River sand is found naturally on river banks having a smooth texture. This sand was widely used as a good combination for making concrete and mortar. It was the cheapest resource of sand, but now its seasonal and sand mining is banned now at many states of india.
The best part about river sand is its capability to refill itself. It can be combined with gravel, cement, steel, and water for the purpose of making concrete. Not only this, river sand can also make mortar for plastering and filling joints by using water and cement.
Manufactured sand (m-sand) is made by crushing granite rocks into small particles. Due to the fast growing construction industry and reduction of river sand, the demand for m – sand has increased. The cost of m-sand is almost 50% less than the cost of river sand.
The best part about m-sand is its easy availability, better quality and less transportation cost. As, m-sand is processed from good quality of granite, it has balanced properties for construction of concrete structures. This characteristic of m-sand helps the concrete structures to withstand extreme environmental condition and prevents steel from getting rusted by reducing absorbency, moisture access, freeze – melt effect which increases the durability of concrete structures.
|Parameters||M (manufactured) sand||River sand|
|Source||Available at quarry and factory||Available at river bed or river bank|
|Procedure||Artificially manufactured.||Available naturally on river banks.|
|Shape and texture||Angular with rough texture. Angular aggregates demand more water.||Better shape with smooth texture. Demands less water.|
|Moisture content||Only water washed m – sand contains moisture so concrete mix is not afected.||Moisture is trapped between the particles which affects mixpropotion in concrete.|
|Bulkage correction||There is no need of bulkage correction during mix design||Bulkage corrections has to be made during mix design.|
|Setting time||Setting time of concerte is faster||But setting time of concrete is normal|
|Concrete strength||High concrete strength compared to river sand.||Less concrete strength|
|Over sized particles||0%., as it is artificially manufactured.||1 – 6% of over sized particles is expected.|
|Water absorption||It has more water absorption (2 % – 4 %)||It has less water absorption (1.5 % – 3 %)|
|Workability and slump||Concrete workability and slump is low when compared to that of river sand.||Concrete workability and slump is more when used with river sand.|
|Environment-friendly||Natural coarse aggregates is used in m- sand to form, less damage is caused to the environment.||Harmful to the environment by eco imbalances, reduction of groundwater level.|
|Adulteration||Less adulteration||High adulteration since filtered sand is mixed together.|
|Usage||Recommended for block/brick works and mainly rcc purposes.||Recommended for block/brick works and mainly plastering works.|
|Quality control||Better quality control since manufactured in a controlled environment.||No control over quality as it is naturally occurring.|
|Bulk density||1.7 kg/cm^3||1.4kg/cm^3|
|Specific gravity||2.5 -2.9 – depending on parent rock||2.4-2.7 -depending on catchment area|
|Cost at coimbatore||M sand cost varies between 40 to 50 rs/cft depending on transportation distance .||River sand cost varies between 140 to 150 rs /cft .|