This is Rock 'N' Roller, it's a concrete roller created by Marshalltown. Concrete is usually stamped with mats, which requires moving each mat into place and pushing them into place.
The Rock 'N' Roller allows you to stamp concrete 5 times faster than mats according to Marshalltown. Once the concrete is flattened you simply spray the concrete and roller with a liquid release agent, then roll it over the surface.
They can be up to 90cm wide, and come in a variety of sizes for different jobs.
Read more: http://www.businessinsider.com/sai