I have been looking at the flyash, I will admit it makes me nervous to work with. It has so many carcinogenic substances in it. I am not sure I will proceed.
My roof mixture is simple, 50/50 dry paper and cement by weight. The bottom layer, that is between the rafters is held in place by a sheet, when dry. We use boards to hold it until it dries. Then a layer of heavy fencing that is tied down with plumbing strap, and another 5 inches of paper crete on top of that, that goes over the rafters. The top coat is petrified hessian.
Our walls are the same mix of paper and cement, but we add sand. My mixer nicely handles 30 lbs of paper, so it gets about 30 pound of cement and ten pounds of sand in the walls. I found that here where life is very humid, any clay will start growing. I do not want weeds growing on my walls.
We had tried a reciprocal roof, that failed. And I didn't like it, the pitch was way too high, so when it failed, we were not all that upset. Except we wasted a years work on it. And I had to redo the drawings etc. We have made a few more changes, the house is growing organically. But, the final product is getting closer and closer to what I really want.
Hello Kim
Hope things are going well on your project. I finally finished my Papercrete just before Thanksgiving. All and all it was about 2,000 cubic feet to pour. I used a slip form. We poured new Papercrete walls against our existing Mobil home. W' e have free standing Papercrete at the addition. I have enclosed a picture of the form system and the finished pour. I still have to do the skim coat and waterproofing coat.
To the Flyash issue, I have not heard of flyash as a stand alone binder. Typically in concrete it is used as a supplement to cement to reduce the amount of cement required.
Before i began construction on our house i built a barn as my testing lab. for my initial work I tried to maximize paper and minimize binder. I did a mix with lime and wood ash that was very promising. The logistics of trying to get that much ash mad it seem like more than I could manage.
The mix i test was ( by weight)
paper 28%
clay 40%
Wood ash 19%
lime 13%
This was a stronger product than what i was getting with what I thought was comparable with cement. When I finally got a mix that I thought was what i need i got some compression tests. Compression strength was way too low.
Based on my final cement mix I think you can test a mix with these proportions ( by weight)
Paper newsprint) 14%
Clay 15%
Sand 27%
Ash 27%
Lime 17%
Please let me know what you come up with.
Best
Murry Holley
