swimmingpool and foundation mix

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swimmingpool and foundation mix

Postby rob28 » Fri Jun 08, 2007 10:47 am

i wondered what the exact mix is for high strenght concrete to be used in a swimming pool and foundations for a 2 storey hous.

i have seen a lot of posts for the c20 mix 1(cement):2(sand):4(gravel)
but i would like to make something stronger.

i saw on the paving expert site two more mixes. c25(1:1,5:3) and c30(1:1:2)
i wondered what would be best to use in thailand . i guess one would start using the red elephant cement.
rob28
 
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Postby jazzman » Mon Jun 11, 2007 9:13 am

Hi Rob,

Thais don't talk 'scientific'.
You just tell them what you want it for and they'll (usually) get you the right thing - they do build houses, even skyscrapers here! There is really no point in wanting something stronger than the strongest mix already available. Remember that an overdose of cement powder can actually weaken the mix (see postings on this).
Send your wife though because if they know there is a farang behind it, it will cost you double. Expect to pay around 2,200 - 2,500 per cu in BKK, Pattaya and Phuket, and 1,400 - 1,700 in the provinces.

It would help to be precise, pool mix and 2-storey house mix are not quite the same thing, so you will find that this board is well organised with dedicated forums for absolute clarity, even if some of the basic information is repeated.

You will certainly be using best quality Portland cement at about 135 baht per 50kg bag for most applications (unless you are on a really tight budget). It's often called 'boon daeng' because the bags usually have red print whatever the brand, and the instructions for each kind of mix are printed clearly, pictographically, on each bag. There are several brands, and this is what you would usually use for load bearing concrete. The price difference per bag for different qualities/brands of cement is so small that it is not worth cutting corners, there is never any harm in using the highest quality for almost any job except rendering - for this there is a special mix.
For floors, driveways and paths and other non load bearing applications, 'boon kiaow' in the green bag - again several brands eg, Sua (Tiger) and TPI - is sufficient and will cost around 115 - 120 per bag. You can also use this if your upstairs floors have prestreesed concrete slabs between the beams for their base.

For pools, don't forget the nam ya (see appropriate postings) and do read the lead article on pool construction and maintenance on this board here:
http://coolthaihouse.com/forum/viewtopic.php?t=645
If you are building the pool yourself, you will certainly save a fortune, but you will save even more if you invest a little in consulting a specialist at some stage of the proceedings who will save you agony, money and disappointment later. A real consultant's fees will be surprisingly low (but not too low, see postings by Nawty on the pool forum) These people will give you a list of consultants in your area whom you can trust implicitly, and their advice is absolutely free: <edit Dozer 7/30/09> , For free, they will also check any prices for you before you buy anything.

Again, please do checkout the other postings on this board and the main site, and of course do post - in the appropriate forum - if you find out something new. :wink: This will probably be up-to-date and regional info on prices, because the products themselves will not change. A good idea is also just to go to a building supplies merchant and wander around in the warehouse and check the stuff out for yourself while all the time asking about prices.

When you have finally got a quote
from your local CPAC depot (because you are NOT going to mix this amount of concrete yourself), please post the results and someone will surely tell you if you are being taken for a ride or not.

Hope all this helps.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
Don't let this happen in YOUR house.
jazzman
 
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Joined: Wed Dec 06, 2006 9:11 pm
Location: Thailand

mix

Postby rob28 » Mon Jun 11, 2007 9:46 am

hello jazzman,

thank you for your reply to my post.
I had been reading almost all of the old postings before i posted my question.
I read them again and i still have some questions. i hope you can help me.
The reason why i posted my question is that on the infobasicmaterials page i read about a "normal " concrete mix which is 2:3:4.it seems unlikely to me that one would use this mix for the whole house including swimming pool.
After that i read an old posting of yours from december 6 , 2006 about the differences in concrete strenght in thailand.
I am planning to build a 2 storey house 2 meters above ground level on pillars.
The location is koh tao so it will be impossible to bring in a cement truck so i will be mixing myself with a cement mixer.
I have been observing a lot of construction work here on the island and i am not impressed with most of the work.

