When normal ready-mix concrete is made the largest aggregates in the mix can range from 1-1/2 inches down to 3/8ths of an inch in size with compressive strengths that can be as high as 10,000 psi.

Ready-mixed concrete being poured from a mixer truck - Avalon_studio/Getty Images For almost a century, the way to deal with concrete mix that's been in the truck for 90 minutes or more was simple and ...