Opinion, by Alfonso Stefanini
RIO DE JANEIRO, BRAZIL – I've heard that man's best friend in not the dog, but reinforced concrete. The material allows for the building structures that define modern urban living, from skyscrapers to hydroelectric dams. This essential inanimate compound is composed mainly of sand, gravel, cement and water.
That being said, it is fair to say sand is the second most widely used material in sheer volume in the world, losing only to water. You cannot hold a . . .