* according to Yahaya Ahmed of Nigeria’s Development Association for Renewable Energies
Assuming they're using generic sand and not coarse-washed sand that is causing sand scarcity problems, I think concerns about digging may be overblown, but I can't imagine how a house built with circular plastic bricks joined with mud will hold up during an earthquake. That they're planning to build a 3-story house this way is kind of terrifying. I hope none of the load bearing walls are built like this.
For a better tested alternative, Earthships use vulcanized rubber tires filled with rammed earth for load-bearing walls, and reuse glass bottles as design elements in non-load-bearing walls.
Though it is possible to design bricks that mitigate these problems. Precious plastic has a system for building square hollow bricks that allow other materials to bear loads.
I'm curious how they plan to keep the bottles from breaking down in the sunlight. Plastic becomes brittle when exposed to sun for too long, and I'm not sure the exposed bottle ends are protected well enough.
Seems like they're covered with the mortar "While the “bottle brick” technology might have caught on in Nigeria, it was initially tried in India, South America, and Central America close to a decade ago. It is a cost-effective and eco-friendly option compared with traditional brick homes, which makes it accessible to many."