The rammed earth piece is a result of milling a computer-generated 3-D surface and using it as a side to the formwork, which is traditionally simply flat planes. The result is a 3’x3’x8” piece of rammed earth.
My thesis involves rammed earth as a connection between the food process and our relationship to the earth. As a regional response to my site being in Silicon Valley, adding an element of digital technology touches on the present societal conditions and indeed provides an interesting interplay of raw material (earth) to our modern world through not direct interaction with digitized design, but rather traces experienced within the earth itself.
First, I developed a form that is clearly only possible through digital work. I made this an a-symmetrical composition in elevation to reveal the process through containing four possible orientations of the block. I decided on a 3’x3’ section as a manageable size to create a full-size prototype with the earth. The design is a ripple shape and slightly undulating in the other axis to add variety. I was as sensitive as I could be at this point to understanding the limits of tolerance and mount of detail possible with these ‘crevices’ in the pattern, knowing the ramming may be difficult in small spaces.
I’ve only just begun using Rhino, and received assistance from a classmate in realizing my form with the program. It was necessary to consider the form I was creating as actual negative space in the final piece of rammed earth. Since there would be a large amount of force exerted vertically against the piece, and clamps holding it to the others, I also had to include a wide enough backing so it wouldn’t break under the pressure (I believe this ended up being a little over a half inch).
I laminated twenty-five 36”-long 2x4s as my initial block material. This was clumsy and difficult as I’d never done it before and did little research in the proper method. I may have required planning the bottom surface regardless of how well I made this, but I definitely needed to do so with the quality of the board.
My project was programmed and a few days later the piece came out successfully, it looked beautiful. The cusp height was even less than I was expecting. It wasn’t a large factor be begin with, as I knew I could sand it down as much as I’d like and the earth had a considerable tolerance, so I sanded the piece as much as I could, based on the softness of the wood itself, and then treated it with polyurethane in an effort to try to salvage the piece after ramming if possible. After a little more sanding it was ready for assemblage. The other components of the formwork were a 2×4 screwed into either side of the piece, to temporarily connect it to the other piece of formwork through clamping, and 11” plywood sandwiched between the 2x4s and milled piece to provide the appropriate width. Two clamps were added to each side, which was probably enough, but I should have placed them closer to the top and bottom, as the formwork did open a little against the force of the earth and compacting.
I had spent several hours obtaining soil in the past few weeks, a difficult task with the (until recently) lack of vehicular access to the 6000 level courtyard, but thankfully I had enough and also had sand to offset the heavy clay content of Cincinnati soil. I made a mixture of about 6:3:1 of soil, sand, and Quickrete (to ensure stability). I was hesitant to use the Quickrete, but knowing this was probably my only built prototype with the form, it helped ensure success. After mixing the soil and adding a small amount of water to activate the clay, I added a little over a bucketful, probably six inches, which compressed down to around four. It took about three hours of this labor and then I removed the framework. Thankfully I had tamped enough to make almost all surfaces and edges smooth and without interruption.
A setback to using raw earth is what also makes it beautiful, its close relationship to other natural elements. This means that when it rains, it may be in more danger of degradation than a material developed by man and technology. For example, in the storm today I was worried that my piece would slump into a pile of mud and, while it certainly did not, this isn’t a fear one should have of architecture. Adding concrete helps, as well as capping the earth with a finish material or concrete, but then the question starts becoming, why not use concrete to begin with? One can make a thinner wall that will last and is very strong.
My objective with utilizing the earth is to surface in the audience a true emotion evoked not from memory, perception, or expectations, but rather what is right in front of them – earth straight from the ground and intelligently transformed with minimal chemical and industrial processing.