Random or out-of-joint cracking in slabs on ground may affect appearance and performance, and typically will increase future maintenance costs. As shown here, vaulting and differential movements occurred across the crack and edges have spalled due to hard-wheeled traffic, all caused by improper joint spacing. When troubleshooting slab cracking, consider: joint spacing, saw depth, saw timing, restraints, reinforcement and location of reinforcement, amount of reinforcement crossing the crack and concrete shrinkage. All of these influence the cracking potential of slabs on ground.
Learn more about concrete cracks from Kim Basham, PhD, PE, in TH16 Troubleshooting Concrete Cracks.