Sir, Why theoretical concrete quantity is more than actual poured qty if there is mass concrete or by mechanical concrete ??
Why theoretical concrete quantity is more than actual poured qty if there is mass concrete or by mechanical concrete
- Thread starter Amit Baluni
- Start date
Ur theoretical concrete quantity never accounts for volume reduction of reinforcement in case of mass concrete & wastage during pouring.
thanks sir for your reply but can you explain more points which also effect.
Dnyan Deshmukh
Staff member
Factors that affects the concrete quantity in practical application.
Yield of the concrete = it is like after mixing ingredients as per design, do am i getting volume of concrete equals to 1 cum or is there any difference.
This volume gets affected due to change in source of the aggregates, if aggregates becomes lighter in density, your concrete is going to give you more than a cum in volume for same mix design. it will further reduce the volume of the concrete in case of aggregates received are heavier than one used for doing mix design.
Batching Error - The batching plant if looses its calibration on its weight scales, it will impact severely on a produce concrete like it will overdose the aggregates in a mix which will tend to increase the volume of 1 cum of concrete with same cement content.
Error in Theoretical Concrete Quantity Calculations - This will also lead to difference between poured and theoretical quantity either on plus or on minus side.
Pouring Error - In case of the mass concrete pouring less by few mm or few cm could make a huge difference in the concrete quantity which in most of the cases results in consumption of concrete by less than required amount as per theoretical value.
Yield of the concrete = it is like after mixing ingredients as per design, do am i getting volume of concrete equals to 1 cum or is there any difference.
This volume gets affected due to change in source of the aggregates, if aggregates becomes lighter in density, your concrete is going to give you more than a cum in volume for same mix design. it will further reduce the volume of the concrete in case of aggregates received are heavier than one used for doing mix design.
Batching Error - The batching plant if looses its calibration on its weight scales, it will impact severely on a produce concrete like it will overdose the aggregates in a mix which will tend to increase the volume of 1 cum of concrete with same cement content.
Error in Theoretical Concrete Quantity Calculations - This will also lead to difference between poured and theoretical quantity either on plus or on minus side.
Pouring Error - In case of the mass concrete pouring less by few mm or few cm could make a huge difference in the concrete quantity which in most of the cases results in consumption of concrete by less than required amount as per theoretical value.
Sumathi chowthri
Newbie
sorry if am wrong sir...density of aggregate or cement doesn't matter in the sense of concrete volume variation b/w Theoritical vs actual i guess. It may correct during the output volume of concrete from batching plant.
Dnyan Deshmukh
Staff member
By stating density, I mean to say specific gravity in simplest way.
Specific gravity of the material do impact on the volume of the concrete produced, in case when the concrete production is done by weight batching process.
At the time of concrete mix designing, the weights of the each aggregates are decided base on their specific gravity.
Specific gravity is the ratio of per unit volume of material compared with same unit volume of water (stating it with unit of kg/cum does not make any difference like, aggregate having specific gravity of 2.9, I could say aggregates weights 2900 kg per cum in its purest form without any voids in it, but as its a ratio in mathematical calculations kg and cum get removed).
crush aggregates when taken as cum quantity, it will weight less due to presence of voids in it, if we compare it with same aggregate / rock which is in size of 1m x 1m x 1m.
example - I have to put 750 kg of 20 mm aggregates in concrete. if its specific gravity becomes low due to higher porosity or voids in it. the volume which it makes to same weight will get increase and will make my concrete more than a cum for same mix design. same way if its specific gravity increases my volume will become less for same required weight of aggregate in mix, this will result into less volume of concrete.
Heavy weight concrete is produced by using heavy aggregates where the volume of the concrete is same but weights of aggregates are more.
so changes in specific gravity of aggregates do impact on the volume of concrete produced with it.
Specific gravity of the material do impact on the volume of the concrete produced, in case when the concrete production is done by weight batching process.
At the time of concrete mix designing, the weights of the each aggregates are decided base on their specific gravity.
Specific gravity is the ratio of per unit volume of material compared with same unit volume of water (stating it with unit of kg/cum does not make any difference like, aggregate having specific gravity of 2.9, I could say aggregates weights 2900 kg per cum in its purest form without any voids in it, but as its a ratio in mathematical calculations kg and cum get removed).
crush aggregates when taken as cum quantity, it will weight less due to presence of voids in it, if we compare it with same aggregate / rock which is in size of 1m x 1m x 1m.
example - I have to put 750 kg of 20 mm aggregates in concrete. if its specific gravity becomes low due to higher porosity or voids in it. the volume which it makes to same weight will get increase and will make my concrete more than a cum for same mix design. same way if its specific gravity increases my volume will become less for same required weight of aggregate in mix, this will result into less volume of concrete.
Heavy weight concrete is produced by using heavy aggregates where the volume of the concrete is same but weights of aggregates are more.
so changes in specific gravity of aggregates do impact on the volume of concrete produced with it.
Dnyan Deshmukh
Staff member
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