Sand is one of the ingredients in concrete. Sand is coarser than slit and smaller than gravel. Sand is naturally available alongside riverbanks, riverbeds, beaches, seas, and deserts. However, the demand for sand in India has increased multi-fold in the last two decades due to rapid urbanization and large-scale construction activities. The availability of sand from natural sources is inadequate to meet the huge demand. The mining of sand from natural sources is exerting pressure on the ecology and the environment. Many nations, including India, face sand scarcity.
The construction industry started adopting the usage of M-sand and P-sand, which are cheaper and better than river sand. This blog will elucidate the different types of sand and their usage in building construction.
River Sand:
Though there are several types of naturally available sand – river sand, sea sand, desert sand, and pit sand, river sand is the most sought-after sand found on riverbanks and riverbeds. These sands are naturally created when rocks are subjected to constant temperature change and attrition due to flowing water causing them to break into smaller particles. These small particles are then transported by the flowing river and are deposited in the downstream areas. The river sand is relatively yellow in color and has very little amount of salt, sulphate, or organic impurities. The river sand has inorganic impurities such as silt and clay. The river sand also has high moisture content and consumes less quantity of water when used for building construction.
However, in the last two decades, the demand for river sand has increased multi-fold thanks to the rapid urbanization of cities in India and large-scale construction activities. The river sand, which is already scarce in nature, is inadequate to meet the huge demand. Transporting river sand from the riverbeds to the far-off construction site is also a costly affair.
When builders and developers face delays in building construction due to the unavailability of river sand, they resorted to buying river sand at a higher price. They were caught unaware that they were indirectly encouraging the illegal mining of river sand that was creating an ecological and environmental impact apart from depleting groundwater levels. The Government has come down heavily on the illegal mining of river sand since then.
Sea Sand:
In some countries, sea sand, also called beach sand or marine sand, is used for building construction. Sea sand is rounded or cubical, the same as river sand. Sea sand is very fine and does not contain slit or organic impurities. It is abundantly available and can be mined at a low cost. However, it has many inorganic impurities including seashells. Sea sand contains large quantities of chloride content, which can corrode reinforcement iron and steel and reduce the load-bearing capacity of the reinforced concrete. It also contains salt content, if not removed before used for construction shall cause the plaster to crack and pop. Sea sand also has lesser compressive strength and lesser tensile strength compared to river sand.
Desert Sand:
Desert sand is much finer and smoother due to the harsh climatic conditions and extended weathering effects of the desert. As the surfaces are smooth, desert sand does not offer multidirectional linkages. The concrete slurry would slip and collapse. Therefore, desert sand is not suitable for building construction due to poor its strength.
Thus, manufactured sand (M-sand) has emerged as a sustainable eco-friendly superior alternative to river sand.
So, what is M-sand?
Manufactured sand (M-sand) is artificially manufactured sand by crushing big rocks or granites in a quarry or factory. Thus, M-sand differs from other varieties of sand in its physical and mineralogical properties.
Big hard rocks or granites are crushed in vertical shaft impactor (VSI) crushers to coarse aggregates. These coarse aggregates are then crushed in a Rotopactor to get the m-sand of the correct grain size. Finally, screening and water washing are carried out to remove tiny particles. The size of M-sand ranges from 0 to 4.75mm adhering to IS 383 zone II of the Bureau of Indian Standards (BIS).
The M-sand is cubical or angular in shape with a rough texture and is consistent in particle size. Except for water-washed M-sand, M-sand., in general, has low moisture content. It has greater durability to withstand harsh climatic variations and prevent corrosion of reinforcement steel. It has fewer inorganic impurities than the river sand, thus less wastage, and better-quality concrete. The usage of M-sand can overcome the defects occurring in concrete such as bleeding, honeycombing, segregation, voids, capillary, etc, and thus offsets construction defects. It offers better compressive and tensile strength than river sand.
M-sand can be manufactured in bulk quantities as and when needed to meet huge demand, thus consistent in its availability. It is available in different sizes for concreting, plastering, and brick or blockwork. The cost of M-sand is at least 30% to 50% cheaper than that of river sand. The transportation cost of M-sand is also much less compared to fetching river sand from the riverbeds in far-off areas.
However, there are also a few disadvantages to using inferior-quality M-sand. If the M-sand is angular, it needs more cement and water to make high-grade pumpable concrete for high-rise structures, thus an increase in the overall construction cost. Also, ungraded M-sand may contain many finer particles that can affect the strength of the structure. Due to the huge demand for sand, M-sand is adulterated with quarry mud. Therefore, quality testing of M-sand is necessary before using M-sand.
The industry started marketing very fine grades of M-sand as P-sand, plastering manufactured sand, which gives very smooth finishes to the plasters. While M-sand is used for concrete and mortar mixes while p-sand is used for plastering walls and tiling purposes. The size of P-sand size ranges from 0 to 2.36mm adhering to IS 1542 of the BIS.
With BIS standards and Government policy formulations, artificial sand is gaining prominence and usage in building construction. Karnataka is the leader in manufacturing artificial sand followed by Telangana, Tamil Nadu, Andhra Pradesh, and Gujarat.
However, homebuyers are hesitant to use M-sand and P-sand and still prefer using river sand due to limited awareness and push from the Government. As always, some manufacturers adulterate M-sand and P-sand with quarry sand and silt to meet the huge demand. The lack of quality standards was also hampering the adoption of M-sand and P-sand.
Having read this blog, you, as a homebuyer, can confidently chose properties that use M-sand choose-sand for building construction and actively contribute to preventing an ecological and environmental disaster.