Fillcrete under slab-on-grade
Fillcrete under slab-on-grade
(OP)
I specified granular fill under a new slab-on-grade. As our winter is more or less upon us in Saskatchewan, the contractor has asked whether the fill could be replaced with 5 MPa fillcrete. Our typical slab-on-grade includes reinforced concrete over a poly-barrier over at least 150mm of well compacted granular fill. Any weak spots identified during proof rolling to be excavated and filled.
As I've never specified fillcrete before I have a few questions/concerns:
1) Is fillcrete permeable like granular fill, or should that be a concern? There's a sandy/silt layer under the would-be granular fill.
2) Does fillcrete change in volume, or shrink, during curing? If so, is it any more so than compacted granular fill? Perhaps the most compaction will occur under the fillcrete.
3) Where should the poly barrier go; over or under the slab? Or do I no longer need a poly barrier?
4) Are there any special specifications or notes that should be included on the drawing set?
4) Are there concerns over and above the ones I have listed?
Thank you in advance,
Paul
As I've never specified fillcrete before I have a few questions/concerns:
1) Is fillcrete permeable like granular fill, or should that be a concern? There's a sandy/silt layer under the would-be granular fill.
2) Does fillcrete change in volume, or shrink, during curing? If so, is it any more so than compacted granular fill? Perhaps the most compaction will occur under the fillcrete.
3) Where should the poly barrier go; over or under the slab? Or do I no longer need a poly barrier?
4) Are there any special specifications or notes that should be included on the drawing set?
4) Are there concerns over and above the ones I have listed?
Thank you in advance,
Paul






RE: Fillcrete under slab-on-grade
Without further information, I would have to say no.
Mike McCann
MMC Engineering
RE: Fillcrete under slab-on-grade
RE: Fillcrete under slab-on-grade
As Mike notes, one of the purposes of granular material is to act as a bit of a capillary break... this is recognised by the Ontario Building Code as well... I haven't had much confidence in this, in particular, if your fine material is in the range of 7 or 8% or more.
Dik