CAN BAMBOO REPLACE STEEL?
Cities around the world keep growing, and every new apartment block, school and bridge needs huge amounts of concrete and steel. Yet producing these materials comes at a high price for the climate. Cement, the gray powder that holds concrete together, is made by heating crushed stone in enormous ovens. This process causes around eight percent of all the carbon dioxide released by human activity. As a result, engineers are searching for cleaner ways to build, and some of them believe the answer is a plant.(lines 1–6)
In Europe and North America, most people know bamboo only from garden shops, where it is sold as a decorative plant, or from restaurants, where it is used for cheap chopsticks. In much of Asia, though, it has been a building material for thousands of years. Even today, workers in Hong Kong tie long bamboo poles together with plastic strips to create tall frames, which they stand on while building skyscrapers. Bamboo is a kind of grass, and some species can grow almost a meter in a day. A stem is ready to harvest after three to five years.(lines 7–12)
What excites engineers most is the strength of bamboo. When it is pulled, a bamboo stem can hold as much weight as some types of steel, yet it is far lighter. Several new companies in Asia and South America now glue thin strips of bamboo into thick boards and beams that look like wood. Their products are sold in more than thirty countries, and one company reports that its orders doubled last year.(lines 13–17)
Dr. Lena Ortiz, an engineer who has tested bamboo for over a decade, admits that it must be treated to protect it from insects and rain. Even so, she is hopeful. "People forget that bamboo grows incredibly fast," she says. "A field that is cut is green again within a few years. While it grows, it also takes carbon dioxide out of the air instead of adding it, as a cement oven does. And it is happy on steep hillsides where farmers cannot plant food crops. With the right care, it could become the steel of the future."(lines 18–23)