Yes, this is the Lunarcrete, i.e. concrete made of water and regolith. But it would be made using steam, requires huge amounts of water which is a likely to be a precious commodity on the Moon at least for the near future (though eventually if we mine water from the poles, this might change). It would also require ultra high temperatures also to extract cements from the lunar regolith to bind it together.
Another idea is to use a Sulfur based "Waterless Concrete" ("Sulfur "concrete"). After all water is likely to be precious on the Moon. And sulfur concrete has many advantages for the Moon over water based concrete.
It's not strictly speaking a "concrete" in the ordinary sense as there is no need for curing and no chemical reaction involved. Rather the sulfur acts as a binder for the regolith.
This is a big advantage on the Moon. You can just mix the sulfur and the regolith together, and heat it up until the sulfur melts, which it does at the low temperature of 115.2 °C, indeed, the lunar surface at high lattitudes can reach 123 °C at the middle of the 14 Earth days long lunar "day".
Then you form the blocks, or spread it over the surface if you want to create a flat surface such as a launching pad - and it will "cure" immediately. This reduces the time needed to construct buildings and also reduces the time that astronauts need to spend on the surface.
You can mine the sulfur on the Moon as it has veins and deposits of troilite, (FeS) which is rich in sulfur.
The best mixture of regolith and sulfur for this concrete consists of 35% sulfur, 65% regolith (because the lunar rocks brought back from the Moon are so precious, experimenters use regolith simulants for the Earth based experiments).
It can be made stronger by addition of 2% aluminium fibres, and some silica.
Main disadvantages are
Other ideas for construction materials include just heating up the regolith until it melts and using that to form blocks, but these are likely to be extremely brittle.
For cosmic radiation shielding, it's also possible to just pile the regolith on top of a habitat to a depth of several meters. In this case the habitat woud be one constructed on Earth, for instance a Bigelow type inflatable habitat - and then when you get this to the Moon you cover it to a depth of several meters with regolith using earth moving equipment - basically just a small bulldozer on the Moon. Which could also be operated remotely from the Earth until the base is ready for humans.
Another possibility is to live in caves for the first settlements. Though since caves are rare and unusual and scientifically interesting on the Moon - I think that would depend, I think, on first doing scientific investigation of the caves in their pristine state.
E.g. the suggestion has been made that they may have ice deposits like the poles of the Moon. Which may also include traces of organics and other chemicals as well as tell us about how water is transported in the lunar "atmosphere" over geological time. So, before exploiting them, you would want to investigate for organics and trace gases, and generally take advantage of the present day opportunity to study the Moon in its original pristine state.
Also, though there are several caves already discovered, but not hugely many. If some day we have extensive settlement on the Moon, I think there may be a wish to preserve some of the original lunar caves, or parts of them, in their original condition for scientific study, and indeed for general appreciation also.
See also the io9 article: This Is Lunarcrete, a Building Block for Moon Colonies
And I've just added a section on Sulfur concrete to the wikipedia article on Lunarcrete: Lunarcrete- Sulfur based "Waterless Concrete"
Another idea is to use a Sulfur based "Waterless Concrete" ("Sulfur "concrete"). After all water is likely to be precious on the Moon. And sulfur concrete has many advantages for the Moon over water based concrete.
It's not strictly speaking a "concrete" in the ordinary sense as there is no need for curing and no chemical reaction involved. Rather the sulfur acts as a binder for the regolith.
This is a big advantage on the Moon. You can just mix the sulfur and the regolith together, and heat it up until the sulfur melts, which it does at the low temperature of 115.2 °C, indeed, the lunar surface at high lattitudes can reach 123 °C at the middle of the 14 Earth days long lunar "day".
Then you form the blocks, or spread it over the surface if you want to create a flat surface such as a launching pad - and it will "cure" immediately. This reduces the time needed to construct buildings and also reduces the time that astronauts need to spend on the surface.
You can mine the sulfur on the Moon as it has veins and deposits of troilite, (FeS) which is rich in sulfur.
The best mixture of regolith and sulfur for this concrete consists of 35% sulfur, 65% regolith (because the lunar rocks brought back from the Moon are so precious, experimenters use regolith simulants for the Earth based experiments).
It can be made stronger by addition of 2% aluminium fibres, and some silica.
Main disadvantages are
- It is not so good at shielding from cosmic radiation and solar flares. Concrete is excellent for this because of the presence of water. So walls need to be thicker
- The sulfur melts at midday temperatures in equatorial regions. It also goes through structural changes when temperature differences are large (there are many different allotropes of sulfur with different arrangements of the atoms - this is what causes the wide range of colours of sulfur deposits). So large changes of temperature could change the volume as it transitions from one to another of those allotropes.
So it would need to be used at higher lattitudes, or in shadowed locations, or protected from the midday extremes by another outer layer. The recommended maximum temperatures is less than 96 °C and with the "day / night" monthly variations in temperature not exceeding 114 °C.
Other ideas for construction materials include just heating up the regolith until it melts and using that to form blocks, but these are likely to be extremely brittle.
For cosmic radiation shielding, it's also possible to just pile the regolith on top of a habitat to a depth of several meters. In this case the habitat woud be one constructed on Earth, for instance a Bigelow type inflatable habitat - and then when you get this to the Moon you cover it to a depth of several meters with regolith using earth moving equipment - basically just a small bulldozer on the Moon. Which could also be operated remotely from the Earth until the base is ready for humans.
Another possibility is to live in caves for the first settlements. Though since caves are rare and unusual and scientifically interesting on the Moon - I think that would depend, I think, on first doing scientific investigation of the caves in their pristine state.
E.g. the suggestion has been made that they may have ice deposits like the poles of the Moon. Which may also include traces of organics and other chemicals as well as tell us about how water is transported in the lunar "atmosphere" over geological time. So, before exploiting them, you would want to investigate for organics and trace gases, and generally take advantage of the present day opportunity to study the Moon in its original pristine state.
Also, though there are several caves already discovered, but not hugely many. If some day we have extensive settlement on the Moon, I think there may be a wish to preserve some of the original lunar caves, or parts of them, in their original condition for scientific study, and indeed for general appreciation also.
See also the io9 article: This Is Lunarcrete, a Building Block for Moon Colonies
And I've just added a section on Sulfur concrete to the wikipedia article on Lunarcrete: Lunarcrete- Sulfur based "Waterless Concrete"
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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