By locking together prefabricated concrete bricks like pieces of lego, the ‘zipper truck’ can quickly construct tunnels, building a quarter mile long tunnel is less than 24 hours. Developed by Lock-block Ltd, a construction material production company, these durable tunnels are estimated to save up to 90% of construction costs. This is possible due to specially designed concrete blocks and trucks.

Like lego pieces, the blocks are secured by interlocking pegs and require no adhesive. The arched rollers on the back of the truck function as the frame for the tunnel structure, supporting the blocks while they are set in place. There is no need to wait the usual curing process of 28 days.

The truck itself is tapered, with the from arch of rollers being taller than the rear. As the truck move, the blocks fall into position and compress, like a zipper.

The arches are seismically resistant and easily reusable when disassembled. You can watch this innovation ‘zipping’ together tunnels here.