geo-polymer cement ? i dont think it viable to heat the poured cement for 1-2 days to 176F i want to use ICF also so really no
What about "recycled" concrete? They tear up sidewalks all the time in my town, and I've seen big chunks of cement used from these sites before for simple garden walls and paths ... I'd love to see how they hold up building something larger with more structural needs.
Philip Freddolino wrote:
place a perferated drainpipe at a gradual slope to daylight,
We are almost done digging the trench for our community house rubble trench foundation. But there is something we just don't understand....
What does "to daylight" mean? Our trench is sloping, but we just don't know exactly what to do with the perforated pipe. Does it go in around the trench in a closed loop? or do we have to dig an exit trench for the pipe?
velacreations wrote:I totally agree with Walter on these points. And as a side note, cement alternatives are available for your concrete (fly ash, roman cement, geopolymers, lime).
Pam wrote:it seems a bit extravagant to proclaim it as the answer to all problems.
Concrete technology has vastly improved since Roman days.
Pam wrote:What do you base that on
you might want to read this concerning the reason why people are concerned about cement. Not only is the manufacturing of cement the 3rd largest contributor to CO2 but the other emissions from its manufacture are considered directly or indirectly to cause a number of deaths each year, which I didn't know.
"The bit about concrete being so high energy/CO2 intensive is deceptive and a myth.
1) Cement is really what they're talking about, not concrete when they discuss the energy issue. Cement is the binder. Concrete is the mix = cement + stone."
3) Concrete lasts essentially forever. Cordwood, cob, strawbale, timber logs, post and beam, stick lumber have very short relative life spans. There are concrete structures that have been in place for thousands of years.
..... In the process architects are finding that other types of concrete binders are at the very least equally effective. There is some very strong evidence that geopolymer cements were used.....
Being someone who has worked with concrete for 22 years,I don't know where Walter gets the idea that concrete will last nearly forever.just look at any 20 year old bridge or all the cracked,spalding and even rotting walks and foundations-I have repaired many and if there's steel in there it will eventually rust and pop the concrete.It's a common problem in concrete window sills.A problem that we have is that they are making brick and concrete to hard and brittle.If it get wet and freezes it will spall.With the damage I've seen to 20 year young foundations,I have my doubts they wall last as long as the 120 year old lime puddy mortar and rubble stone foundations that I very rarely get calls to repair.I'm not hating on concrete-I make a living from it-but it's very very far from a superior building material
As for maintenance free,look at any new home foundation or concrete floors or look at all the cracks in the floor at your local home depot.Properly fixing it is not a small or easy job.Plus it does not breath or dry out easily causing dampness and maybe mold and the concrete may even rot.
Harder and stronger is not always better.Movement and freeze/thaw can wreck concrete real quick.Softer(lower psi) concrete seams to hold up much better in the long term.From my understanding the ancient concrete that lasted so long is a much weaker,more flexible and breathable material.
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