http://www.guardian.co.uk/environment/2008/dec/31/cement-carbon-emissions

anybody heard about this ?

"Novacem's cement, based on magnesium silicates, not only requires much less heating, it also absorbs large amounts of CO2 as it hardens, making it carbon negative."

"According to Novacem, its product can absorb, over its lifecycle, around 0.6 tonnes of CO2 per tonne of cement. This compares to carbon emissions of about 0.4 tonnes per of standard cement. "From that point of view, it's attractive," said Rachael Nutter, head of business incubators at the Carbon Trust."

"A spokesperson for the British Cement Association expressed a sceptical note, saying that though there was much ongoing laboratory work on new types of cement, there were also problems. "The reality is that the geological availability, and global distribution, of suitable natural resources, coupled with the extensive validation needed to confirm fitness-for-purpose, make it highly unlikely that these cements will a be realistic alternative for volume building."

Vlasopoulos responded that magnesium silicates are abundant worldwide, with 10,000 billion tonnes available, according to some estimates. "In addition, the production process of our cement is of a chemical nature, which means it can also utilise various industrial byproducts containing magnesium in its composition." He is confident the material will be strong enough for use in buildings but acknowledged that getting licenses to use it will take several years of testing"

sounds interesting , but I guess one expected answer here would be we should just use lime

cheers Jim

good to see you're on form.

whats the best alternative to concrete footings ?

<blockquote><cite>Posted By: jamesingram</cite>whats the best alternative to concrete footings ?</blockquote>

Timber posts? Stonework? Steel posts?

If its as good as they say it is then it will vastlty reduce energy used in the Building sector - this can only be a good thing.

Since it has the support of the Carbon Trust it doesn't seem tp be a snake oil type product. Good luck to them I say.

trule , yes something like the seagul post and beam method make good sense to me , but does it suit the UK
Using techniques that reduce footing size have got to be good, I'm just not that familiar with them
I'd like to get more experience/info in that area and see if I can use them in small scale extensions/jobbing work I do

If this product does come through testing etc. it sound a very positive substitute to OPC
no doubt it will have some negatives to be looked into.

This is interesting! Are these the same manufacturers from Bridgend? From my point of view cement should only be seen as a useful liquid solid that achieves our build speeds. if that can be used in conjunction with carbon absorption, then all could be satisfied? I, by the way, am a 25 year lime putty - nutter! There is so much we can do with the stuff. An interesting point too - I think that Co2 is already in the lime once mixed and that it is the removal of moisture that allows it to set, slower within the material than the surface, obviously.

http://www.novacem.com/index.php

doesn't look like coming to a Jewson's or TP near you any time soon...

J

Posted By: jamesingramdont these all require some sort of pad to sit on ?

I saw on the web, can't find it now, a US system where you stand a heavy cardboard tube, 2ft 3ft whatever diam on the ground, suck out the soil within it by truck-mounted vacuum/hose, so the cardboard 'caisson' sinks into the ground down to required found depth or to stronger subsoil; then fill the void with either concrete or - interestingly - well compacted aggregate. In the latter case, as the compacted aggregate is separated from equally compacted undisturbed subsoil by only the cardboard thickness (which rots away), it stays in shape as a column of strong loadbearing material inserted into the surrounding weaker soil. Tho I imagine if the surrounding soil was shifting sand or runny clay it might 'give' and allow the aggregate column to expand thus collapse in height.

Fencing contractors think nothing of sinking a 200x200 oak gate post 4ft into the ground, in minutes. Why can't same be done for piled founds?

Posted By: James Norton
Biff,
Underground retaining structures...
J

Yeah, maybe we shouldn't go underground too much, but vaulted brick ceilings can be very impressive.

"I saw on the web, can't find it now, a US system where you stand a heavy cardboard tube, 2ft 3ft whatever diam on the ground, suck out the soil within it by truck-mounted vacuum/hose, so the cardboard 'caisson' sinks into the ground down to required found depth or to stronger subsoil; then fill the void with either concrete or - interestingly - well compacted aggregate. " sounds interesting
I've been involved in some piling in domestic situation and seen something similar though not a vacuum/hose
just a core bit and cardboard liner put in as the bit goes down to the required depth . once reached they put in steels to tie in the slab formwork and fill with concrete. compacted aggregate sounds good though.
worked on several old houses where the splayed wall footing 2-3' deep just sat on a layer of compacted chalk
unfortunatly these were all subsidence jobs and we ended up building a retro fitted piled concrete mega slab to stop the subsidence, which i always thought was a bit OTT.