17-12-2012, 06:00 PM
ARTIFICIAL SAND
1ARTIFICIAL SAND.PDF (Size: 331.93 KB / Downloads: 714)
INTRODUCTION
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
Comparison of artificial sand with river sand
Sand manufactured by Vertical Shaft Impactor is of cubical shape. Such sand can be used for all types of
construction work, Concreting, Plastering etc and is better substitute to river sand.
Followings are the actual result of Concrete Designed with river sand and Artificial sand. proportions are
by weight Mix Design M 15 M 55 concrete is designed for River sand and artificial sand. Results are as
follows:
1) With using River sand :
• Cement one bag ……….. 50 Kg
• Sand 135 Kg
• Agg. 20 mm 135 Kg
• Agg. 12 mm 67.5 Kg
• Water 27.5 ltrs
Strength achieved after 7 days curing………..174.81 Kg/Cmsq.
2) With using Artificial sand : Proportions are by weight
• Cement one bag 50 Kgs
• Sand (artificial m/c made) 125 Kgs
• Agg. 20 mm 137 Kgs
• Agg. 12 mm 75 Kgs
• Water 27.5 Ltrs
Strength achieved after 7 days curing …….186.67 Kg / Cmsq.
Similar test is performed with higher grade Concrete Mix Design M 55
M 55 concrete is designed for River sand and artificial sand.
Conclusion:
From the above design results it can be observed that the strength of Concrete increases with Artificial
Sand. More over the presence of Fines in artificial sand increases the workability and gives more sound
Concrete. The slabs, using Artificial sand, are more leak proof than by river sand.
Now a days, in construction of roads, buildings, dams, canals, etc., cement concrete plays an important
role. Concrete is an artificial stone resulting from hardening of rationally chosen mixture of binding
material, water and aggregate (Sand and crushed stone or gravel). The mixture of these materials, before
it hardens, is called concrete mix. Particles of sand and crushed stone from a stone are car-cass in
concrete. Cement paste resulting from the interaction of concrete mix with water coating on the grains of
sand and crushed stone, fills the voids between them, lubricates the aggregate and imparts mobility
(fluidity) to the concrete mix. When the cement paste hardens, it binds the aggregate into an artificial
stone or concrete.
High quality concrete mixture may be produced only with deep knowledge of all manufacturing procedures, a
proper choice of quality constituents and their optimum ratio, suitable procedures for preparing concrete
mixes, for placing, compacting and hardening them in order to obtain concrete structure of high quality, high
strength, durability and low cost.