Malleable urea for lunar concrete

Layer-by-layer build of mixture containing 3% urea.

The mix coming out of a 3D printer proved to be stronger and retained a good workability – a fresh sample could be easily moulded.

After water, urea is the most abundant component of human urine. Urea can break hydrogen bonds and reduce the viscosities of fluid mixtures. Urine also contains calcium minerals that help the curing process.