mix help

[rongo]

I need help as to what super plasticizer to use on landscaping curb, the mix is 4each 5 gal bucket sand to 47lbs Portland with fiber added should give me around 3200 psi. This mix is close to zero slump I live in Indiana and freeze and thaw on the finished curb will apply and I need a smooth finish so time to work with mix is very important. If any one could recommend what admixes to use. Thanks for any help

 

[dik]

More importantly, you need air entrainment admix AEA. Your low slump is OK, but you might consider sawcutting the curbs approx 6 to 8 hours after they are case... Superplasticisers are specific to the product and you would have to talk to the supplier.

Dik

 

[rongo]

Thanks dik for the info. The curb will be formed buy a landscape curbing machine and control joints cut every 2’ after we lay the curb trowel and stencil.

The mix:
4 each 5gal buckets mortar sand and 47lbs Portland. This will be mixed at job site.
Fiber added.

I need to add strength and curing time for finish toweling to achieve a smooth finished curb, I have read that some are using a spray after the curb is down to achieve a smooth finish? What would they be using to do this with? Any help!

I would like to prefect this mix to ease the working of the curb and finish (troweling and stamping)

 

[dik]

By fibre, I assume you are using polypropylene... I'm not sure this will be effective. You don't seem to mention any coarse aggregate; I would think that you would have some 3/4" stone. The sand only would make it more difficult to have any freeze thaw resistance without compromising the strength. You need a good mix, probably about 35 MPa, and about 7% air. Slump should be limited to about 3" maximum.

Mix design is closely tied into the local aggregate; it has an effect on the moisture conditions of the material that you are using. You'd be best served by talking to a local concrete contractor or concrete supplier. I can produce a concrete design and even locally, it would have to be 'tuned' to suit.

Dik