Manufactured sand - the solution

by Gamini Warushamana

A long lasting solution for the sand issue in the construction industry is now being introduced in Sri Lanka by Triumphal Trading and Consultancy Services (TTCS).

Managing Director of TTCS Altaf Halil said that manufactured sand is the only practical solution and the technology, economic and commercial viability and lower environmental impact has been proven all over the world over 30 years ago. TTCS provides sand manufacturing plants and consultancy services.

The booming construction industry in Sri Lanka has faced a severe crisis due to lack of sand. Over-extraction of sand from rivers has caused severe environmental hazards and the extraction of sand has been restricted by regulations. Sand miners have moved to sand dunes causing another environmental hazard and this too is limited.

The result is extremely higher price of sand that is not affordable to the industry. The alternative proposed by the authorities is dredging offshore sand.

This too causes serious environmental issues such as contaminated river water in washing sea sand, contamination of soil and other maritime issues. Offshore sand will not be a solution that the construction industry faces today. It will be a short-term solution for coastal areas but for other areas the transportation cost is higher.

Halil said that most countries faced similar issues and the manufactured sand was the solution for the issue all over the world. India faced this situation ten years ago. Most of our rocks contain a higher percentage of silica, which is necessary for sand. Over 90% of the underlying area of Sri Lanka are crystalline metamorphic rocks.

Therefore, the feasibility of manufactured sand is extremely high. It is also commercially viable because manufacturing plants can be installed in every part of the country and it would slash transportation costs.

Manufactured sand is not a mere alternative for natural sand. It is a superior product that meets the exact need of the industry and enhances the quality of the construction industry. TTCS introduced Barmac sand producing plants from New Zealand, services and the consultancy services for the quarry industry.

Halil said that the cost of production of Barmac manufactured sand is lower and will slash the extremely high sand prices in the market. With the Barmac plant the cost of production of a cube (100 cubic feet) is between Rs.1,500-2,000.

The Barmac crusher can also produce sand on required gradation and this is very important to improve the quality of the construction sector. For instance, manufactured sand was used to construct the Mumbai-Pune expressway in India.

To ensure the aggregate quality it was specified that the combined flakiness and elongation index should be less than 25%. By introducing this specification less cement is required to obtain the same strength properties and much more workable concrete.

Barmac uses the rock-on-rock crushing action which is very similar to the formation of natural sand and manufactures cubical shaped sand. Manufactured sand has a rough surface while river sand has a polished surface.

When the surface of the sand is rough the bonds in any construction work are stronger and therefore manufactured sand is superior to natural sand. The shape and good gradation makes stronger concrete. It also has better viscosity and therefore better workability. Grain shape and gradation in manufactured sand reduces the volume of cement and water required. Manufactured sand has been used in the construction of the Three Gorges Dam in China, the largest civil construction in the world.

Halil said that the quarry industry in Sri Lanka needs new technology and a professional touch to facilitate the development drive in the country, specially the construction industry. There are 2,500 registered and around 500 unregistered quarries in the country but all are at a primitive stage. The development of the quarry industry will generate employment for thousands including geologists, civil and mechanical engineers and other professionals. Earlier rocks were considered a burden but today they have become a very valuable asset with new technology and new opportunities, he said.

Barmac has introduced a range of manufacturing plants - small, medium and large scale. The output varies from 3-23 Tonne/hr to 550-2080 Tonne/hr and the largest Barman plant can produce a minimum 130 Cubes (13,000 cubic feet) per hour.

The first Barmac sand manufacturing plant will be installed at a government owned quarry shortly. Manufacturing plants are expensive but the business is highly profitable, Halil said. He said the technology will be popular within a few years. In the last budget the government granted tax and duty concessions to import equipment for the quarry industry.