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Cement, Sand And Granite (concrete) Mix Explained - Properties - Nairaland

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Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 2:22pm On Feb 15, 2017
Good Day:
Lets explain concrete mix and how your bricklayer is expected to mix your next foundation / decking.

Most time as Non-Construction experienced house builders, we put our trust on the bricklayers to mix our concrete rightly, however very few of them can be trusted to do the right thing - If your bricklayer negotiated for material and labour (its even more difficult to trust him) because he might be maximizing gain and reducing materials; often times even when you buy your materials; they tend to put in excess sand, granite ratio to minimize time spent in doing the job.

LETS DISCUSS THE BASIC RATIOS AND WHAT IS EXPECTED OF THEM.

We'll start by explaining what the ratio 1:2:4, 1:3:6 etc. means - What this means is the Cement, Fine aggregate and Coarse aggregate ratio. Where fine aggregate could be Sharp Sand or Stone dust and Coarse aggregate could be granite, gravel or stone-base (for certain project types).

1:2:4 therefore means, 1 part of cement : 2 part of fine aggregate : 4 part of coarse aggregate. This 'part' as used refers to volume. It means If I have 1 head-pan of cement, I'll need 2 head-pan of sharp sand and 4 head-pans of granite / gravel or 1 cup of cement, 2 cups and 4 cups respectively of sand and stone.

The above is the theory of the mixture.... but practically on site; their might be need to modify a bit.

Comparing Granite and Gravel:

Granite are basically rocks blasted and keep 'neat' while gravel are rocks that come with a lot of 'dirt' i.e sand. (in my terms) - It means if I have 2 head-pans of granite; I have 2 head-pans of granite but in the case of gravel, if I have 2 head-pans of gravel, what I have is probably 1 head-pan of gravel + 1 head-pan of gravel sand.

The implication is simply:

If I'm working with granite, I can maintain my mix ratios as theory has it but when working with gravel, you are expected to reduce the quantities of sand in it (because gravel itself contains too many sand) so you don't end having too much sand hence the theoretical ratios can't work.

Solution:
The solution to this is by mixing the first bag of cement & aggregate on site and adjusting the quantities accordingly.

Relationship Between Concrete Elements:

CEMENT - SAND - STONE relationship; In practice a 50kg of cement bag contains 2 head pan of cement; this means that if i have a plan to mix 1 bag of cement my mixing ratio would be:

1:2:4 = 1 bag of cement : 4 head-pans of sand : 8 head-pans of stone
1:3:6 = 1 bag of cement : 6 head-pans of sand : 12 head-pans of stone

but must you measure sand and stone in head-pans when you have large quantities to mix?

We have come to conclude also that 4 head-pans = 1 wheel barrow; so for my 1:2:4 mix - I'll have it as 1 bag of cement : 1 wheel barrow of sand : 2 wheel barrow of stone etc.

Over time on site however; you always find the above mix to have too much sand or too much stone....but that doesn't mean the ratios are wrong; IT MEANS OUR MEASUREMENTS ARE NOT ACCURATE - We can only get an accurate mix if we're using a batching plant (off-course not on our little project is this possible)

MY SOLUTION:
I've studied a ratio that works: and that's what I've always recommended on small projects, especially when the Manual Mixers (that mixes half bag at a time) are used.

1:3:3 is that mix.

HALF BAG OF CEMENT : 3 HEAD-PANS OF SAND : 3 HEAD-PANS OF GRANITE and if you're using gravel, you might need to reduce the sand content and increase the stone content to say 1:2:4 etc. mixed with about 30-35 ltrs of water.

Lastly; the other factor that affect this ratio is the size of stone; the smaller the granite size, the more you might need to add eg if I'm using the smallest chippings (1/4) of an Inch; I might need to make my ratio 1:3:4 instead of 1:3:3 to ensure adequate strength.


Lets create a 'healthy discussion' towards ensuring a safe construction practices...


Thanks.


Pics:
1. 1/2 bag Manual Mixer
2. Gravel (It is possible to get 'neat' gravel but most of the ones supplied are local and very dirty with sand here in Lagos)
3. Granite

5 Likes 1 Share

Re: Cement, Sand And Granite (concrete) Mix Explained by slimmdree(m): 3:03pm On Feb 15, 2017
nice write up

1 Like 2 Shares

Re: Cement, Sand And Granite (concrete) Mix Explained by Teewhy2: 6:23pm On Feb 15, 2017
Is the mix same of you are using either gravel or granite
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 7:59am On Feb 16, 2017
Teewhy2:
Is the mix same of you are using either gravel or granite

with gravel u might need to reduce the sand content because the gravel itself comes with a lot of sand....... it is advised to reduce the sand, try a mix with 1 bag to see how it affects the final concrete and stick to what is thought best for the rest of the mix.

