Friday, February 17, 2012

Rammed earth, one week on

So my little rammed earth test wall/block has been in place for a week, covered with plastic so it was out of the weather.  Time to see how it looks!

Although it’s lightened a little as it’s dried, I’m still not thrilled with the colouring.  The natural soil is a rich orange-brown which would make a beautiful wall but with the grey cement and grey sand, the colour is dulled considerably. When we come to ram the walls for real I’ll try and source some off-white cement and yellow brickie’s sand, which should result in a colour more closely matching the natural soil.

What’s interesting is that as the block has dried, the cracks have developed a little more. The one which was caused by a dry patch in the mix has grown slightly, but new cracks have opened up at the base. My suspicion is that this is due to the relatively high clay content of our soil, and that I mixed it two-to-one with sand which has caused it to shrink a little too much as it’s dried. I think I’ll need to ram another test block with a higher percentage of sand, and perhaps raise the cement to 8% or so. All good learning! :)

This one highlights the need for a good, even mix too… I really must invest in that cement mixer :)

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