Sulfur ‘concrete’ for lunar applications–Sublimation concerns

1 cm of sulfur concrete can deteriorate within five years in a vacuum.

“Studies have shown that 1 cm of sulfur concrete can deteriorate within five years in a vacuum [252].”

Challenges arise due to the low melting point of sulfur, which can cause sulfur concrete structures to melt during Lunar days, limiting its applicability in Lunar conditions.

“However, challenges arise due to the low melting point of sulfur, which can cause sulfur concrete structures to melt during Lunar days, limiting its applicability in Lunar conditions [250,252-254].”

The volatility of sulfur in low-pressure environments and outgassing add complexities to its application on the Moon.

“The volatility of sulfur in lowpressure environments and outgassing further add complexities to its application on the Moon [252,254].”

Loss of weight due to sulfur sublimation resulted in formation of cracks and pores in concrete.

“Loss of weight due to the sulfur sublimation resulted in the formation of cracks and pores in concrete.”

Sulfur concrete does not have proper performance in vacuum and high-temperature conditions.

“Research on the durability of sulfur concrete has shown that it does not have proper performance in vacuum and high-temperature conditions [252].”

Putting sulfur concrete in a vacuum for 58 days showed sulfur sublimation.

“Putting sulfur concrete in a vacuum for 58 days showed sulfur sublimation, as shown in Fig. 18.”

Sulfur sublimation drastically increases with temperature.

“It was also observed that sulfur sublimation drastically increases with temperature.”

It takes 3.5 years and 2 h to sublime a 1 cm layer of sulfur at 15°C and 120°C, respectively.

“According to results, it takes 3.5 years and 2 h to sublime a 1 cm layer at 15 ◦ C and 120 ◦ C, respectively.”

As temperature goes higher than 120°C near equators on the Moon, melted sulfur may lead to structural failure.

“As the temperature goes higher than 120 ◦ C near equators on the Moon, melted sulfur may lead to structural failure [252].”

NASA first suggested that lunar cement could be made from sulfur mixed with lunar soil.

“NASA first suggested that lunar cement could be made from Sulphur mixed with lunar soil. 151,152”

Cement contour crafting uses adhesives such as sulfur, alkaline solution, and organic solvents mixing the lunar soil to extrude lunar concrete, which has the advantage of low energy consumption and high compressive strength.

“Cement contour crafting uses adhesives such as sulfur, alkaline solution and organic solvents mixing the lunar soil to extrude lunar concrete, which has the advantage of low energy consumption and high compressive strength. 151-154”