经济学人下载:治愈混凝土癌症(1)

Modern civilisation is built on concrete and steel. Put the two together, though, and you can generate a problem.
现代文明是建立在钢筋混凝土基础上的。然而，将两者结合起来，就会产生一个问题。

Reinforcing concrete with steel rods called rebars is the basis of modern construction.
钢筋混凝土是现代建筑的基础。

But because water gets in through tiny cracks, the rebars rust. This causes them to expand, widening the cracks and weakening the concrete.
但是因为水会从细小的裂缝里渗透进来，所以钢筋会生锈了。这会导致裂缝扩大，混凝土变软。

Hence such structures require constant attention and often have design lives of only 60-100 years.
因此这样的结构需要持续的关注，并且其设计寿命仅有60到100年。

That is pitiful compared with, say, the concrete dome of the Pantheon in Rome—which was completed in 125ad and still stands.
这与罗马万神殿的圆顶相比，简直是小巫见大巫，罗马万神殿建成于公元125年，至今仍屹立不倒。

Various ways of delaying or preventing concrete cancer, as this corrosion is known colloquially, have been tried.
人们已经尝试了各种延迟或预防混凝土癌症（腐蚀的通俗说法）的方法。

These include recipes for concrete that is less permeable to water,
其中包括不透水混凝土的配方，

and rebars made from rust-resistant materials such as stainless steel or composites.
以及由不锈钢或复合材料等防锈材料制成的钢筋。

Such approaches work, but they can be expensive. This may be about to change.
这种方法确实有效，但成本可能很高。这种情况可能即将改变。

Next year, if all goes well, a pair of footbridges intended to be cancer-proof will open in Geelong, a town 75km south-west of Melbourne, Australia.
明年，如果一切顺利，澳大利亚墨尔本西南75公里处的吉朗镇将建成两座防癌人行桥。

These bridges, which will act as prototypes for more than 150 others planned for the expanding city,
这些桥梁将用作其他150多个城市扩张计划的原型，

will be constructed using a novel approach that combines glass-fibre and carbon-fibre rebars.
且将使用一种结合玻璃纤维和碳纤维钢筋的新方法来建造。

They will, though, cost about the same as equivalent conventional bridges.
不过，它们的造价将与同等的传统桥梁差不多。

The new design is the brainchild of a joint team of researchers from Deakin, a local university, and Austeng, the firm contracted to build the bridges.
新设计将由来自当地迪肯大学和桥梁承建公司Austeng的联合研究团队共同完成。

This team began with commercially available rebars made from carbon-fibre composite.
这个团队开始使用由碳纤维复合材料制成的商业钢筋。

Although these are as strong as steel ones, they are expensive.
虽然它们和钢的一样坚固，但是它们很贵。

They are, therefore, most often used in specialist structures such as buildings to house MRI hospital scanners,
因此，它们最常被用在一些特殊的建筑物上，比如用来放置核磁共振医院扫描仪的建筑物，

where electromagnetic interference from metal can cause problems.
在那里来自金属的电磁干扰可能会造成问题。