Saturday, October 13, 2007

RE: [papercreters] QUANTITIES of WATER and CEMENT in PC [papercrete]

I slowly add cement as the water fills the tank (200 gal tow mixer). The water pressure mixes the cement in well. Then I add the newspaper and wet it, still while the tank is filling with water and then the aggregate. The water ends up at about 4 inches below the top of the tank and does splash out when I first start rolling. The consistency of the final mix is like watery oatmeal. I agree with the previous comment that too little water really makes for more work emptying the tank and evening out the mix in the form.
What I did when I was first getting started was to just think it through and then do whatever seemed like it might work. It took a few tries (and I still have some inconsistency) but I'm happy with the quality of my blocks. Good luck with yours. Judith


To: papercreters@yahoogroups.com
From: sklarm-yahoo@screwdecaf.cx
Date: Sat, 13 Oct 2007 08:17:37 -0500
Subject: Re: [papercreters] QUANTITIES of WATER and CEMENT in PC [papercrete]

I find it helps to think of papercrete requiring a MASSIVE amount of water. In my case so much water is required due to my tow behind mixer needing to create a vortex to evenly break down the paper. When I short myself water I spend a lot more time mixing and end up with huge chunks. I eyeball the water level. All I look for is that PC solids and water low enough to not spill put of mixer while mixing.

On Oct 13, 2007, at 7:45 AM, "ElfNori" <elf@elfnori.com> wrote:

You'll get lots of posts on this.  The water/cement relationship in papercrete bears no relation to that in ferrocement or even regular cement.  We're talking completely different solar systems, not just different planets.
 
ElfN
 
----- Original Message -----
Sent: Saturday, October 13, 2007 4:49 AM
Subject: [papercreters] QUANTITIES of WATER and CEMENT in PC [papercrete]

In the discussions and recipes I am researching I do not see a lot of
information about the water that is used. Without any experience in
using PC, I know in my daily constructionwork with concrete that the
amount of water and the impurities in water are important factors for
the quality of the mix and I suppose that that also counts for PC.
Is there somebody in the PC community that can shed some light on this
topics?
How do you measure the amount of water in a mix
[eyeball / by volume / by weight / just guessing / ....]
When do you add water?
[start with water and add all the components / start with wetting the
paper and later add more water / have no particular following order / ...]
What water do you use?
[Drinking water / water from a pond / ....]

In the article Concrete Basics that you can find at
http://www.cement.org/basics/concretebasics_concretebasics.asp
I read=>

A properly designed concrete mixture will possess the desired
workability for the fresh concrete and the required durability and
strength for the hardened concrete. Typically, a mix is about 10 to 15
percent cement, 60 to 75 percent aggregate and 15 to 20 percent water.

The water-cement ratio is the weight of the mixing water divided by
the weight of the cement. High-quality concrete is produced by
lowering the water-cement ratio as much as possible without
sacrificing the workability of fresh concrete. Generally, using less
water produces a higher quality concrete provided the concrete is
properly placed, consolidated, and cured.

Excessive impurities in mixing water not only may affect setting time
and concrete strength, but also may cause efflorescence, staining,
corrosion of reinforcement, volume instability, and reduced
durability. Specifications usually set limits on chlorides, sulfates,
alkalis, and solids in mixing water unless tests can be performed to
determine the effect the impurity has on various properties.

Besides the water content it states=>
A continuous gradation of particle sizes is desirable for efficient
use of the paste.

=> Should we use other materials besides paper and sand with a bigger
particle size in a PC mix?
=> What would be usefull = light / strong / cheap / easy to get.

grtn
recipe researcher




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