Spalling of concrete slab on grade due to expansion
Spalling of concrete slab on grade or ground slab is usually caused due to insufficient expansion joint or restraint of slab against free temperature movements. These ground slab spalling cracking can be avoided by providing sufficient expansion gap between successive slabs. Usually these cracks are observed along the edges along adjacent slab which restraints movement causing weaker slab to spall of. Crack further propagates over time. Proper spacers are to be provided to allow thermal movements.