Thanks
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 5:23pm On Apr 29, 2017
slimmdree:
nice write up
Thanks.. Appreciate

1 Like

Re: Cement, Sand And Granite (concrete) Mix Explained by ceelog(m): 8:41am On Aug 29, 2017
saydfact:


with gravel u might need to reduce the sand content because the gravel itself comes with a lot of sand....... it is advised to reduce the sand, try a mix with 1 bag to see how it affects the final concrete and stick to what is thought best for the rest of the mix.

Thanks

What are your thought on washed gravel? Say if left under the rain for a few months. Does I make it neater?
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 8:54am On Aug 29, 2017
ceelog:


What are your thought on washed gravel? Say if left under the rain for a few months. Does I make it neater?

If you're buying granite - tell them to make sure i has enough stone. If it doesnt, reduce the sand in the mix..
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 6:51am On Oct 24, 2017
@ DEXTROVERT: this is that article..
Re: Cement, Sand And Granite (concrete) Mix Explained by DEXTROVERT: 6:33am On Oct 25, 2017
saydfact:
@ DEXTROVERT: this is that article..

Thanks boss
But my question is I see angulated rocks pieces not the broken granite used as foundation, I mean rock from which granite is formed, does it have any advantage or disadvantage when used as foundation against mixed cement:sand:granite

1 Like

Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 6:42am On Oct 25, 2017
DEXTROVERT:


Thanks boss
But my question is I see angulated rocks pieces not the broken granite used as foundation, I mean rock from which granite is formed, does it have any advantage or disadvantage when used as foundation against mixed cement:sand:granite

OK... No you can't use rock for foundation.. The gravel rocks u saw were dug out of the ground... We used them for filling and as hardcore after filling..
Re: Cement, Sand And Granite (concrete) Mix Explained by loftyone(m): 9:22am On Oct 27, 2017
Nice write up. Very educating. Please what's the mixing ratio for block making?
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 11:23am On Oct 27, 2017
loftyone:
Nice write up. Very educating. Please what's the mixing ratio for block making?

Thanks sir,

Sincerely i'm not an expert in block making, its formula or mix - whatever info I give on that wld be googled...... I wld try expanding my knowledge that way soon...

1 Like

Re: Cement, Sand And Granite (concrete) Mix Explained by freshpzy1(m): 12:04am On Nov 26, 2017
kudos to u @op
this is very educating
may God bless your knowledge
saydfact:


Thanks sir,

Sincerely i'm not an expert in block making, its formula or mix - whatever info I give on that wld be googled...... I wld try expanding my knowledge that way soon...

kudos to u @op
this is very educating
may God bless your knowledge
Re: Cement, Sand And Granite (concrete) Mix Explained by freshpzy1(m): 12:11am On Nov 26, 2017
pls is hand made blocks good or manageable for bungalow building
just trying to reduce cost ni ooo

can a hand made block be stronger than a fabricated block, when the number of blocks moulded in one bag is smaller in quantity, compared to fabricated blocks?

can hand made blocks be used for one storey building house, since there will be pillars and round linted in the. house?

please ur advice on the three questions

thanks in advance
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 9:07am On Nov 27, 2017
freshpzy1:
pls is hand made blocks good or manageable for bungalow building
just trying to reduce cost ni ooo

can a hand made block be stronger than a fabricated block, when the number of blocks moulded in one bag is smaller in quantity, compared to fabricated blocks?

can hand made blocks be used for one storey building house, since there will be pillars and round linted in the. house?

please ur advice on the three questions

thanks in advance

Morning, Hand made blocks can be stronger than Vibrated blocks if it has a better mix and well done.

Vibrating a block DONT make them strong, using the right cement and sand mixture is what makes a block strong.... whatever method u decide to use, QUALITY and CEMENT/SAND MIX is what you shd monitor.

have u read my other threads in the property section? see my signature. Thanks.

Goodluck...
Re: Cement, Sand And Granite (concrete) Mix Explained by Julivas(m): 11:38am On Nov 27, 2017
Nice one op
Re: Cement, Sand And Granite (concrete) Mix Explained by freshpzy1(m): 5:34pm On Nov 27, 2017
Julivas:
Nice one op
saydfact:


Morning, Hand made blocks can be stronger than Vibrated blocks if it has a better mix and well done.

Vibrating a block DONT make them strong, using the right cement and sand mixture is what makes a block strong.... whatever method u decide to use, QUALITY and CEMENT/SAND MIX is what you shd monitor.

have u read my other threads in the property section? see my signature. Thanks.

Goodluck...

thank......God bless u

I will keep this in mind

I know one day I will be creating a thread for my building.....thanks
Re: Cement, Sand And Granite (concrete) Mix Explained by scrule007(m): 5:47am On Jun 01, 2018
Please how many sqm of floor or spacewill the mix 1:3:3 cover. Thanks.
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 8:24am On Jun 01, 2018
scrule007:
Please how many sqm of floor or spacewill the mix 1:3:3 cover. Thanks.

