Approval of M-sand delays construction

The ongoing double-decker bridge whose work was stalled due to differences over the usage of M-sand between State government and PWD

CHENNAI, Nov. 17: The double-decker bridge coming up at the Velachery-Vijaynagar junction has been delayed due to differences over the use of artificial sand instead of river sand that is usually used for constructions.

The work resumed in December 2016 after the Public Works Department (PWD) approved the use of artificial sand, also called M-sand, short for manufactured sand. The Madras High Court had approved its use in 2012.

M-sand has several benefits in comparison to natural river sand. It is cheaper, has nil water content, gives more strength to the cement and can be mixed with fly ash to make bricks.

According to  an amendment in the Tamil Nadu Minor Mineral Concession Rules, 2015, the right to exploit sand rested with the State Government. 

The recommending committee, appointed by the Madras High Court, directed the PWD to carry out research to find an alternative to natural sand. It had also stayed the sand quarrying operations in the Cauvery river between Karur (Mayanur) and Tiruchy.

However a senior official from the Department of Geology and Mining said the PWD continued to insist on the use of river sand saying it was better in quality compared to M-sand.

There were allegations that the PWD wanted contractors to get its permission to use M-sand and that the contractors had to pay bribes if they wanted to use the artificial sand. As a result no contractor approached the PWD for permission to use M-sand.

However the supply of river sand dried up with the High Court banning sand mining operations on river beds for environmental reasons, the official added.

“After mining 1-2 metres of sand, the groundwater table is exposed.  This causes the ground water to evaporate leading to water depletion in surrounding areas which affects agriculture,” said the official from the department of Geology and Mining.

  • Artificial sand or M-sand is manufactured after crushing Charnockite which is found in Tamil Nadu.
  • M-sand has several benefits in comparison to natural river sand. It is cheaper, has nil water content, gives more strength to the cement and can be mixed with fly ash to make bricks.
  • It binds better with  mortar or cement and retains more water than riverbed sand. Thus it strengthens the overall cement. It increases the ability of building material to withstand pressure without bending.

Then on July 12, 2017 the PWD issued a circular for using M-sand in government projects as an alternative to natural sand, if the officials encountered shortage of river sand, The circular lays down norms for quality checks before using it for government projects.

The Assessment Committee of the PWD has representatives from several institutions such as Anna University, Indian Institute of Technology, Bureau of Indian Standards (BIS),  Structural  Engineering Research Centre and other government bodies. It examines the products based on the licence from BIS or test reports from Central Government laboratories or BIS approved laboratories.

The artificial sand comes from quarries that are licensed by the State Government after getting environmental clearance from district and state environment impact assessment authorities.

These officials are required to inspect the area and clear papers everyday. However, they visit offices once in a month and clearances are granted like a “third class Railway ticket”, said the senior official source.

Artificial sand or M-sand is manufactured after crushing Charnockite which is found in Tamil Nadu.

In the districts that do not have quarries or are not suitable for quarrying they get the stones from Andhra Pradesh and Karnataka. Tamil Nadu is a flood plain and does not have many quarries in comparison to Karnataka which is a plateau.

M-sand has several benefits in comparison to natural river sand. It is cheaper, has nil water content, gives more strength to the cement and can be mixed with fly ash to make bricks.

It binds better with  mortar or cement and retains more water than riverbed sand. Thus it strengthens the overall cement. It increases the ability of building material to withstand pressure without bending.

Sand is a depleting natural resource and takes millions of years to form after wind, water and the Sun have weathered rocks over years. With rampant construction activities in cities, there will be no natural sand left soon.

 

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