CALCULATION OF ONE CUBIC CONCRETE MATERIAL
The calculation of material needed to produce one cubic concrete is an integral part of every engineer. Most especially, the civil engineer and the builders, Ignorant of this makes you worthless in the field as the field demand accuracy of such calculation. This article is targeted at given a quick and brief method of carrying out this calculation without stress.
As we all know, concrete is a mixture of cement, sand and coarse aggregates. You will agree with that, when these components are mixed together, there will be voids due to their coarse nature. On these bases, the ancient civil engineers and scientist carried out some trial mixt and come up with the conclusion that in every one cubic meter (1m3) of a wet concrete, the volume decrease by 52% to 54% due to the void in the dry state.
ELIMINATION OF THE VOIDS
To eliminate this shortage, it is there said that, the volume of every one cubic meter (1m3) Dry concrete should increase by 52% to %54% to cover the shortage. Therefore, to achieve one cubic meter (1m3) of concrete by volume, the dry volume will be either (1.52m3) or (1.54m3) multiply by the wet volume (safety factor x wet volume of concrete). This number is therefore called shrinkage or safety factor of concrete. Good knowledge of this factor is what gives quick access to the calculation of quantity of materials needed for the production of a given volume of concrete.
CALCULATION OF MATERILS FOR (1M3) OF CONCRETE
To calculate the materials needed to produce one cubic meter, the following must be born in mind.
- Density of all the materials: cement = 1440kg/m3, sand = 1600kg/m3, coarse aggregate = 1600kg/m3.
- Volume of a 5okg bag of cement = 0.0347 ~ 0.035m3
- Sand and coarse aggregate dumpers are measure in meter cube and tones. 1000kg = 1tone
Haven born the above points in mind, let’s go to the calculation of the material needed to produce (1m3) of concrete.
Safety factor =1.52
Volume of wet concrete = (1m3)
dry concrete volume (safety factor x wet volume) 1.52 x 1 = 1.52m3
Total volume wet concrete require = 1.52m3
Mix ratio = 1: 1.5: 3
Sum of ration =1+1.5+3 = 5.5 therefor,
Volume of cement required = 1/5.5 x 1.52 = 0.1818 x 1.52 = 0.276m3
Volume of one bag of 50kg of cement = 0.035
Quantity of cement require =0.276/0.035 = 7.88 ~ 8bages of cement.
Volume of sand require = 1.5/5.5 x 1.52 = 0.2727 x 1.52 = 0.415m3
Density of sand = 1600kg/m3
Mass = 1600 x 0.415 = 664kg = 0.7tones
Volume of coarse aggregate = 3/5.5 x 1.52 = 0.5454 x 1.52 = 0.829m3
Density of aggregate = 1600kg/m3
Mass =1600 x 0.829 = 1326.4kg = 1.3tones
For every one cubic meter of the mix ratio 1: 1.5 :3
Quantity of cement = 8 bags = 400kg
Sand = 0.415m3 = 664kg = 0.7tones
Stones (coarse aggregate) = 0.829m3 = 1326.4kg = 1.3tones