“活”混凝土能自愈，建筑物裂縫不再愁

They’re expensive， ugly and sometimes dangerous： cracks in concrete. From bridges to houses， the renovation of buildings in the EU cost about six billion Euros a year.

But the era of expensive renovations could soon be over. The Dutch micro-biologist， Hendrik Jonkers， has invented a type of concrete that may 2）spell the end of those annoying cracks and 3）crevasses， thus saving billions of Euros.

Hendrik： （via translator） We think our concrete will revolutionize the way we build because we’ve been inspired by nature. Plants and animals have the ability to heal themselves， and now we’ve made it possible for concrete to do the same.

The problem with conventional 4）reinforced concrete is that stress gradually creates small cracks. Water penetrates the steel in the concrete， which starts to rust and become 5）brittle. This often happens after 20 to 30 years.

At the 6）University of Delft， Jonkers discovered the special ingredient for his“magic concrete” after a long search： natural bacteria. They usually occur near volcanoes and are heat and cold 7）resistant. Jonkers mixed them into the concrete so the building materials “come alive” in the truest sense of the word.

Hendrik： （via translator） The bacteria are found in nature. They usually live in stones. The special thing about them is that they form 8）spore， therefore they’re well-suited for our concrete， because they can survive for a long time.

The bacteria are in this powder. This is a mixture of the bacteria and their food， 9）calcium lactate. The powder is mixed with water and concrete components. The organic concrete is now ready to go. This miraculous power unfolds when it’s applied. When cracks start to occur， water finds its way in. The water then awakens the bacteria. They can lie 10）dormant for 200 years in the concrete， but when they come into contact with water， they become active and eat the food. Then they 11）secrete limestone， the main component of cement. This closes the cracks in the concrete.

It takes just three weeks for the diligent bacteria to seal the cracks， no matter how long the cracks are.

Hendrik： （via translator） There’s no limit to the length of the cracks， which can be centimeters or meters， even kilometers long， but the width is crucial. Here we see a crack with a width of 0.2 millimeters， but we can heal cracks up to 0.8 millimeters wide.

This process can also work on existing buildings. Jonkers and his team are developing a special liquid that can be applied to cracks in buildings made of conventional concrete. This liquid also contains the special bacteria. It will be launched later this year. The organic concrete will follow in 2016.

This is the first building constructed using the magic concrete. The concrete layer is six centimeters thick， which is a third less than a conventional house. Jonkers inspects the cracks regularly to see that they’re healing. So far everything is working perfectly. The hidden helpers in the concrete could trigger a revolution and bring Hendrik Jonkers the 12）coveted 13）European Inventor Award.

它們代價高昂，外觀難看，而且有時還會帶來危險：它們就是混凝土中的裂縫。從橋梁到房屋，歐盟每年大約要花費六十億歐元來進行建筑物維修。

但是，這個高價維修的時代或將成為過去。荷蘭微生物學家亨德里克·揚克斯發明了一種新型混凝土，這可能意味著我們將告別那些惱人的裂縫，并因此省下幾十億歐元。

亨德里克：（通過翻譯）我們從自然中得到了啟發，相信我們的新型混凝土將帶來建筑方式上的變革。動植物可以自愈，現在我們賦予了混凝土相同的能力。

傳統鋼筋混凝土存在一個問題：它在壓力作用下會逐漸產生小裂紋。水分會滲透進去，接觸到混凝土里的鋼筋，使之生銹脆化。這種情形時常發生在有二、三十年歷史的建筑物中。

在代爾夫特理工大學，揚克斯經過漫漫探尋，終于發現了制成“魔法混凝土”的特殊原料：天然細菌。這些天然細菌通常出現在火山附近，既耐熱又抗冷。揚克斯將這些細菌與混凝土混合，建材就真的“活”起來了。

亨德里克：（通過翻譯）這些細菌自然天成，通常存在于石頭中。其特別之處在于它們可以形成孢子，能長期存活，因此非常適合我們的混凝土。

上述細菌就在這種粉末中。這是細菌及其食物乳酸鈣的混合物。把這粉末和混凝土原料加水調和，有機混凝土就大功告成了。這種材料付諸實踐后，它的神奇效力就會顯現出來。裂縫一旦出現，水就會滲進去，喚醒天然細菌。這些細菌能在混凝土中休眠二百年，不過一接觸到水分，它們就會被激活，開始進食，然后分泌石灰石——也就是水泥的主要成分，從而修復混凝土中的裂縫。……