Science

Microscopic construction workers

Ecuadorian peasants may soon get help from billions of microscopic construction workers, as TU Delft researchers plan to repair their leaking irrigation canals with limestone producing bacteria.


 


Small pieces of concrete are scattered around in the cement laboratory at the faculty of Civil Engineering and Geosciences. These are no ordinary scraps but rather bits of self-healing concrete. Inside are little globules containing bacteria that produce limestone when coming into contact with water, thereby filling cracks.


The pieces are the remnants of experiments performed by four students from secondary school RSG Pantarijn in Wageningen. The students thought it would be a good idea to repair leaking cement irrigation canals in Ecuador with the self-healing concrete. With their experiments, and the business plan ‘a concrete solution for a concrete problem’, which they subsequently wrote, they won this year’s Imagine Cup competition. The Imagine Cup is a contest organized by the TU Delft-affiliated foundation Imagine, in which secondary school students have to come up with ideas about how to exploit TU Delft inventions.


Biotechnologist Dr Henk Jonkers, who developed the self-healing concrete over the past six years, is charmed by the students’ idea. He subsequently got into contact with civil engineers at the University of Guayquil, with whom he wants to do the field experiments.


“It will be interesting to see how the self-healing concrete will perform,” says Jonkers, who – though he still needs to find financing – is confident the project will take place some time next year.


“The conditions are quite harsh in the Andes where the irrigation canal is situated. At night it’s freezing and during the day temperatures are high. The huge fluctuations in temperature also explain why the cracks appeared in the canals in the first place. We will add different types of bacteria to our cement, each flourishing at different temperatures.”


The project in Ecuador is not the only field experiment Jonkers has in mind. After years of lab work he believes the time has come for his bacteria to come out of the closet. Recently a pavilion in Breda, designed by prize winning architect Frank Marcus, was built with his self-healing concrete. And parts of the façade of the faculty building, which is due for renovation next year, will be fitted with self-healing concrete as well.

Editor Redactie

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