On Sat, 21 Jun 2008 07:45:12 -0700 (PDT), "
wrote:

We've been using red brick dust to get the colour (and its pozzolanic
effect) - but the proportion has been 25% (i.e 1 part lime putty, 3
parts sharp sand, 1 part brick dust).

Can anyone tell me more about the possible effects of using such a
large proportion of brick dust?

I dont think there has been any research into the use of pozzolans as
an additive to lime putty mortar, but in general it will make it
harder, more brittle and possibly less durable

I dont use pozzolans. If I want hydraulicity then I use a hydraulic
lime to get a more predictable effect. My clients expect me to get it
right first time :-)

Anna
--

~ ~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repair and conservation
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|_____ / www.kettlenet.co.uk