- Owing to acute shortage of sand in the state, the government has decided to formulate a M-sand policy, which is the only alternative to meet the excessive demand
- The government would aggressively promote production of manufactured sand.
- Though M-sand is being produced, it is only available in urban centers and not in rural areas. Sand has become so scarce that constructing even small houses has become difficult. Several of the PWD works have been hit. There is a huge gap between demand and supply.
- Hence, there is a need to promote M-Sand production
- A total of 98 M-sand plants are operating in the state at present and 68 more plants would be started in two-three months. Meanwhile, the government would offer 10 acres of land to existing M-sand plants to double their production.
- The price of M-sand would be 50% less compared to the price of river sand.
- Instructions have been given to use maximum M-sand in government works
- Quality testing laboratories would be strengthened to ensure the production of good quality M-sand and awareness programmes would also be organised to popularise its uses.
- Manufactured sand is a substitute of river for construction purposes sand produced from hard granite stone by crushing. The crushed sand is of cubical shape with grounded edges, washed and graded to as a construction material. The size of manufactured sand (M-Sand) is less than 4.75mm.
- Manufactured sand is an alternative for river sand. Due to fast growing construction industry, the demand for sand has increased tremendously, causing deficiency of suitable river sand in most part of the word. Due to the depletion of good quality river sand for the use of construction, the use of manufactured sand has been increased.
- Another reason for use of M-Sand is its availability and transportation cost. Since this sand can be crushed from hard granite rocks, it can be readily available at the nearby place, reducing the cost of transportation from far-off river sand bed.
- Thus, the cost of construction can be controlled by the use of manufactured sand as an alternative material for construction. The other advantage of using M-Sand is, it can be dust free, the sizes of m-sand can be controlled easily so that it meets the required grading for the given construction.
- Experts vouch that manufactured sand is not only a viable alternative to natural sand, but is superior in many ways. River sand is not graded properly and has excessive silt and organic impurities like coal, bones, shells, mica and silt and these can be detrimental to durability of steel and concrete, whereas manufactured sand has no silt or organic impurities.
- Two factors determine the quality of manufactured sand; size and shape. The sand particles should not be flaky and elongated as that may make the mix weak and affect the durability and strength of the concrete.
- Rocks with more mica content are considered not suitable for manufacturing sand.
How is it Manufactured?
- M-Sand is cubical in shape and is manufactured using technology like High Carbon steel hit rock and then ROCK ON ROCK process which is synonymous to that of natural process undergoing in river sand information.
- Manufacturing of sand involves three stages, crushing of stones into aggregates by VSI, which is fed into a rotopactor to crush aggregate into sand in required grain sizes. Screening is done to eliminate dust particles and washing of sand eliminates very fine particles present within. The end product will satisfy all the requirements of IS:383 Zone II and can be used in concrete and construction.
- Only, sand manufactured by VSI crusher and rotopactor is cubical and angular in shape. Sand made by other types of machines is found to be flaky and contain higher percentage of dust. Generally, manufactured sand is classified as Zone I, Zone II, Zone III and Zone IV (i.e. coarser to finer). There is sieve designation for each zone. Gradation is made in accord with the usage of the sand. There are testing sieves, consists of 4.75mm, 2.36mm, 1.183mm, 600microns, 300 microns and 150 microns.
- Zone I sand is used for concreting while sands Zone II to IV are used for plastering. Tests have revealed that the characteristics of mortars and concrete using M-sand as fine aggregate are superior when compared to the natural sand as fine aggregate.
Issue: It would be difficult for a layman to distinguish manufactured sand from rock sand. Rock sand is the residue dust formed during the stone crushing. Chances of developing early cracks and weakening are more as it is devoid of required grades and not undergone adequate cleaning.
Advantages of Manufactured Sand (M-Sand) are:
- It is well graded in the required proportion.
- It does not contain organic and soluble compound that affects the setting time and properties of cement, thus the required strength of concrete can be maintained.
- It does not have the presence of impurities such as clay, dust and silt coatings, increase water requirement as in the case of river sand which impair bond between cement paste and aggregate. Thus, increased quality and durability of concrete.
- M-Sand is obtained from specific hard rock (granite) using the state-of-the-art International technology, thus the required property of sand is obtained.
- Mortars with M-sand exhibit better workability and water retention characteristics, confirms a study held at IIS, Bangalore. For 1:4 cement mortar, to achieve 100 per cent flow the water cement ratio required is about 0.88 using M-sand whereas 1.20 using river sand. Lower water-cement ratio results in better characteristics of mortars in hardened state.
Did you know?
Pune-Mumbai expressway was completely built using manufactured sand. Runway of Thiruvananthapuram International airport, new flyover at Thakaraparambu and Palayam underpass at Thiruvananthapuram are also learnt to have constructed using M-sand.