In Northern Ireland, Castles were constructed with stones mortared together from beach sand, slaked lime and blood. They are still standing after 700+ years in very harsh salt water environment. Egg Tempre has been used as a visual art's medium for several hundred years by many fine artist. Many binding agents can bee found in nature to produce near permanent structures. Termite mounds can withstand both extreme heat and wind with nothing more then secretions.

That does not sound normal; making stools out of urine.

Blood! I guess that must have been "donated" by workers who collapsed, or the old and infirm. :o) Easier, and friendlier, to give them lots of beer to drink, and harvest the processed excretions. Also, slaked lime is hardly benign, so this is probably an improvement. Calcium carbonate is just chalk, though, so I wonder what binds this stuff, too; he handled the finished block very gently. The microbial action must bind it somehow.
And the termites, yes, as well as various birds, bees, and amphibians. I love that the bio-mimicry movement has gotten so large. Very exciting.

I first saw this idea in a ted talk by Magnus Larsson, he wanted to adapt this process to build a 'great wall' across Africa to halt Sahara desert spread. while not a new idea, i like the bricks, and would like to see some tested to destruction under a compression strength testing system. i especially like the shape, i can see it being used for bricking building walls, both in vertical and horizontal alignment.

Sounds like the "good old days" of collecting urine door-to-door fo the tanning industry! I suppose it is a bit better than the needy visiting blood banks and selling a pint or two for money. Have a few beers and sell your pint or three and help build something!

Harriet it states calcium chloride not calcium carbonate in the article.

Cutting edge is fine and dandy at the tip, but here is something for those who delve into first principals deep in the root. I like this because it addresses the root of things and concrete is a root thing.

I wonder what the chances are of this replacing current cement production technology. As things are, cement production is a major producer of the greenhouse gas, CO2.
Unfortunately, it would take a lot of fossil fuel energy, with consequent CO2 production, to convert to any radically new technology, such as this, so it is not all good news.

Three years ago I published a book called A SEVEN THOUSAND YEAR HISTORY OF CONCRETE*. One section of the book dealt with the use of concrete on the Moon. Obviously there is plenty of sand on the Moon and now they have a perfectly good use for the urine of the 'lunatics' who settle there.
*Quantuck Lane/ WWNorton Press

When EAWAG, the leading Swiss water research institute near Zurich got a new building they installed toilets which separate urine from solids. The technology exists and is feasible at least for larger buildings which have enough flow to create a waste stream.