What materials are used in mudjacking?

Mudjacking uses a slurry mixture of Portland cement, sand, and water and sometimes with added soil or fly ash and pumped beneath the slab under pressure. The mixture fills the void space and lifts the slab as additional slurry is injected. Unlike polyurethane foam the slurry is a natural mineral-based material that eventually sets to a firm but not rigid mass beneath the slab.