As all know river sand is used in the construction industry as a fine aggregate which is a material that is finer than gravel and coarser than silt. This is one of the main ingredients used in the construction industry when it comes to concrete, cement plaster mix, not in only Sri Lanka but all over the globe. The sand is not only used in constructing material but it’s also used in landfilling, reducing groundwater level by using it in sand piling and many other works in the construction industry. Sri Lanka has a needy of river sand only for the use of the construction industry, approximately around 7 to 7.5 million cubic meters per year, and has been a profitable business around the country in a legal and illegal manner.
The reason why the river sand is that important is that it has some special characteristics, because of subjected to years of abrasion, the shape has been more rounded and smooth, and for years of washing the sand has very low silt and clay contents. It helps to improve the workability of the concrete and mortar and because of the lower silt and clay contents, the river sand improves the quality of and concrete and cement mortar because the presence of silt or clay would harmfully affect the workability and the strength of the concrete or mortar mix. With the growth of construction industry material requirement has been in demand the availability of materials is getting less from day by day and the construction cost rise on an almost daily basis. As per all the other years, Sri Lanka has a construction growth for the year 2019 as well and as per the Sunday observer article published on 2019 August 18th say that the country construction industry has contributed 7.1 percent for the country’s GDP in the year 2019 which has a healthy growth. Sri Lanka needs more materials for fulfilling the requirement of the industry but not the little beautiful island but all the other countries.
Issues of river sand mining
As everything has a limit river sand mining also has its limits which have already exceeded in many areas. This limitless sand mining has brought many issues in the environment.
- Sand mining makes areas more prone to flooding
- Sand mining adversely affects tourism
- Sea Water coming into the country
- It affects the stability of river Structures
Are some of the effects that happen because of inappropriate or illegal sand mining
Sand Mining Makes Areas More Prone to Flooding
Usual thought that everyone will be having as a sand mining make the river deeper hence the flood effect will be removed from the area so thinks that it’s a healthy move. But this is a reason for areas to be flooded. It destroys the river banks and the barriers are removed hence the area has a greater opportunity of being a flood.
Sand Mining Adversely Affects Tourism
Many tourists come to countries like Sri Lanka to enjoy and to love nature. Sand mining destroys the aesthetic beauty of the river banks, and also makes the ecological system in these areas unstable. If such riverside areas are popular tourist destinations, then the tourism potential of such areas will be lost. The view of the area will be unaesthetic and will not be looking good.
Sea Water coming into the country
Seawater mixing up with River water is one of the major issues that the environment faces. Sand mining will make the river more dipper and when the limit exceed which is the river bed goes below the sea bed level the usual routine stops and then the sea waters start to come into the country. These effects are not only to the animals that live underwater this is affecting humans as well.
It affects the stability of river Structures
By doing the sand mining in an area the total area gets affected. Because of the water flow the sand on the undisturbed area stars to fill up the excavated area and for this reason, most nearby areas for the excavated area also get affected.
Many direct and indirect issues happen due to sand mining. Important on the sand to the construction industry the same amount of importance should be provided to the issues or impact which is happening. To solve the construction needs and at the same time to save the river and the river bed and also the living of the people animals around. So the people who are involved in the construction industry were keen to find out a new solution or a new material that can be used as an alternative for sand and as a better option for the construction industry. And also people had an idea of replacing river sand with industrial waste as an alternative. That alternative should be easy to find, cost-effective material and also a material which will not bring any additional negative impact on the concrete or in the cement mix.
- Copper Slag
- Granulated Blast Furnace Slag
- Washed Bottom Ash
- Quarry Dust
- Foundry sand
- Construction and Demolition waste
- Spent Fire Bricks (SFB)
- Sheet Glass Powder
- Fly Ash
- Manufactured sand
Manufacture sand is one of the main famous replacement materials used in the construction industry to replace the river sand. With the demand of the river sand, the cost raised, and accordingly, the environmental impact also became more in negative growth. With the above-mentioned alternatives and many other alternatives were used in the construction industry and those alternatives either should be better than the river sand or should be at least manageable.
Manufactured sand is made out of hard granite stone by crushing them. The crushed sand is of cubical shape with grounded edges, washed and graded to as a fine aggregate in the construction. The size of manufactured sand is less than 4.75 mm. This alternative this famous because of its availability and the cost of transportation is in the lower part because of the availability. This manufactured 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. Another advantage of using manufactured sand as an alternative for the river sand is because it can be dust free and also the sizes of manufactured sand can be controlled easily so that it meets the required grading for the given construction.
This is an economical solution and more ecofriendly than river sand because prevents dredging of river beds to get river sand which may lead to environmental disaster like groundwater depletion, water scarcity, the threat to the safety of bridges, dams, etc. hence this makes manufacture Sands more eco-friendly than river sand.
By using manufacturing sand as a replacement for the natural river sand brings up a correct balance between industry needs and a solution for environmental issues. M-sand is a high-quality material that contradiction non-refined extra from coarse aggregate productions.
|Nature||Spherical particle||Cubical particle||Good|
|Gradation||Cannot be controlled||Can be controlled||–|
|Particle more than 75 micron||Presence of silt shall be less than 3% (IS:383-1970) reaffirmed 2007||Presence of dust particle shall be not more than 15%||Limit – 3% for uncrushed & 15% for crushed sand|
|Silt and Organic impurities||Present (Retard the setting & Compressive Strength)||–||Limit of 5% for Uncrushed & 2% for Crushed sand|
|Specific gravity||2.3 – 2.7||2.5 – 2.9||May differ|
|Water absorption||1.5 – 3%||2 – 4%||Limit 2%|
|Ability to hold surface moisture||Up to 7%||Up to 10%|
|Grading zone(FM)||Zone II and III||Grading zone (FM)||Zone II and III|
|Soundness||Relatively less sound (Ex. >5)||Relatively sound|
|Alkali Silica Reactivity||0.002 -0.01||0.001- 0.008||Limit 0.1%|
All the above specification shows that the M sand which is known as manufacture sand is better or manageable as a replacement for the construction industry. But the most important factors still have not to be defied, it can be defied and describe with doing necessary testing and if the testing is positive it will make a huge impact on the construction industry.