The two different ways in Concrete Proportioning Mixture:
1. Volume Method
2. by Using Mixturing Box.
Volume Method is the most common and convenient method in Mixing Concrete to attained the desired strength of concrete.Concrete misture, it involves cement, sand and gravel. Proportioning by Volume method had been long practiced and it is proven effective and successful. Most construction industry used this method in proportion the mixture of the concrete. see tabulation below about the ratio of the cement sand and gravel mixture.
Mixture class Proportion Cement in bag sand gravel
40kg 50kg cu.m cu.m
class AA 1 : 1 1/2 : 3 12 9.5 0.5 1.0
class A 1 : 2 : 4 9.0 7.0 0.5 1.0
class B 1 : 2 1/2 : 5 7.5 6.0 0.5 1.0
class C 1 : 3 : 6 6.0 5.0 0.5 1.0
Strength of Mixture
a. Class AA - 4000 PSI
b. Class A - 3500 PSI
c. Class B - 3000 PSI
d. Class C - 2500 PSI
Mixture of half cubic meter sand, a cubic meter of gravel and a portion mixture of cement depending on the class that you are using and plus water, there will be a little bit more than one cubic meter of volume,this will serve as contingency or wastage.
29 Comment:
I am trying to ascertain the mix design for a 3500psi concrete. Based on your chart above the mix ratio for this design is 1:2:4
Will this hold true for all instances of a 3500psi concrete, regardless of the properties of the materials being used? ie sand, cement and gravel?
the design strength of the concrete will be realize if you will use Portland Cement, and any properties for sand and gravel, the proportion must be accurate to achieve the design strength. this will have a curing of 28 days.
thanks for the comment.
i would like to know what will be the design thickness of the slab and the wall intended for an open rectangular tank that would carry a 25 cubic meter volume of water. The water is coming from a pool in order that it will be recycled for further use.
Thanks
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The design thickness of the slab and the wall will varies with the depth of the tank, the deeper, the biggest pressure that you may obtain from your analysis.
There are lot of software that you can use. like staad(finite element) to know the contour stresses of the wall then you can use that stresses to compute the number of rebars on that particular concrete wall and slab or you can use safe, This software automatically generates the number rebars needed.
for further assistant you can email me: engredwin@emarinduqueengineers.com
Pls how do i knw the volume sand,cement n gravel in 1500m3 concrete lintel
let us assume that the strength of the lintel concrete is class A, just multiply the proportion value that I've listed above
Example
Cement : 1500cu.m X 9 =13500 bags of cement
sand : 1500cu.m X 1 =1500cu.m sand
gravel : 1500cu.m X .5 =750 cu.m gravel
These are the theoretical value to complete the 1500 cu.m concrete lintel
I have a project which is design for 3000 psi, yet our mixture is 1:2:4 , now that we had taken samples on it, it only reaches 2000 -2200 psi. How come would that be? we use truck mixers for mixing since we our now in pouring 3rd floor slab. Can you help me with these? Tnx
It could be a failure in the water-cement ratio which is critical in any concrete mix or maybe your aggregates are not washed.
yeah, I agree on that, water-cement ratio will really matters. It controls the strength, durability and water tightness of hardened concrete and too much water will weaken concrete after curing. The strength of the concrete increase if it has smaller water cement ratio.
Thanks for the advise anonymous
"It could be a failure in the water-cement ratio which is critical in any concrete mix or maybe your aggregates are not washed."
4000psi strength seems so weak. some reported concretes have strengths which could reach 29000 psi.how is that so?
what value of water cement ratio must be used in class B mixture?
You can use average water - cement ratio, 6 gallons per 40 kg bag of Cement.
how can i calculate the needed materials given the dimensions of the area which is 20x36 m and the thickness is 5"?
what would be your desired strength,? anyway you can just multiply the volume directly to the concrete mixture ratio, for example:
If your desired strength is Class A mixture, you can apply this computation
Cement : 1cu.m X 9 =9 bags of 40kgs-cement
sand : 1cu.m X 1 =1cu.m sand
gravel : 1cu.m X .5 =.5 cu.m gravel
correction
sand: (c/v) x 0.5
gravel: (c/v) x 1
not the other way around
but i doubt if its accurate since you apply this factor to all cement ratio
sand and cement factor should differ in every cement class
does isn't affect the volume if you add water?
In comparing class AA with class A which of the 2 mixture of specifications is stronger and more durable and lasting?
Theoretically speaking class AA is much stronger compared to class A, but it all depend on the water cement ratio,
factors above are used only for estimate purposes
You have already explained the computation for the required materials but you haven't included the required water. How do you compute for the required water you should use for class a, b or c mixture?
what concrete ratio of cement water gravel are needed to achieve 6000psi strength and 7500psi strength?
Just a question, it is possible to have exact 2 different slump test measure for only one design like 2500 psi. thanks!
Dear what would be the concrete mixture ratio for hollow wall panel (carrying no loads, just like a beick, but in a panel 600mmx150mmx3000mm high
Thanks
Dear fellows, what standard reference code where to find these concrete proportions class "AA, A, B & C" as a basis, is it stated in any American standard code or any international standard code?......
what is the concrete mixture for 30N/mm2? does this mixture fall on the ratio of 1:1.5:3 of class AA? i need your help. thanks.
is 1:2:3 ratio the same as 9bags, 0.5cu. m sand, 1cu m gravel?
May I know the volume of water on the different classes of mixture. I'm an architectural student. Ty
what is the value of 170 kg/cm2/mm when covert to MPA and how to convert it
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