I think it is important with papercrete to not get too hung up on the CO2 levels of the building materials. If we are talking about dwellings (not fences) the amount of energy required to cool and heat the structure quickly heads towards zero if the walls are thick enough. This is a enormous amount of CO2 reduction compared to a standard home. The amount of CO2 saved each year will dwarf the amount of CO2 required to build the structure.

If you would like to skip the Portland cement that is possible. I have been removing it from my mixes. You can use a paper, clay, and lime mix also known as padobe. I have been experimenting with this for infill to a rebar structure. Keep in mind that lime is also a CO2 hog requiring even more energy to be cooked down.

In the end it just comes down to ‘what is your local resource?’ hauling clay from 60 miles away will do more damage than buying Portland cement from your local hardware store within 5 miles.

“Roughly 5 to 10 percent of global CO2 emissions are related to the manufacture and transportation of cement, a major ingredient of concrete.”

From: Industry scrambles to find a ‘greener’ concrete”

http://www.csmonitor.com/2008/0312/p14s01-stgn.html

Thoughts?

Replace “part cement” with “Portland cement”

We are experimenting with new recipes made from lime, clay, and paper. No cement or sand.

The new recipe is:
- 80lbs of paper
- 40lbs of paper cement

Paper cement? Did you mean 40lbs of cement?

We do not prep the paper at all before it goes in the mixer. In this video we are tearing the paper, but we don’t even do that now. If there is enough water the mixer can easily shred the paper without assistance or extra preperation. The magazine spines and phone books can all be used as is. We have found two cases where we prefer not to use any books with spines.

1. When shooting papercrete (we use a big air compressor and a hopper). The spines clog up the hopper.

2. When pumping papercrete. (we use a 3″ trash pump). The spines might be able to clog the pump, so we only use newspaper when pumping.

Although many types of paper can be used. I highly recommend securing waste newspaper sources. Newspaper is a weak fiber that breaks down easily with minimal amount of energy. Phonebooks, magazines, and cardboard can work, but they will add time and energy to your project. You will get the strongest most cohesive mix from straight newspaper.

Some relevant links:

Youtube video of papercrete being pumped:
http://www.youtube.com/watch?v=ZhoScNNYNQI

Youtube video of papercrete being sprayed on a shipping container:
http://www.youtube.com/watch?v=6DJZrrh8AVc

Youtube video of papercrete being sprayed on papercrete fence:
http://www.youtube.com/watch?v=9zOoKBgZ_8E

The tool we use to spray papercrete is a device called the “tirolessa sprayer” it is available for $225 from http://ferrocement.net . We also use a large air compressor (6HP, 60 gal, 11CFM, 220V) and 100′ of half inch hose. The combined cost of our spraying setup was just under $1000 for all items mentioned above.

We have sprayed papercrete to 1/2″ thickness. If multiple layers of expanded metal lath were used we could go to many feet of thickness. The lath can get expensive fast.

We have experienced the same as yourself as far as applying papercrete to a concrete surface. Our solution was to use old latex paint. This is the same paint we used paint the interior of our home 5 months before. We just added a cup or two of old latex paint to each 5 gallon batch of papercrete and mixed it in place with a handrill and egg beater end.

I’ve just finished sealing our 300′ fence of papercrete by using a elastomeric roof sealer paint. It was a expensive endeavor at $90 for each 5 gallon bucket. However, I believe our fence and stucco will survive for decades due to this investment.

We are going to try mixing a cactus called “Prickly Pear” tomorrow and see if we can use that as sealant. Several southwest based green builders and natives that have inhabited the land for centuries have used this cactus to block out moisure and as a cement alternative.

We considered smaller electric motors, but burnout and torq were the primary concerns. Today all we shredded was damaged phone books. Many motors would have gagged trying to deal with shredding 80 phone books.

If they are considering something as minor as the benefits of sequestration of carbon in the paper, they really must address the major waste of gasoline by hauling the whole truck and mixer about the yard. They could hook the mixer directly to a small gas engine, to the hub of the truck axle, or to a power takeoff.

YEAH, for taking the time and effort to make it yourself, instead of depending totally on the out-of-control corporateering building construction industry.

1. I produced a short music video which gives another view of the mixer which maybe helpful. The mixer is simply a old truck axle with that has been tilted 90 degrees and had a lawn more blade bolted to it. There are many websites about papercrete describing how to build your own “tow behind third world mixer”

http://youtube.com/watch?v=CGhD1ESUxPo

2. We have changed the recipe since the shooting over the video to lower our costs.

The new recipe is:
- 80lbs of paper
- 40lbs of paper cement

We do not pre-tear paper anymore. The mixer is good at that. We just use quite a bit of water. A dry mix does not vortex well enough to chop everything. Our mixes now take about 20 minutes to complete.

Just a thought,
Milt