Trial Mix for CLSM 3

[dik]

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

 

[BigH]

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.

 

[cvg]

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.

 

[Ron]

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

 

[dik]

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

 

[dik]

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

Thanks, gentlemen...

Dik

 

[conceng]

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

 

[dik]

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