Many of these properties do not have a significant real property element, outside of land, as the plant is often not permanently affixed. Doesn't sound like that is the case for your property, but it might be for potential sales.
On occasion, I'll see batch plants or redi-mix checked as sales when going through green sheets at the courthouse, but I rarely bother writing them down. I should get better about that.
Costar doesn't have a secondary property type for this, but if you do a keyword search for redi mix (maybe try spelling that a couple different ways), there are some hits. Just make sure to zoom out and go back in time. Talking to people working in the industry about sales could yield useful leads, as well.