Birla 53 grade "cement:sand :aggragate : ratio"

[velu]

Hi

Can someone tellme the ratio of cement+sand +20mmjally( aggargate) for Columns concrete: lintel concrete: roof concrete:Chajja
In what ratio they should be mixed..

Iam buying Birla 53 grade


Thanks
velu

[m3_07]

Concrete mix - Ratio - 1:2:3 (cement:Jalli:Sand)
Inside palstering - Ratio - 1:6 (cement:Sand)
Outside plastering - Ratio - 1:4 (cement:Sand)

More details - Check Bharti Cements website technical section.

[velu]

thanks

[ardesarchitects]

Hi Velu
Concrete mix is mentioned in the structural details as m15/m20/m25 etc....
M-15 = 1:2:4 (cement:sand:stone aggregate)
m-20= 1:1.5:3 (cement:sand:stone aggregate)
m-25= 1:1:2 (cement:sand:stone aggregate)
Depending up on the slab spans ,beam lengths,loads etc..civil engineers design the concrete mix.In general constructions M20 is good enough.

Regards
Ar.Praveen.N
Ardes Architects and Interior Designers
www.ardesarchitects.com

[sk1976]

Hi
I was told that 1:1.5: 3 ratio of m20 has

1 unit of cement
1.5 unit of sand and
3 unit of 20 mm jalli

But I see that in above posts, the order is reversed. i.e. 1.5 unit of Jalli and 3 unit of sand.

My contractor follows the following proportion for all concreting works

1 bag of cement -> has 4 pots of cement
10 pots of river sand
10 pots of 20 mm jalli
4 pots of 12 mm jalli

So the resultant mix is 1(cement):2.5(sand):3.5(Jalli) and he says most of the contractors use 1(cement):3(sand):4(jalli). Birla super 53 grade OPC is used.

Is this acceptable structurally and is this a common practice ?

Thank you,
Selva

[BengaluruBoy]

MK, most of the contractors use the proportion as you mentuoned. They did the same thing in our ongoing project too. I noticed that and brought it to the notice of my architect. This proportion is not correct. I asked my contractor to follow the correct proportion or quit. He has changed the mixing proportion since then and I see a better quality concrete now visually too. Even though he says he is following the instrction I think he has changed only little bit.

So, please ask him to go with propoer M20 specification.

[JollyRogers]

During the RCC roofing recently my contractor was using 9 pots of sand and 10 pots of 20 mm Jalli for 1 bag of Cement. Going through the post, I see that its not the optimal mix.
I just saw this inormation in the Bharti Cement Technical support section: "Concrete: The ideal ratio of the concrete mixture should be 1:1½:3 (1 cement: 1½ sand:3 aggregate)." which might be incorrect as everywhere else I see the ratio as 1:1.5 Stones and 3 Sand, and also as indicated by Ar.Praveen.N..
For RCC I was using ACC Concrete Plus cement. Is the mixing ratio different for different brands of cement? Can anyone please shed some more light on this topic?

[akula]

One of my architect friends says , 1:1.5:3 / 1:2:4 refers to cement : sand : jalli. I also checked with some contractors who agree with it. Praveen should pls clarify.

[ardesarchitects]

Hi,
Its my typo mistake in the previous post,sorry about it.Hope i haven't damaged some ones work.
The ratio is always cement :Sand :jalli
M20 in theory its - 1:1.5:3 but in practical they make 1:2:3 to avoid honey combs .Less the sand more the honey combs .The jalli will not settle properly in case of less sand.

Regards
Ar.Praveen.N
Ardes Architects and Interior Designers
www.ardesarchitects.com

[sam_m400]

I am not getting clear as it states we need to use M20 mix for RCC, but about others like

1. Columns mix + with size of steel to use
2. Beams mix + with size of steel to use)
3. lintel concrete + steel size to use:
4 .roof concrete : Already mentioned (M20 proportion) but can anybody mention the size of steel to use -
5.Chajja Mix :
6.internal flooring (Any steel to use)
7.External flooring. (any steel to use)
8.Belt mix for foundation with size of steel to use ( if brick foundation is not used only Belt foundation)

Anybody please give the same as it would help everybody to propose this model