Mandeep Singh, a graduate student from India, conducted research on lunar earthbag structures for his master’s thesis at Auburn University, Alabama. This is a very interesting and exciting find that has obvious applications here on earth, particularly for the construction of lightweight, insulated vaults. Custom shaped, top connected bags were filled with vermiculite with a screw auger. It may be possible to fill bags with sand or loose, dry soil and eliminate tamping with this method. Another big thanks to Patti Stouter for finding this paper.
Construction Technique and Strength of Connected Regolith Bag Structures
I have seen that tubes connected along one side can provide lengthwise stiffening. I believe that this could lead to something, particularly with more stable but light fills.
My mesh tubes filled with trash operate like this when sewn along both sides. I’ll have to try making enough filled with foam trash to make a small vault. It would definitely need some rebar or wire mesh, but if this could make it firm enough to receive even a micro-cement layer that would provide a structural skin, it might reduce the weight of roofs and the amount of material needed.
If these bags were stretched over a form, they might be able to be tamped into place. Vermiculite would not be a viable material for this, however, it would crush to powder. Interesting concept for vaulted ceilings.
Regular earthbags would slide out sideways. Vaults are very tricky.
This system is only applicable for specially sewn together units of a specific dimension…in other words, it is a pre-manufactured system that lacks the versatility of earthbags as we know them.
It really does rely on the tension of the fabric that covers the top, so if this fails at some point, the structure becomes vulnerable to collapse. You could see in several of the photos how flimsy it really is, with portions wanting to deform…and this is without any load whatsoever being applied to the exterior in any direction. In the real world how long would this last? I can tell you that I would be reluctant to stand on such a structure. It works, partly because the vermiculite is so light, but it also compresses enormously. I think that the concept would be best used as an inflatable toy for use at a party or fair…not as a habitable structure. Or possible it would work on the moon because of the lack of gravity there.
Yeah, but plaster skins with mesh would likely add sufficient strength for small structures. I think this has some potential, although the bugs would have to be worked out. They had a difficult time filling the bags.
This building system lends itself to specially made units made in a factory. This system could overcome the problems of trying to build vaults with typical earthbags, which are not practical beyond about 6′-8′ wide. For sure, this is an exciting new development. I would love to have a lightweight, insulated structure filled with scoria.