So coming back to my question and with your posting in the back of my mind. do you know the proper mixes for 240 steng and 280 steng concrete?

thanks
Rob
rob28
 
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wrong date

Postby rob28 » Mon Jun 11, 2007 9:57 am

sorry, that old post of your's was on feb 16 2007 but you'll know that already.

Rob
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Postby jazzman » Mon Jun 11, 2007 10:41 am

The strongest mix is usually 7 bags of Portland to each cu.
Give me a couple of hours and I will come back with the spec you require for your Stengs.
Even more important is to get the rebar calculations right.
Pool concrete must have a waterproofing agent added. I specify SILKA which costs 600 baht for a 22 ltr drum. You add 0.42 litre to every 100 kg of cement powder. There is a Thai equivalent called ATM and only costs half - this does not mean it is inferior, but I prefer, for the tiny extra cost (22 ltr is enough for a 4 x 10 pool) to err on the side of caution and recommend an international brand.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
Don't let this happen in YOUR house.
jazzman
 
Posts: 2161
Joined: Wed Dec 06, 2006 9:11 pm
Location: Thailand

Postby jazzman » Tue Jun 12, 2007 5:09 pm

Thai readymix concrete 'steng' specs:

Here is the mix (taken from a previous posting which you may have missed):

The VERY approximate quantities of materials used to generate 1m³ of a C20 (1:2:4) equivalent concrete are.....

* Ordinary Portland cement (OPC) - 350 kg
* Fine aggregate (sand) - 700 kg
* Coarse Aggregate (gravel) - 1100 kg
* Water - 190 kg (190 litres)

Current price variations are for Udon Thani. Mixing proportions for 1 cu are 2 gravel, 1 sand, 6 bags (300 kg) cement. which works out with your "i have seen a lot of posts for the c20 mix 1(cement):2(sand):4(gravel)" because a cu of concrete weights approximately 2,2 tons (with the water). It's exactly as I knew already, but if you want a slightly stronger mix you may achieve this by adding one bag more per cu. For footings and beams I usually do, and I use the 240 'steng'. Never mix concrete any wetter than it absolutely needs to be to fill all the spaces in the aggregate and to flow into the formwork. With the correct proportions of sand/gravel there should be no spaces.
For structural/load bearing elements be sure to buy or hire a vibrator.

ABOVE GROUND FLOORS:180 "Steng" @ B 1,300 - B1,530/cu
Cement: TPI Grade 199 "Green" (you will usually be pouring this over prestressed concrete slabs - pan peun.

ABOVE GROUND COLUMNS/BEAMS: 210 "Steng" @ B 1,500 - B1,580/cu
Cement: Tiger Brand "Green" Boon Kiow

SWIMMING POOLS 1-2 m in depth maximum : 240 "Steng" @ B 1,600 - B 1,690/cu
Cement: TPI Grade 299 "Red" Boon Daeng Portland

MAXIMUM STRENGTH
(strongly recommended for anything approaching 2 m depth pools) : 280 "Steng" @ B 1,700 - B1,730/ cu
Cement: Nok Insi Brand, Diamond Pesch

If the brands stated above are not available, be sure you are getting an equivalent. There is also an international cement spec printed on each bag to verify this.
Bangkok prices could be up to 50% higher.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
Don't let this happen in YOUR house.
jazzman
 
Posts: 2161
Joined: Wed Dec 06, 2006 9:11 pm
Location: Thailand

cement

Postby rob28 » Thu Jun 14, 2007 9:08 am

thanks for the info Jazzman, it is really helpful.
does that mean that the nok insi cement is of higher quality than the tpi grade
299?

Rob
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Joined: Wed May 30, 2007 3:36 pm

Postby jazzman » Sat Jun 16, 2007 5:48 pm

Slightly, yes. But not that it really makes any difference. The peasants up here swear by it, but I guess that's based more on folklore. As I previously stated, more important is the amount and grade of rebar you use.
How to build a $20,000 / £14,000 house and a $???? MOTEL Updated 21 March 09 - with BOQ and costs
Don't let this happen in YOUR house.
jazzman
 
Posts: 2161
Joined: Wed Dec 06, 2006 9:11 pm
Location: Thailand


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