A U.S.-based scientist from Chittur near here, Narayanan Neithalath, has developed ‘green building blocks,’ in which cement in concrete blocks is replaced with recycled industrial glass powder.
The new concrete blocks “are more economical, energy-efficient and environment friendly than traditional ones,” says Prof. Narayanan, an expert on cement-based materials and sustainable concretes, of Clarkson’s Centre for Advanced Material Processing (CAMP), U.S.
“They are also stronger and more durable. All these improvements occur because 20 per cent of the primary and most expensive ingredient in concrete, Portland cement, is replaced with glass powder,” he said.
A solution
“What sparked development of these green blocks was a challenge faced by Potters Industries, a major international manufacturer of engineered beads made from recycled glass. Its local plant was generating 8,000 tonnes of excess fine powder a year while making tiny pieces of high-tech applications that range from reflective highway lane paint to hypodermic needles. Potters sought an efficient use of this byproduct, which looks and feels like grayish-white baby powder,” he said.
These green blocks were used to build the 56,000-sq.ft. students’ centre of Clarkson University, scheduled to open in August this year.
Prof. Narayanan began the project’s research in 2006. It concluded in December 2008 after extensive field tests at Woodruff Block, a manufacturer in Potsdam. The company produced 75,000 blocks for the University students’ centre using this innovative formulation, he said.
Pollutant concrete
It is estimated that concrete is the world’s most widely used man-made material. Some 12 billion tonnes are used each year (a cubic meter for every person on the planet) for roads, bridges and buildings.
About 25 per cent of it is Portland cement, a limestone-based binder whose production significantly depletes natural resources and stresses the environment.
The costly, energy-intensive manufacture of cement is a major source of carbon dioxide emission.
Thus replacing it with powdered glass limits pollution, reduces energy consumption, preserves resources and saves money by utilising a far less costly leftover industrial byproduct, Prof. Narayanan said.
Glass powder is effective in concrete primarily because it is loaded with silica, which can react with other cement components (calcium hydroxide, for example) to increase the material’s strength through hydration (which leads to hardening), he said.
