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Interesting paper on making concrete on the moon: https://adsabs.harvard.edu/full/1985lbsa.conf..381L https://adsabs.harvard.edu/full/1985lbsa.conf..381L

• adrian_b 4y ago
  That paper is not careful about the meaning of the used words and it does not discuss any of the difficult parts. "Concrete" normally refers to rocks that are bound with cement, without having to use high temperature and/or pressure. The paper does not explain how such a cement could be made from lunar rocks. The Portland cement and most other usual cements, which are used on Earth, require water, which is not available in most places on the Moon. What could be done is to extract the calcium oxide (quicklime), or other similar oxides, e.g. magnesia or yttria, from the lunar rocks. Without water, these oxides cannot be used to make cement, i.e. a binder that becomes solid without applying high temperature or pressure, but due to chemical reactions at low temperature. Nevertheless, these oxides can be used as binders in making ceramics, by sintering at a high temperature and moderate pressure, like making bricks on Earth. Thus one can make ceramics or glass on the Moon, which should be the cheapest materials, but not cement or concrete. There is no chance of making a building by pouring concrete, like on Earth. It should be possible to make a building from bricks, which might have shapes holding them together, but which must also use some metal parts, e.g. bolts or rivets, to ensure that they stay in place, in the absence of cement that could be applied like on Earth. It might be possible to seal the spaces between ceramic bricks with some kind of easily fusible glass, to make them airtight.
  • tyingq 4y ago
    There is a brief section called "Water Production".
    • adrian_b 4y ago
      That section can be safely ignored, because the proposed solution is not feasible, being based on non-lunar resources. Bringing hydrogen from Earth in quantities large enough to allow wasting it in construction materials, instead of using it only for making precious food and drinking water, for making water and acids used in certain chemical processes, for certain plastic materials used in small quantities and for fuel, is a completely impractical idea (this being a polite way of not calling such a solution for making construction materials on Moon as completely stupid). Hydrogen, nitrogen, carbon and sulfur will be the most expensive materials on the Moon, so they will be reserved for things where they are irreplaceable, not for construction materials, which are needed in huge quantities in comparison to the materials needed for any other application, so they must be made from the most abundant materials that can be found around.