Concrete placement to ramp slab - top-down, or bottom-up?
Concrete placement to ramp slab - top-down, or bottom-up?
(OP)
A lively discussion on a job site recently.
Construction of a carpark ramp between a ground floor (recently constructed slab on grade) and an upper parking level (recently constructed with PT).
Ramp is RC slab and beam at a slope of 16% (approx 9 deg). Length of ramp is about 20m (66').
There is NOT fully continuous reinforcement in the top of slab - only mesh/fabric over the intermediate RC support beams.
Line pump concrete mix is 80mm (3") slump and 32MPa (4500 psi).
Question: Do you start placement of concrete from bottom of ramp or top of ramp?
Assuming that cost of a line pump vs boom pump hire is approx the same.
Interested in your opinion.
Construction of a carpark ramp between a ground floor (recently constructed slab on grade) and an upper parking level (recently constructed with PT).
Ramp is RC slab and beam at a slope of 16% (approx 9 deg). Length of ramp is about 20m (66').
There is NOT fully continuous reinforcement in the top of slab - only mesh/fabric over the intermediate RC support beams.
Line pump concrete mix is 80mm (3") slump and 32MPa (4500 psi).
Question: Do you start placement of concrete from bottom of ramp or top of ramp?
Assuming that cost of a line pump vs boom pump hire is approx the same.
Interested in your opinion.






RE: Concrete placement to ramp slab - top-down, or bottom-up?
RE: Concrete placement to ramp slab - top-down, or bottom-up?
RE: Concrete placement to ramp slab - top-down, or bottom-up?
RE: Concrete placement to ramp slab - top-down, or bottom-up?
The replies from the jobsite from the engineers were bottom-up, to facilitate consolidation and be more self supporting, as others have commented above.
The jobiste contractor replies were top-down, to make it easier to "distribute" the plastic concrete down the ramp.
The contractor-types 'won' and they placed the ramp concrete from top-down.
But the engineers sort of won too, as in "we told you so" - the concrete slumped and resulted in 'plastic tearing' with full-depth slab cracking. Leaks like a sieve now.
RE: Concrete placement to ramp slab - top-down, or bottom-up?