Sand is an important ingredient in concrete and is also widely used in the making of glass, electronics and even in shale gas fracking. Its estimated that sand is the most-consumed natural resource on the planet besides water. It is roughly estimated that the total sand consumption in India is around 700 million tonnes, the number which is likely to go up sharply in the coming years thanks to rapid pace of urbanisation taking place in the country. China alone has likely used more sand this decade than the United States did in the entire 20th Century.
Sand traditionally has been a local product. However, things are changing and regional shortages and sand mining bans in some countries are turning it into a globalized commodity. Its international trade value has skyrocketed, increasing almost six-fold in the last 25 years. When India was facing acute shortage of sand in the recent past some states had started importing the material from East Asian countries like Malaysia. Similarly, there is so much demand for certain types of construction sand that Dubai, which sits on the edge of an enormous desert, imports sand from Australia.
No consumption data available
In spite of the fact that sand is one of the most extracted in India (and in whole world also) there is hardly any data about the sand consumption in the country. So, one has to estimate sand consumption in construction purely based on cement production. India annually consumes about 330-340 million tonnes of cement and against that (as per civil engineering manual) you need about 550 million tonnes of sand. In other words, construction sector consumes more than 550 million tonnes of sand (through concrete) every year. Sand is also used (in construction) in tiles laying and foundations. It also has several industrial uses. In the coming years, scale of construction is going to go up with further push to urbanisation and infrastructure development which in turn will increase the demand for sand. Since we are already facing sand scarcity, the situation is likely to turn from bad to worse in the coming years.
One of the ways out is to recycle the building debris to produce sand. Though the recycled sand has the same strength as the original one, there is little hesitancy on the part of developers to use the recycled material due to wrong perception about its quality and strength. So, there is need to increase awareness among the builders about the recycled and its qualities.
Sand mining becoming environment hazard
Extraction of sand has become reckless and often illegal. In India, sand mining has gone to the hands of mafia which in turn has become security and social issue. There are instances of mafia (engaged in sand mining) diverting rivers, destroying aquaculture habitats, and devastating lakes and wetlands. Elsewhere too situation is no better with sand miners causing irreparable damage to environment. Singapore, the world’s largest sand importer, launched a vast fleet of ships to dredge and vacuum up millions of tonnes of sand from seabeds annually, destroying ocean habitat and obliterating over 20 entire islands. In Cambodia, the dredging threatens mangrove forests, seagrass beds, rivers, estuaries, and the ocean floor. Vietnam, which has outlawed sand exports to Singapore, continues to lose forest and farm land to supply its own domestic demand. Further, in Africa, China, and Southeast Asia, the extraction of sand from rivers and lakes creates standing pools of water that have become breeding sites for malaria-carrying mosquitoes.
M-sand not preferred
M-Sand (Manufactured sand) is often considered as substitute of river sand for concrete construction. Manufactured sand is 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. However, there has been general reluctance to use the M-Sand in construction works mainly due to lack of supply of good quality M-Sand. It is also observed that quarry dust which contains flaky particles and higher percentage of micro fines (particles less than 75 micron) is being supplied in the name of M-Sand and these properties affect the quality of concrete and other works.
Increased mining of coastal sand
Another problem arising out of shortage of sand is the resultant increased mining of marine and coastal sand. For concrete, in-stream sand requires less processing and produces high-quality material, while marine sand needs to be thoroughly washed to remove salt. If the sodium is not removed from marine aggregate, a structure built with it might collapse after few decades due to corrosion of its metal structures. Some desert sand can be used if mixed with other material.
Demand will increase further as urban areas continue to expand and sea levels rise. Major international agreements such as the 2030 Agenda for Sustainable Development and the Convention on Biological Diversity promote responsible allocation of natural resources, but there are no international conventions to regulate sand extraction, use and trade. This lacuna needs to be corrected.
Training of architects and engineers, new laws and regulations, and positive incentives are needed to initiate a shift for lowering our dependency on sand. Renewable and recycled materials need to be targeted for building houses and roads. The government should also pay attention to introduce scientific mining operations, followed by ecological restoration.