Posted on 04/26/2014 9:53:08 AM PDT by TurboZamboni
new water-repellant concrete impregnated with tiny superstrong fibers promises to leave roads and bridges free of major cracks for up to 120 years.
University of Wisconsin-Milwaukee civil engineers have developed a concrete mix that is durable and superhydrophobic. They call it Superhydrophobic Engineered Cementitious Composite (SECC). Preventing normally porous concrete from absorbing water means that liquid can’t get inside, freeze and cause it to crack. The concrete’s unusual characteristics, including being significantly more ductile than traditional concrete, means that cracks that do form do not propagate and cause failure.
“Our architecture allows the material to withstand four times the compression with 200 times the ductility of traditional concrete,” said associate professor Konstantin Sobolev, whose lab created SECC.
(Excerpt) Read more at txchnologist.com ...
I had a concrete driveway once that started crumbling after the first winter. It had a warranty but the warranty company went bankrupt.
why bother making roads that outlast an election term?
i wouldn’t thinmk that b/c short fibers are added, that they’d not use rebar. rebar is needed for structural stablility, regardless. plus with water repellant concrete it will not rust and fail for a very, very long time, if ever.
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There are archeologists studying Roman concrete from 2000 years ago. Their concrete has lasted millennia, while ours rarely lasts decades. One group thinks they figured out how the Romans made concrete for marine projects, whereas ours can’t cure in salt water.
If the concrete doesn’t absorb ANY water though, it will leave a thin sheen of water on the surface of the roads, leading to extensive hydroplaning.
They will have to come up with a surface treatment that can solve that problem, I’m guessing.
But the bad news is that this concrete will likely increase global warming.
What happens when someone discovers that the “tiny super strong fibers” cause lung cancer when they get into the atmosphere?
The Secrets of Ancient Roman Concrete
http://www.history.com/news/the-secrets-of-ancient-roman-concrete
There’s no doubt that the ancient Romans were master builders. Many temples, roads and aqueducts constructed during Roman times have held up remarkably well, despite the wear-and-tear—in the form of military invasions, tourist mobs and natural disasters such as earthquakes—they’ve had to endure. In particular, geologists and engineers have long been fascinated by Roman harbors, many of which stand almost intact after 2,000 years or more, despite constant pounding by seawater. Now, a team of researchers from Italy and the United States has analyzed a sample of concrete taken from a breakwater in Italy’s Pozzuoli Bay, at the northern tip of the Bay of Naples, which dates back to 37 B.C. Their findings, reported earlier this month in the Journal of the American Ceramic Society and American Mineralogist, may revolutionize modern architecture.
By analyzing the mineral components of the cement taken from the Pozzuoli Bay breakwater at the laboratory of U.C. Berkeley, as well as facilities in Saudi Arabia and Germany, the international team of researchers was able to discover the “secret” to Roman cement’s durability. They found that the Romans made concrete by mixing lime and volcanic rock to form a mortar. To build underwater structures, this mortar and volcanic tuff were packed into wooden forms. The seawater then triggered a chemical reaction, through which water molecules hydrated the lime and reacted with the ash to cement everything together. The resulting calcium-aluminum-silicate-hydrate (C-A-S-H) bond is exceptionally strong.
By comparison, Portland cement (the most common modern concrete blend) lacks the lime-volcanic ash combination, and doesn’t bind well compared with Roman concrete. Portland cement, in use for almost two centuries, tends to wear particularly quickly in seawater, with a service life of less than 50 years. In addition, the production of Portland cement produces a sizable amount of carbon dioxide, one of the most damaging of the so-called greenhouse gases. According to Paulo Monteiro, a professor of civil and environmental engineering at the University of California, Berkeley, and the lead researcher of the team analyzing the Roman concrete, manufacturing the 19 billion tons of Portland cement we use every year “accounts for 7 percent of the carbon dioxide that industry puts into the air.”
(more at link.)
I want a boat made out of it.
Studded snow tires kill the roads here in the Northwest - I had a BMW when I moved out here and I could go hands free down the interstate for miles the grooves were so deep. When we get hard rains (rare) the hydroplane action is ridiculous.
With the improvements in siped softer rubber winter tires I am dumbfounded that they still allow the studded tires considering the damage to the roads.
“The joke going around here is the cops were told to ignore cars veering around on the road. The drunks are driving the cars going straight, oblivious to the strip mines they are running over.”
The same joke is out here in Californicator land.
A younger relative was dodging the pothole in his Californicator county, and he was stopped by a local cop.
The cop said that he was weaving all over the road, and the cop wanted to run a road side sobriety test on him.
He told the cop, that was fine, but he should run one on the cop for not dodging the potholes.
The cop actually grinned and told him to have a nice day and drove off.
BINGO!
In Minnestoa, if we aren’t spending money rebuilding the roads we already have, we will spend it making more bike paths and light rail stations to display government grant artists ‘art’.
This from Milwaukee.
Ironically, I spent a few months in Milwaukee in 2011, and they’ve got a lot of cement streets.
Some of them, though, are nearly impassable. Not because the concrete has failed, but because the roadbed was improperly prepared, and the vertical alignment on all the slabs is now gone.
There was one street in particular I once drove on, and never again because it literally made me seasick.
From the replies at the link:
This is a great thing, although I believe Wisconsin did a test back in the sixties, they poured a stretch of I-94 for about 20 miles, same concrete, steel & thickness as the rest of the freeways ,but with a different expansion joint cut into the roadway.
They cut diagonal expansion joints, about 45 deg. angels instead of 90 deg. angles as is used on other roadways. By doing this the load was carried more evenly across the roadway. this roadway stayed smooth & crack-less for 20 yrs. ! Not one pothole !The 20 year test was a total success !
After 20 years,the state tore this roadway up & replaced it with a conventional roadway, with the expansion joints cut at 90 deg. angels, and with-in a year, the new highway was full of pot-holes & cracks!
I see the jobs of construction workers that they say would be lost ,but if you think about how long it would take to replace the roadways across all of North America, I can see generations of workers at work ! Plus after generations they would adapt towards other occupations as well !!
Excellent guess...
Longitudinal grooving works well, but on I-84 east of Boise they did transverse grooves. That'll drive you crazy!
Mary Poppins sure can carry a tune.
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