Shop name for a mix built on 3/8 in rounded or crushed coarse aggregate, with more sand and paste than a standard 3/4 in or 1 in mix. The small stone travels through the 2 in to 3 in hose of a line pump without packing off, which makes it the default for residential foundations, backyard slabs and narrow forms. The extra paste raises cost and shrinkage, so engineers often limit it on large structural slabs.
Order it as a pea gravel mix, the line pump only runs a two-inch hose and that 57 stone will plug it.
Also heard as
- pea rock
- pump mix
- 3/8 mix
- pea gravel
Related terms
Aggregate
The sand, gravel and crushed stone that make up 60 to 75 percent of a concrete mix by volume.
Boom pump
A truck-mounted concrete pump with a folding hydraulic boom that places concrete right where it is needed.
Plug
A blockage that jams a concrete pump line or hose, stopping placement until it is cleared.
Mix design
The recipe for a concrete mix: the weights of cement, SCMs, water, aggregates and admixtures per cubic yard.