Concrete

[KhaoYai]

I've never done any 'wet' work in Thailand but I will be doing in a few weeks so have a few questions:

 

I will be constructing a concrete base for a 1500 - 2000L water tank and pump at a friend's house in Korat. In the UK for such a small quantity we would mix it on site and for the strength I need, I'd guess a 1 cement, 3 sand, 3 aggregate mix keeping it as dry as possible whilst workable.  Are these mixing ratios the same in Thailand? I'd actually prefer to buy readymixed concrete but I suspect that there will be a minimum delivery that is far above the quantity I require.  I don't have a tub to mix it in though so by the time I've bought that, it may be better to suffer the minimum delivery - any views? I guess I could find a use for the remainder in any case.

 

Also, I'm used to digging down to clay and then back filling with reducing grades of rubble/aggregate, compacted in order to form a base for concrete.  I suspect I could be digging a long time to reach clay in Thailand - if ever. I'm not constructing a motorway so I guess the Thai way is OK.  This would be - dig out around 300mm of soil and backfill with rubble then compact?

 

Not so much for this job but out of interest, given that its so hot, does Thai concrete/cement already include a retarding agent or are these added later?

[jvs]

Does not sound like a very big job,less than a sqm?

1 cement,2sand 3gravel.

if 1sqm=1x1x.1 is 100 liters.

I would not even dig very deep,maybe take the sod dept out and

then place plastic on the bottom.

Use 10 cm wide boards and maybe put some steel to reenforce it.

mix in wheelbarrow,done within an hour.

[eyecatcher]

You only need just over half a cube if you make a base 2mx2mx150thick so no point paying for cubes not carried.

It will take you a day thats all, a hard day.

Its carrying 2tons of water so it needs to be right, I would throw some steel mesh in to give your mixing some extra confidence.

Then again, to buy a mixi g tub will set you back 500bt but you have it for the next job.

Your mix is a bit weak, general concreting mix is 1:3:6 but for a stronger mix 1:2:4 is the most common.

Dont hand mix it too dry, you will never move it, the key is to make it manageable without being sloppy and quickly move it into position.

Have some polythene or shadi g handy to keep the sun off it.

[Denim]

 

You can buy ready mix cement in bags here. Just need to buy the aggregate. 

 

As for clay , depends where you live. We are in lower Petchabun and have clay on the surface. Our cesspits are 4 rings deep ( about 8 feet ) and its clay all the way.

[eyecatcher]

3 minutes ago, jvs said:

Does not sound like a very big job,less than a sqm?

1 cement,2sand 3gravel.

if 1sqm=1x1x.1 is 100 liters.

I would not even dig very deep,maybe take the sod dept out and

then place plastic on the bottom.

Use 10 cm wide boards and maybe put some steel to reenforce it.

mix in wheelbarrow,done within an hour.

You can come and help me next time.....obviously you are not speaking from experience

[Kwasaki]

1 hour ago, eyecatcher said:

You can come and help me next time.....obviously you are not speaking from experience

He is speaking experience it's not a big job first light before getting hot job done.

Mix cement in a wheelbarrow or on a ground surface.

 

[Lacessit]

Heat is only the enemy of strength in terms of evaporation. Cover with sacking and keep the sacking wet. Allow 2-3 days for carbon dioxide to develop maximum strength before placing any load. I'd agree some steel mesh would make for a more professional job.

 

[KhaoYai]

1:2:3 is pretty standard in the UK for general work but I accept that due to the weight 1:2:4 may be better. I was more interested in the base preparation. As the area is so small and there'd be no movement I don't think re-inforcing mesh is a must but for what it costs, it can't harm.

5 hours ago, Denim said:

Our cesspits are 4 rings deep ( about 8 feet ) and its clay all the way.

Which reminds me of a question I've been meaning to ask for a while.  I live in the sticks in the UK so no mains sewerage - much the same as my house in Thailand but I am not sure what system I have there.  In the UK most houses that are not connected to mains sewers use a Septic Tank - which is different to a Cesspit.  A Cesspit requires emptying regularly whereas a Septic tank, in theory, should rarely need emptying as it breeds bacteria which break down the solid matter and the resultant waste water is disposed of by a soak away. I say 'in theory' because they never work 100% due to modern bleaches and detergents but still, I get away with having mine emptied every 3 or 4 years.

 

However, I don't know what type of tank I have in Thailand and nobody local seems to understand what I'm getting at.  There is no cast iron lid like I have in the UK - just a small pipe sticking out of the ground - I'm not there right now but from memory, I'd guess that's around 100mm in diameter.  I've lived there almost 5 years, granted not all the time, and its never been emptied.

 

Does anyone know what type of tank is the norm in Thailand, I'm guessing its a Cesspit and the pipe is to facilitate emptying but there must be a soak away somewhere - even with my intermittent residence, the water, if not the solids, would have overflowed by now if there wasn't. So if it is a Cesspit I'll have to get it emptied I guess. Maybe the Thai system is a sort of 'Hybrid' of the 2 types?

[sometimewoodworker]

You probably have several rings of concrete sunk into the ground. If they never get rain water in them they may never need pumping. In one house ours have gone 10 years and no sign that they need pumping. 

[MikeN]

14 hours ago, Denim said:

 

You can buy ready mix cement in bags here. Just need to buy the aggregate. 

 

For small jobs you can also buy dry concrete mix in 50kg bags, no need to get the aggregate separately.

ie TPI M401, M402, M403, M404 depending on the project and the ksc required.

[David B in Thailand]

To the OP: Is the concrete base for ONLY the water tank or will he have a water pump or water filters near by? Mike N: What store has in stock the TPI M401, M402, M403, M404?  Those are fairly progressive stores to stock such an item in Thailand, certainly rare in Isaan. 

The OP need only walk into any Global House Store, Thai Watsadu store, Home mart store to see a good selection of black or grey proper septic tanks. Some models have a few more features and a better lid system. Cess pit is not a course of action I would take. Septic Tanks sold by DOS, SAFE or Cotto need not be expensive. Those three brands have printed instructions for your Thai home builders to read in Thai with plenty of drawings they can understand. 

[Tanoshi]

On ‎5‎/‎7‎/‎2019 at 1:00 AM, KhaoYai said:

1:2:3 is pretty standard in the UK for general work but I accept that due to the weight 1:2:4 may be better. I was more interested in the base preparation. As the area is so small and there'd be no movement I don't think re-inforcing mesh is a must but for what it costs, it can't harm.

Take the advice of @eyecatcher.

1:2;4 mix at least 150mm deep and lay cross bars of 4mm steel in the base.

This will help to spread the load and prevent sinking.

A Litre of water weighs I kg.

When full that water tank will weight 1.5 - 2 ton.

[Tanoshi]

On ‎5‎/‎7‎/‎2019 at 1:00 AM, KhaoYai said:

Does anyone know what type of tank is the norm in Thailand, I'm guessing its a Cesspit and the pipe is to facilitate emptying but there must be a soak away somewhere - even with my intermittent residence, the water, if not the solids, would have overflowed by now if there wasn't. So if it is a Cesspit I'll have to get it emptied I guess. Maybe the Thai system is a sort of 'Hybrid' of the 2 types?

It could be a self made cesspit with a soak away (or not).

More recently probably a septic tank with a soak away.

Both if installed should have an access cover, but quite frequently these are covered when concreting or tiling outside areas. The fact you have a blue pipe sticking up suggests the original access point has been raised at some point.

 

Take a long dry stick or length of blue piping and insert down into the tube, then withdraw.

This should tell you the depth, how full it is and what's in there!