While astronauts aren't back on the moon yet, they're already getting ready for construction.
The experiment is part of the Material Science on the Solidification of Concrete (Concrete Hardening) investigation, which is using different combinations of cement, water, sand, simulated lunar soil and "other additives", an experiment description states.
The goal is not only to build sustainable structures on the moon, but to find viable alternatives to cement — upon which concrete is based on Earth. Cement requires a lot of energy and raw material and can also release carbon dioxide in the manufacturing process, the experiment makers added. Complications can also arise during mixing, such as air pores, bubbles and brittleness. The experiment aims to smooth out these issues by testing out lunar construction on the ISS.
https://www.space.com/iss-astronaut-moon-base-construction-microgravity