where to buy suitable bag mix for concrete benchtop in Melb Aus?

[crwdtb]

Gday
I was just searching for an appropriate concrete bag mix in melbourne Australia that would be sufficient to use for a concrete benchtop, ie a portland II or III type. Any help much appreciated.
Cheers

[brickie in oz]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

Save your money and time with bagged concrete as its only good for door stops when it goes off in the bag.
Apart from being 100 times more expensive than delivered premixed stuff its all rubbish.

[Vicbrickie]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

just mix your own. I did

[crwdtb]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

So should I just get it delivered?
but the problem is , that it is for a benchtop and I don't need that much, so do they dump the rest on the lawn?

[brickie in oz]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

How much do you need?
Can you use it anywhere else in the yard, I think the smallest they will deliver is about 0.2M3 which is about 3 wheel barrows.
You have to tell them what its going to be used for so they can mix in the prettier rocks.

There is no way I would use bagged muck unless you are setting fence posts.

(If ever I build my own house I will do a polished concrete slab with river pebbles in the mix.)

[david s]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

The cheapest way to go is to buy the sand, aggregate and cement separately and mix it yourself. you should be able to buy small quantities from landscape suppliers. If you go to a fish and chip shop they always have plenty of 20 L drums you can pick up cheaply, then use them to fill with materials and cart it around in a standard sedan.

[Vicbrickie]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

I agree with david s. the other advantage to mixing yourself is that you can have total controll of what goes into it so if you want to expose the agregate by grinding you can have any look you want.
I matched the same pebbles as my driveway and used off white cement with white washed concrete sand

[david s]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

The cheapest way to go is to buy the sand, aggregate and cement separately and mix it yourself. you should be able to buy small quantities from landscape suppliers. If you go to a fish and chip shop they always have plenty of 20 L drums you can pick up cheaply, then use them to fill with materials and cart it around in a standard sedan.

Until I bought a small truck recently, I bought and carted all my materials in a 1990 Suzuki swift. I would call into the yard, which was on the way home from work, so it never meant creating extra travel expense, and fill three 20L buckets. The buckets are not too heavy to lift, but you have to be careful not to stop or turn too quickly.

[crwdtb]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

thanks for your replies but the problem is I don't want to spend all that time building a mould and so forth then put a mix in it that isn't right as I have only mixed cement for slabs for the oven and so forth nothing that needed to be polished with a wet grinder.

[crwdtb]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

Hey guys took your advice and went and got some portland cement , sand, and used some small river stones as aggregate and some water reducer to give me a nice mix, I have done a test section before making the big mold and also did a control with premix cement. I can already see the difference, thanks so much for steering me in the right direction, the benchtop would have been a botch job with premix. great forum this.
Cheers

[Vicbrickie]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

good idea with the water reducer. helps keep you water/cement ratio low and the harder your concrete the eisier to get a high polish.
Have you thought reinforcement yet?

[crwdtb]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

Obviously reo around perimeter with mesh through out, I was going to give poly fibres a miss, I just think it might be a bit of overkill?
Can you use to much reducer? I had about 35ml for a test piece with 5kg portland cement , 16kg aggregate , 15kg sand, 1.2lts water.
obviously I will keep the ratios if it works out ok. it certainly looked good going in the mould. easy to work and no water rising even after hitting it with the vibrating sander on the mould.
Any ideas appreciated
Cheers

[Vicbrickie]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

sounds like a good mix to me. I dont use any fibres also think overkill unless your trying to go really thin. Not sure how much reducer would be too much but if that ratio works (im sure it will) stick with it. Wet cure it for at least few days. grind after 1/2 weeks, polish 2 weeks later or when its taking a polish well.
I dont call myself an expert but done it enough to know it works. good luck!

[crwdtb]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

thx brickie, by the way I have a wet grinder with grit pads that range from 50 right up to 3000, do I just hit it with that? or first with a grinding wheel?

[david s]

Re: where to buy suitable bag mix for concrete benchtop in Melb Aus?

crwdth,
you can use too much superplasticiser (water reducer) If you do you get separation, ie. the aggregate sinks to the bottom. It sounds like you used the correct amount if this did not happen. There should be instructions on the product telling you how much to add.
Dave