Greenwood: Concrete roads may fix themselves
Concrete, heal thyself.
We can thank the Romans for concrete, the world’s most common and durable building material, but for all of its reliability concrete has one major problem: It cracks.
Concrete cracks for a number of reasons, but the most common are from the weather and the stress from the loads it carries. But believe it or not, we are on the cusp of concrete that heals itself.
Over in Holland, a microbiologist by the name of Henk Jonkers at Delft University of Technology has developed a concrete that contains built in bacteria that fills in cracks after they form.
The bacteria is enclosed by miniscule pellets that resemble a fine white powder that is mixed into wet concrete prior to pouring.
The pellets contain dormant Bacillus and/or Sporosarcina bacteria plus their food source, which is calcium lactate (a form of baking powder).
When a crack forms and water seeps in, the pellets turn into a healing version of Pop Rocks in which the bacteria breaks out of its shell and starts scarfing down that yummy calcium lactate.
The bacteria then excretes limestone that then fills in the cracks, which then prevents more water from seeping into the concrete.
Cool alert: The bacteria can live in its dormant state for up to 200 years without food until it gets wet, then it returns to life like limestone-loving Sea Monkeys.
To borrow from an old Thunderbird wine commercials, “what’s the price? Not very nice.”
The cost of the bacteria-packed concrete is about twice that of normal concrete due to the cost of calcium lactate. But Jonkers is convinced the cost will drop once they get the bacteria to use a sugar-based food source instead.
Is there any similar research here in the U.S.?
At the University of Michigan, civil engineering professor Victor Li has come up with a self-healing concrete with the Roman emperor-esque name of Cementitious.
The substance consists of regular concrete that is mixed with microfibers that helps concrete to bend in stead of crack. If it does crack, the cracks are usually less than 50 microns wide, which is thinner than a human hair.
The cracks expose the composite to water, which it absorbs and then it too begins to “grow” new concrete to fill in the miniscule cracks.
Once again the problem is money. Once the costs are dropped, Li is sure the new concrete will be commonplace in the not too distant future.
I-69: In Lapeer, the freeway has one lane open in each direction from M-19 to Taylor Road.
I-69 Business Loop: In Port Huron, the WB lanes are closed from 32nd Street to I-94.
I-69: In Lapeer, the freeway has EB single lane closures from Range to Lapeer roads.
I-94: In Detroit, the EB ramp to NB I-75 is closed for bridge repairs.
M-8 (Davison Freeway): In Detroit, the EB ramp to SB I-75 is closed and Oakland Avenue over the Davison is closed.
M-10 (Lodge Freeway): In Detroit, the road will have one lane open on the SB service drives near Meyers and McNichols roads.
M-53 (Van Dyke): In Sterling Heights, the road has one lane open in each direction from 14 Mile to 18 Mile.
M-85 (Fort): The road is closed across the Rouge River on the Detroit/Dearborn border.
M-85: In Detroit, the road has three lanes closed between Clark Avenue and Rosa Parks Boulevard.
12 Mile: In Madison Heights, the ramp from WB 12 Mile to SB I-75 is closed for repairs.