Hi, your question is incomplete - what you can rather ask is how many bags of cement is required for xyz(m3) - offcourse 1:3:3 can fill as much as you want... grin grin grin

1 Like

Re: Cement, Sand And Granite (concrete) Mix Explained by scrule007(m): 3:28pm On Jun 02, 2018
saydfact:


Hi, your question is incomplete - what you can rather ask is how many bags of cement is required for xyz(m3) - offcourse 1:3:3 can fill as much as you want... grin grin grin

Ok. How many bags for 200m2 .
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 9:11am On Jun 04, 2018
scrule007:


Ok. How many bags for 200m2 .

200m2 is a lot of SqM - Well thats 135 bags if properly mixed or less if not.

Regards
Re: Cement, Sand And Granite (concrete) Mix Explained by Dunamix: 12:15am On Jul 26, 2018
all my going to site, engineers use 1:5:5 or even 1:6:5 I have barely seen them implement standards. what would you say
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 8:09am On Jul 26, 2018
Dunamix:
all my going to site, engineers use 1:5:5 or even 1:6:5
I have barely seen them implement standards. what would you say


why do you think building collapse is on the increase? same reason why after a small rain, the fence begin to fall or the plastered walls begin to powder.

The choices are ours....
Re: Cement, Sand And Granite (concrete) Mix Explained by Clemostica: 11:16am On Jul 26, 2018
Block layers are note engineers, no engineer will accept this concrete mix ratio that is not specified by BS code or SCP or even ASTM. Ask the guy who started this thread to give you the targeted strength of this fake concrete mix on 7 and 28 days, whether he will note fumble around. If you need technical knowledge of quantity calculations, then add me on Facebook @ sylva clement. Thanks
Re: Cement, Sand And Granite (concrete) Mix Explained by Clemostica: 11:20am On Jul 26, 2018
This is how we know the quack engineers, they don't following construction specifications
Re: Cement, Sand And Granite (concrete) Mix Explained by Clemostica: 11:24am On Jul 26, 2018
Hello, which Construction and Specification code is backing this mix ratio of 1:3:3?
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 2:55pm On Jul 26, 2018
Clemostica:
Block layers are note engineers, no engineer will accept this concrete mix ratio that is not specified by BS code or SCP or even ASTM. Ask the guy who started this thread to give you the targeted strength of this fake concrete mix on 7 and 28 days, whether he will note fumble around. If you need technical knowledge of quantity calculations, then add me on Facebook @ sylva clement. Thanks

Clemostica:
This is how we know the quack engineers, they don't following construction specifications

Clemostica:
Hello, which Construction and Specification code is backing this mix ratio of 1:3:3?

see pics below; there is a reason why 'your app' allows for that MIX MODIFICATION - its called RESEARCH...... lol

If you read my post well, I started by listing the standards and then going on to explain what my experience on many sites has taught me; kindly share your knowledge here for every1 to learn rather than inviting us to your facebook page....

THANKS


ALSO READ: http://civilengineersforum.com/concrete-mix-ratio/

2 Likes

Re: Cement, Sand And Granite (concrete) Mix Explained by Naslee(m): 2:01pm On Aug 29, 2018
saydfact:


Pls can u educate us on how to get other grades like 20,25 n 30 grades of concrete



see pics below; there is a reason why 'your app' allows for that MIX MODIFICATION - its called RESEARCH...... lol

If you read my post well, I started by listing the standards and then going on to explain what my experience on many sites has taught me; kindly share your knowledge here for every1 to learn rather than inviting us to your facebook page....

THANKS


ALSO READ: http://civilengineersforum.com/concrete-mix-ratio/
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 1:44pm On Sep 04, 2018
[quote author=Naslee post=70718816][/quote]

OK... SOON
Re: Cement, Sand And Granite (concrete) Mix Explained by phorget(m): 11:49am On May 03, 2019
saydfact:

200m2 is a lot of SqM - Well thats 135 bags if properly mixed or less if not.
Regards
Did you consider the thickness of the slab?
Re: Cement, Sand And Granite (concrete) Mix Explained by saydfact(m): 1:00pm On May 03, 2019
phorget:


Did you consider the thickness of the slab?

afternoon.,, sorry your question isn't clear to me/..kindly ask in full or explain
Re: Cement, Sand And Granite (concrete) Mix Explained by Muyi002(m): 5:06am On May 18, 2019
Please I have three questions, please what quantity of sand, cement and granite/gravel stones will be required
1. To make a pillar that will be between block joining
2. To make lintel on 9 inch block
3. No of cement to lay 100 blocks

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