Flowable fill is a self-leveling, cement-based fill that pours straight from the truck and finds its own level — into pipes, culverts, tanks, manholes, annular spaces, and under-slab voids that compaction equipment simply can't enter. No tamper, no plate, no lift-by-lift placement: it flows around obstructions, fills every cavity completely, and sets into a firm, settlement-resistant mass that supports whatever sits above it.
That self-compacting, controlled-density behaviour is exactly why flowable fill — also called controlled density fill (CDF) or unshrinkable fill — is the go-to for abandonments and void filling. The mix is engineered to a deliberately low strength, so it can still be cut or excavated later if access is ever needed, yet it permanently immobilizes an abandoned line or cavity so nothing migrates, collapses, or settles behind it.
Filling an open utility trench or restoring a road cut instead? That's a different job family — see our Controlled Low-Strength Material (CLSM) page for trench backfill and pavement reinstatement. Both come from the same OE U-Fill trucks.