cross-posted from: https://hexbear.net/post/8799405

Over a billion people in the developing world will move to cities in the next two decades, and dredging companies are ripping up river beds and seafloors to find concrete-quality sand.

China moved its construction industry to artificial aggregates, and will source future volumes from construction and demolition waste.

Chinese researchers also hope to turn their giant piles of coal gangue into usable building material, and thereby solve two major environmental problems at once.