Mars: Readily usable sulfur for sulfur concrete?

Question

Sulfur concrete is a mix of sulfur and aggregates that make a strong, quick-hardening concrete that is likely to be used for construction on Mars, which has a great deal of sulfur. Most experiments, however, seem to use commercial sulfur, which is relatively pure, while a great deal of sulfur on Mars is in the form of sulfate salts such as Ca-, Mg- and Fe-sulfates.

To get an initial structure built, are there any places on Mars:

1. With sulfur deposits having some pure or purifiable sulfur, or any form of sulfur that can be quickly and easily converted to at least moderately pure sulfur? (Aggregates in the mix is fine, they would just add less later.)

2. That are relatively easily accessible (no deep digging or apparent risk of life and limb).

3. Are near the Terra Meridiani or Arabia Terra area, where I'm hoping to place my proto-colony? It is one of the areas of Mars that is high in sulfur, although primarily in sulfate form, as seen in one of the images in this eurekalert article.

Answer 1

Don't be too hasty to disregard the sulfur salts as a construction material.

Gypsum is a calcium sulfate that has been used to create concrete-like paths, artificial pillars underground and for the construction of walls.

For paths, confining form work is placed on the ground and filled with gypsum which is then sprayed with water to set off the gypsum so it hardens into a concrete-like pathway.

To make artificial pillars, the gypsum needs to be conveyed pneumatically to a hose nozzle at which point water is added and the resulting wet gypsum is sprayed on to the base structure upon which the pillar will be formed. Gypsum cannot be conveyed wet as it starts to set immediately upon getting wet.

For walls, bags of gypsum are briefly submerged in water and then place side by side and eventually on top of previous wet bags to form a wall. Steel reinforcing, or similar, can be used to give the wall more strength. To seal the wall and to give it smoother finish, it could even be sprayed with wet gypsum as used in making artificial pillars.