover is one of the best looking concrete
viaducts, and wouldn't be improved by that sort of treatment (and I
don't know what it's called).

http://maps.google.co.uk/maps?hl=en&...59.958801&z=15


The effect in Basil Jet's linked images is called "stucco" and it is a
style of rendering, not a concrete finish. Nowadays stucco is formed
in cement render, but it was formerly done in lime render. It was
very extensively used in London to give cheaply-built brick and rubble
structures the external appearance of masonry. Much of London's
stucco incorporated horse hair to give it greater resistance to
cracking. Some modern cement renders include artificial fibres for
the same reason.

http://en.wikipedia.org/wiki/Stucco

It is difficult, although not impossible, to finish concrete in this
way. You need specialist foam rubber moulds which do not come cheap
and you don't get many uses out of them before they break. Indeed, a
high proportion of foam rubber moulds have to be scrapped after their
first use, as it is difficult to strip them cleanly from the formed
concrete. This makes for a very expensive finish.

The Hammersmith Flyover was one of the first viaducts in the UK to be
built using a precast, pre-stressed post-tensioned reinforced concrete
balanced cantilever method of construction. The prominent lines are
at the location of the joints between the concrete sections of bridge
superstructure. In order to avoid the appearance of uneven joints,
the designer wisely decided to make a feature of them.

http://en.wikipedia.org/wiki/Hammersmith_Flyover