concrete mixing ratio

[UltimateCustomizing]

Could anyone inform me as to what is the correct mixing ratio for concrete .
Most builders told me 3:1 but is it ;

3 part gravel to 1 part cement

or

3 part gravel to 1 bag cement

[janfar]

Most builders use the ratio of 3 wheel barrows to 1 bag of cement... this seems to be a common thing and gives you a standard finish WRT houses etc...

[X_Factor]

depends on what ur casting
if its for foundations or structural work( posts, ring beam decking etc, some ppl go a bit stronger at 5 barrows of gravel to 2 bags of cement

if its for flat driveways or not as important things they use the 3 to 1 or may even push it a bit more

[pugboy]

what is most important is the water
too many people make it soupy and couple years later want to know why the concrete wearing away and weak

[Rory Phoulorie]

Could anyone inform me as to what is the correct mixing ratio for concrete .
Most builders told me 3:1 but is it ;

3 part gravel to 1 part cement

or

3 part gravel to 1 bag cement

What 28 day concrete compressive strength (cube or cylinder) do you need? That will determine the appropriate proportions. Trinidad Cement Limited has a small brochure with different mix designs depending on the concrete strength you require.

[shaneelal]

Could anyone inform me as to what is the correct mixing ratio for concrete .
Most builders told me 3:1 but is it ;

3 part gravel to 1 part cement

or

3 part gravel to 1 bag cement

What 28 day concrete compressive strength (cube or cylinder) do you need? That will determine the appropriate proportions. Trinidad Cement Limited has a small brochure with different mix designs depending on the concrete strength you require.

See here for part of brochure:

http://www.tcl.co.tt/resources/resource.asp?id=7772

[zcarz]

preheat at 350F and bake for 30 mins

[SMc]

how big is a part of gravel?

[matthewmazda]

Most builders use the ratio of 3 wheel barrows to 1 bag of cement... this seems to be a common thing and gives you a standard finish WRT houses etc...

x2

[Rahtid]

Could anyone inform me as to what is the correct mixing ratio for concrete .
Most builders told me 3:1 but is it ;

3 part gravel to 1 part cement

or

3 part gravel to 1 bag cement

What 28 day concrete compressive strength (cube or cylinder) do you need? That will determine the appropriate proportions. Trinidad Cement Limited has a small brochure with different mix designs depending on the concrete strength you require.

This we know, but I dont think he is building something that costing a mil or over,,,otherwise he would've gone with premixed concrete and get all the details and documentation.

Pal, I would say use the mixture everyone here is saying 3:1 which is normally 3 barrows of gravel to a bag of cement, and you can always throw in a few bags depending on how the texture/color is. If you are casting a deck or some structural element,,dont use the 3:1,,more like 5 barrows to 2 bags cement,,are you using any hardener?

If this is who I think it is,,,call me nah,,I would pass and check yuh,,

[ssaroop]

There are several grades of mixes; A to E. (These ratios are for hand mixed). For exposed/coastal concrete we use (2:3:4) grade A, i.e. 2 bags cement, 1.5 w/barrow sand, 2 w/barrow gravel, 2 buckets water. For beams or columns we use (1:2:2) grade B, i.e. 1 bag cement, 1 w/barrow each of sand and gravel, 2 buckets water. For Slab and protected concrete we use (1:2:3) grade C, i.e. 1 bag cement, 1 w/barrow sand, 1.5 w/barrow gravel, 2 buckets water. For Foundations we use (1:2:4) grade D, i.e. 1 bag cement, 1 w/barrow sand, 2 w/barrow gravel, 3 buckets of water. For backfilling or blinding concrete we use (1:3:6) grade E, i.e. 1 bag cement, 1.5 w/barrow sand, 3 w/barrow gravel, 5 buckets water. The strengths in N/mm squared are grade A - 30, grade B - 28, grade C - 26, grade D - 21 and grade E would be rated nstr (non-structural concrete). Please note also that the volume and quality (clean) of water is very important to achieve the strengths. The sand I refer to is sharp sand and the gravel is basically washed gravel either 3/8" or 1/2" or 3/4" (depends on use). Please review the Small Building Guide recently published by the TTBS for all information regarding construction of small residential and commercial buildings available at the government printery. Also beware of some 1/2 and 1/2 gravel being sold that are rated non concrete gravel because it does not cure and bind, you have to trust the source/pit where your driver brings it from.

[MG Man]

There are several grades of mixes; A to E. (These ratios are for hand mixed).
For exposed/coastal concrete we use (2:3:4) grade A, i.e. 2 bags cement, 1.5 w/barrow sand, 2 w/barrow gravel, 2 buckets water.

For beams or columns we use (1:2:2) grade B, i.e. 1 bag cement, 1 w/barrow each of sand and gravel, 2 buckets water.

For Slab and protected concrete we use (1:2:3) grade C, i.e. 1 bag cement, 1 w/barrow sand, 1.5 w/barrow gravel, 2 buckets water.

For Foundations we use (1:2:4) grade D, i.e. 1 bag cement, 1 w/barrow sand, 2 w/barrow gravel, 3 buckets of water.

For backfilling or blinding concrete we use (1:3:6) grade E, i.e. 1 bag cement, 1.5 w/barrow sand, 3 w/barrow gravel, 5 buckets water.

The strengths in N/mm squared are grade A - 30, grade B - 28, grade C - 26, grade D - 21 and grade E would be rated nstr (non-structural concrete).

Please note also that the volume and quality (clean) of water is very important to achieve the strengths.

The sand I refer to is sharp sand and the gravel is basically washed gravel either 3/8" or 1/2" or 3/4" (depends on use).

Please review the Small Building Guide recently published by the TTBS for all information regarding construction of small residential and commercial buildings available at the government printery. Also beware of some 1/2 and 1/2 gravel being sold that are rated non concrete gravel because it does not cure and bind, you have to trust the source/pit where your driver brings it from.

[Bizzare]

what is most important is the water
too many people make it soupy and couple years later want to know why the concrete wearing away and weak

who removed my reply to this.

[MG Man]

somebody piss on it

[Nighttroll]

The 1/2 and 1/2 being sold are generally smooth pebbles. Ready mix uses crushed stone that has an irregular shape. Because of this, the compression strength is much more with the crushed stone.
Try to get crushed stone instead.

[UltimateCustomizing]

[quote="Nighttroll"]The 1/2 and 1/2 being sold are generally smooth pebbles.


This is an important factor i was looking at .

[X_Factor]

^ ru building a house or something else?