The world’s resource on concrete will soon runout. Concrete is the second most consumed substance on earth after water. It’s a $37-billion industry with output of 10 billion tons per year. Concrete is a primary material in the construction industry. It is composed of sand, gravel and cement as the bonding agent. It is strong yet light. It is cheap and widely available. But its supply will not last for long. Sand in particular will get low in stock.