Joint Fillers and Sealants are used for a variety of commercial and residential applications. Exposed concrete floors have sawcuts in them to control cracking (called control joints).  They pose a couple of problems.  If left empty, they collect dirt. If there is high traffic with forklifts and pallet jacks, the point loads at the wheels can cause damage to the side of the joint wall. Therefore, you have the option to fill them. They can be filled with something flexible (urethane or silicone caulk) mostly for cleanliness or they can be filled with a semi-rigid material (epoxy or polyurea) to help support the joint wall from fracturing (spalling) due to the traffic.