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Old 10-10-16, 11:09 PM   #2
philb
Apprentice EcoRenovator
 
Join Date: Nov 2010
Location: Oklahoma City
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Hi Nibs,
EPSCrete is good stuff. I am currently building a shipping container house and insulating on the outside with basically the same recipe you are using. I do add flyash, fiber and "poly" to the mix. Poly is EVA (ethylene vinyl acetate). It's the plastic layer on smartphones and solar panels, just to name a few.

Fly ash makes a harder tougher end product. It also improves non-flammability.
Poly gets the eps beads to adhere better to themselves and "glues" to wood or steel substrates. Latex, Tite Bond Two and Elmer's wood glue are in the ballpark to what poly will do. I mix all additives with the portland in powdered form up to several weeks in advance. On pour day, I add sand, water, eps beads and the 5 gallon bucket of Portland powder mix. It's much easier and more accurate that way.

One ounce of polypropylene fiber goes into 6 cubic feet of product on all my mixes eps or concrete. It keeps it from cracking and improves the shock loads.

The house eps walls are one foot thick. The roof's slope is 1/2" per foot so it varies in thickness from 2 feet to one foot. Why so thick? I get a 24 foot Uhaul crammed full of clean eps every month. Also, in tornado and hurricane prone areas, epsCrete will absorb energy from flying objects.

A half inch layer of stucco covers the epscrete walls and half inch of ferrocement covers the roof.

I estimated the R value very conservatively at 2 also. There is a linear relationship between the amount of portland/sand and eps. You can graph it and get close.

I have a few bad videos on YouTube that illustrates it's non-flammability. The worst golf ball sized sample would burn with a propane torch flame directly on the sample and self extinguish once the torch was removed. The best would simply glow red. Oxygen and acetylene would probably reduce it to cinders.

Epscrete will absorb water and retain it throughout a hot summer so water reducers are important if it is poured in thick layers like one foot thick walls.

I still need to do more psi, break, crush and mutilate tests.

If there's an interest in epscrete, I'll dig up photos from G+. Ferrocement.net also has several large posts on this topic.
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