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Trial Mix for CLSM
3

Trial Mix for CLSM

Trial Mix for CLSM

(OP)
I'm looking for a trial mix design for CLSM; hand batched at a mine site.

Gradation of Fine Aggregate to ASTM C-33 (this can be supplied)

50 lbs Portland Cement
150 lbs Fly Ash
2700 lbs Fine Aggregate as above
290 lbs water

no WRDA, AEA, plasticisers.

Does anyone have a workable trial batch mix that can be compared to this?

Dik

RE: Trial Mix for CLSM

Sorry Dik - don't have.  Took me a while to figure out you didn't mean the British Rock Group!  

Thats about 1.5% cement.  

We just had, for an unsurfaced wearing course, a 19 mm minus mix - with 25% between 4.5 mm and 19 mm; 55% between #200 sieve and 4.5 mm and 20% fines (passing #200 sieve). Used 2% cement. Standard Proctor was 2.3g/cc at 8% optimum moisture content. Compressive strength was 6.2 MPa at 3 days.

RE: Trial Mix for CLSM

that is about 2 sack mix (6% cement) when you count the flyash as cementitious material. Strength gain will be slow but could go over 500 - 600 psi. A bit too high for typical CLSM which would normally omit the flyash and stay with less than 1 sack mix, the material will not be easily excavated in the future.

RE: Trial Mix for CLSM

dik...that's right on track with several of the DOT mixes used in the US.  Yield is somewhere around 100 to 125 psi, so still excavatable.

If you have a copy, there's a table in ACI 229 that gives a variety of mix proportions.  Let me know if you don't have it.

Ron

RE: Trial Mix for CLSM

(OP)
Thanks, I'll dig up a copy of ACI229... I ran the mix through my mix design calculator and ended up with about 1.5 MPa concrete, about 200 psi...

Dik

RE: Trial Mix for CLSM

(OP)
I've published the above as a trial batch... what can go wrong? <G>

Thanks, gentlemen...

Dik

RE: Trial Mix for CLSM

If you throw a bunch of air in there, you can get the strength down some more and significantly reduce subsidence and bleed.  Most CLSM we do is >15% total air content for the low strength and very little bleed or subsidence.

Greg

RE: Trial Mix for CLSM

(OP)
Thanks conceng... it's not too late add some air.  It's not for a real critical loading issue... it's backfill for a large sump and the client has previously been using 'crushed rocksalt' and I was concerned about water entering the fill and 'softening' it.

Dik

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