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AKASHGANGA
CONSTRUCTIONAL MACHINES PVT.LTD.

:: ARTIFICIAL SAND ::

Natural sand are weathered and worn out particles of rocks and are of various grades or size depending on the accounting of wearing. The main natural and cheapest resource of sand is river. Dams are constructed on every river hence these resources are erasing very fast. Now a days good sand is not readily available, it should be transported from long distance. Those resources are also exhausting very rapidly. So it is a need of the time to find some substitute to natural river sand.
The artificial sand produced by proper machines can be a better substitute to river sand. The sand should be sharp, clean and course. The grains should be of durable material. The grain sizes must be such that it should give minimum voids. The presence of clay and silt retards the setting of the cement and makes the mortar weaker and the walls or the slab leaks and holds dampness.

The sand in the mortar does not add any strength but it is used as an adulterant for economy and with the same it prevents the shrinkage and cracking of mortar in setting. The sand must be of proper gradation ( it should have particles from 150 microns to 4.75 mm in proper proprtion) When fine particles are in proper proprtion, the sand will have less voids. The cement required will be less when there will be less void in sand. Such sand will be more economical.
Only sand manufactured by V.S.I. Crusher is cubical and angular in shape. Sand made by other types of machines is flaky , which is troublesome in working. There is no plasticity in the mortar. Hence the mason are not ready to work with machine made crushed stone sand. For the same reason inferior river sand may be used. Manufacturing sand from jaw crusher, cone crusher, roll crusher often contains high percentage of dust and have flaky paricle. Flaky and angular particles may produce harsh concrete, and may result in spongy concrete.
There is standard specification for Fine aggregates (Sand). It is divided in four gradations. Generally known as Zone I, Zone II, Zone III and Zone IV. There is sieve Designation for each grade. Gradation is made as per the use of the sand. There are testing sieves for testing the sand. A set of Sieves with square hole is available. Followings are the sieves

4.75 mm,2.365,1.1830,600 microns,300 microns,150 microns
pan

Specific percentage are designated for each size for each Zone sand in terms of material retained or passed `from the sieves.

• Zone One Sand :

Sieve size	Percentage retained	Percentage passing
4.750	10 %	90-100 %
2.365	40 %	60-95 %
1.1830	70 %	30-70 %
600 microns	66-85 %	15-34 %
300 microns	80-90 %	5-20 %
150 microns	90-100 %	0-10 %

• Zone Two Sand :

Sieve size	Percentage retained	Percentage passing
4.750	10 %	90-100 %
2.360	25 %	75-100%
1.1830	45 %	55-90 %
600 microns	41-65 %	35-59 %
300 microns	70-92 %	8-30 %
150 microns	90-100 %	0-10 %

Where concrete of high strength and good durability is required Sand used should be of proper gradation. The concrete mix design should be done properly. When the sand of finer grade is used, the ratio of finer to coarse aggregates should be reduced. The fine to coarse ratio depends upon the particle shape, surface texture of both fine and coarse particles. The gradation of coarse and fine aggregate is very important. Very fine sand is not recommended for concrete purpose.
The fines content in the sand below 600 microns should be about 30 to 50 %. This will be a ideal sand for concrete work as well as masonry and plaster work.
At present it is generally observed that the fine content in river sand below 600 microns are very less. Such sand should not be used for concreteing work.

Our Rotopactor Produces perfact sand of required gradation. Sand of any Zone can be produced. Sand from our Rotopactor is a perfect substitue for river sand.

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