Canadian carpenter Dustin Bowers, founder of a company called PLAEX, has figured out how to turn waste into a useful building product. Bowers started by shredding the least desirable materials of all: Difficult-to-recycle agricultural, marine and industrial plastics, and aggregate waste from the construction industry. He then mixed this waste in with concrete, and molded it into the blocks you see here:

These blocks, called PLAEX-crete, can be stacked like Lego:

By content, PLAEX-crete blocks are more than 90% waste. And they're useful: They're 33% lighter than cinder blocks, and can be used to build walls in a fraction of the time. In one test, Bowers had two teams compete to build the simple walls you see below. On the right are traditional cinderblocks and mortar. On the left, PLAEX-crete.

The PLAEX-crete blocks self-align and do not require mortar. In the time the cinderblock team assembled their wall, the PLAEX-crete team had built their wall, torn it back down, and built it again. (You can watch the test yourself here.)

The speed of assembly should be a boon to contractors, who can spend the saved time on other tasks. The ease of assembly should appeal to DIY'ers, who will not need mortaring skills to complete the task. It's also convenient that the PLAEX-crete blocks can be disassembled, moved, and re-used.

Another benefit is that the PLAEX-crete mixture is more watertight, durable and impact-resistant than cinderblocks. Watch what happens when a front-end loader crashes into each:

(Admittedly, the mortar probably hadn't had long to cure.)

Additionally, the material takes fasteners well.

Bowers says the cost of a PLAEX-crete block is "comparable" to that of a cinderblock. The real cost savings comes with the saved labor time.

At present, PLAEX-crete blocks can only be used to build retaining walls, sheds and other non-occupancy structures. The company is currently putting the blocks through standards testing, aiming for CSA and ICC certification, so that they can be used in homebuilding. The location of the dovetails on the long sides of each block were placed with this in mind: Once assembled, 2x4s fit within the dovetails perfectly at 16" on-center.

Bowers also envisions that, used for interior walls, the blocks open up the intriguing possibility of rearrangement over time:

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Here's a look at how they're made:

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