Following an earlier posting here, which linked to a cement enthusiast, here’s something which I did not know about the sort of sand that is used to make concrete:
The problem lies in the type of sand we are using. Desert sand is largely useless to us. The overwhelming bulk of the sand we harvest goes to make concrete, and for that purpose, desert sand grains are the wrong shape. Eroded by wind rather than water, they are too smooth and rounded to lock together to form stable concrete.
The sand we need is the more angular stuff found in the beds, banks, and floodplains of rivers, as well as in lakes and on the seashore. The demand for that material is so intense that around the world, riverbeds and beaches are being stripped bare, and farmlands and forests torn up to get at the precious grains. And in a growing number of countries, criminal gangs have moved in to the trade, spawning an often lethal black market in sand.
What is needed is to pour desert sand into a Gizmo, and for the Gizmo then to grind up the desert sand into even smaller particles, and then to reassemble them, with 3D-printing, into the better sort of sand. Easy.
Until now, for me, sand shortages were the stuff of jokes about what would happen if communism came to the Sahara Desert. (For fifty years, nothing. Then …) Blog and learn. As I often like to say when I blog.
If this right-sort-of-sand shortage gets worse, it will presumably have architectural consequences.