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[kernals12]

Prof. Rahbar, inventor of the self-healing concrete, told me in an e-mail that the demonstration at the air force base in Florida went well and that the company he co-founded to commercialize it, Enzymatic, will be doing further durability tests to make it more marketable.

[kernals12]

Study finds graphene is not harmful

https://phys.org/news/2022-06-graphene.html

[kalvado]

Study finds graphene is not harmful

https://phys.org/news/2022-06-graphene.html

1. It is graphene oxide, not graphene.
2. "PA6-rGO induced a modest and transient pulmonary inflammation." isn't exactly "not harmful"

[kernals12]

Iowa State University is testing a sprayable form of Ultra High Performance Concrete in collaboration with the Iowa and California Departments of Transportation. Professor Sri Sritharan says it will cut bridge construction times from months to days by allowing larger, lightweight pieces to be assembled on-site.

[kalvado]

Iowa State University is testing a sprayable form of Ultra High Performance Concrete in collaboration with the Iowa and California Departments of Transportation. Professor Sri Sritharan says it will cut bridge construction times from months to days by allowing larger, lightweight pieces to be assembled on-site.

Anything new compared to their 15 year old documents?
https://rosap.ntl.bts.gov/view/dot/39528/dot_39528_DS1.pdf

[kernals12]

In my latest communication with Professor Rahbar, the inventer of self healing concrete, he says they're now finishing tests to get it certified for use in New York and California and that they should be finished by the end of the semester.

[kernals12]

Graphene enhanced asphalt, developed by the Italian company Directa Plus, is being tested in England. Previous tests have found it doubles asphalt lifespan.

[kernals12]

The company Directa Plus has been given a contract to resurface 150 miles of the A4 Autostrada between Turin and Milan using graphene enhanced asphalt.
https://www.graphene-info.com/directa-plus-supply-graphene-250-km-italian-motorway-road-surfacing-project

[kalvado]

The company Directa Plus has been given a contract to resurface 150 miles of the A4 Autostrada between Turin and Milan using graphene enhanced asphalt.
https://www.graphene-info.com/directa-plus-supply-graphene-250-km-italian-motorway-road-surfacing-project

OK, now reality check.
DP is not awarded contract to resurface, but will "supply several tons of material in 2023/2024"
paving 200 km x 15m wide x 2 cm deep road would use 138 000 metric tons of asphalt, give or take. Minimal published graphene oxide content I see in  published  papers is 0.1%, with 1% being more common - for at least 138 tons, and ideally several thousand tons required for the project.

So correct reading would be "a small piece of the project would use additive supplied by DP for direct comparison of asphalt with additive  against traditional technique"



Company's 2021 revenue is €9.45M. Given that 150 miles of highway would be in $100M's, 

[kernals12]

The Dutch will be deploying a remote controlled movable barrier during construction on the A2. The purpose in this application is to provide better protection for workers, but it seems inevitable this will replace those giant trucks now used to switch over reversible lanes.

[kalvado]

The Dutch will be deploying a remote controlled movable barrier during construction on the A2. The purpose in this application is to provide better protection for workers, but it seems inevitable this will replace those giant trucks now used to switch over reversible lanes.

Would be nice to add some pricing information...

[kernals12]

Do you guys think it will ever be possible to build giant machines that can spit out a road in one fell-swoop? I think it's fair to say that such an invention would do more than any other to bring the third world out of poverty.

[Max Rockatansky]

No

[kernals12]

No

Is that because of the need to level the surface to build a road?

[kkt]

In the illustration the road building machine is accompanied by its own squadron of helicopters, apparently feeding materials to the building machine.  Helicopters are extremely expensive to operate.  Figure four hours of maintenance per hour of operation.  Why would you use helicopters when you're constructing a perfectly good roadbed behind the machine that materials could come from?

Road building has many steps.  Survey, pick route, level the route surface, install drainage, dig down and lay gravel, then concrete base probably with reinforcing metal bars, then the road surface, then markings, then signs and lights.  I have trouble picturing one machine doing all those steps, especially since some steps require drying time in between them.

[skluth]

That idea was used in Kim Stanley Robinson's Mars trilogy. In the books, roads are built with machines that take in sand and other regolith in the front and extrude a perfectly good road in the rear. IIRC, the machines all run on solar power but run independently, needing no human operator. Of course, it's a lot easier when dealing with a virgin landscape like Mars than trying to build a road anywhere on our planet.

[kalvado]

That idea was used in Kim Stanley Robinson's Mars trilogy. In the books, roads are built with machines that take in sand and other regolith in the front and extrude a perfectly good road in the rear. IIRC, the machines all run on solar power but run independently, needing no human operator. Of course, it's a lot easier when dealing with a virgin landscape like Mars than trying to build a road anywhere on our planet.

Things would be significantly easier if there are no precipitation to worry about. Organics in the soil also make high temperature processing unfeasible.

[kernals12]

This is pretty cool. They can move rock using rapidly expanding plasma rather than dynamite. The advantage is that it is far less risky to people and property nearby.

[Road Hog]

This is pretty cool. They can move rock using rapidly expanding plasma rather than dynamite. The advantage is that it is far less risky to people and property nearby.

This is preferable in highly-populated areas and seems to work. But will it replace old-fashioned TNT in the open? Would like to see what the bang for the buck is (pun intended).

[kalvado]

This is pretty cool. They can move rock using rapidly expanding plasma rather than dynamite. The advantage is that it is far less risky to people and property nearby.

Plasma is a funny word here. Well, whatever it takes to sell...
Alumothery as a (very) slow explosive. I bet efficiency suck, but may be offset by fewer regulatory hurdles.
Termite was long used for rail welding, I wonder if that is still the case?

[Dirt Roads]

Termite was long used for rail welding, I wonder if that is still the case?

Indeed, thermite is still used heavily in the railroad industry.  Other forms of welding can cause significant damage to certain types of track circuits.  Not only did we use thermite for welding sections of rail together, we welded bond wires across bolted jointed and sometimes bonded track circuit wires to the rail (we usually used punch-pin couplers).  But the most interesting use was for welding ground wires and lightning protection to metal structures.  For those of us in railway signalling, thermit welding techniques were most effective for creating a strong metallic bond between dissimilar metals.  (We had to be careful not to "bond" close to certain metals that would cause ionic corrosion).

[triplemultiplex]

The earthen base of a roadway needs time to "settle" because freshly deposited materials will compress under their own weight over time.  We can accelerate the process somewhat by using compaction, but there will still be some settling.  And settling leads to an uneven surface, so one would never be able to plow through a new terrain path and immediately slap pavement on it and expect it to hold up.

One sees this settling phenomenon all the time on newer roads.  You'll be going along on a nice new highway that's maybe only 2-3 years old and suddenly, there's an elongated dip in the road, usually over a culvert or at a bridge abutment.  That comes from not allowing enough time for the material in the subgrade to settle before paving.  The last segment of I-840 to be completed in Tennessee was lousy with these, as an example.  (Might still be, haven't been that way in a couple years.)

For that reason, this super-retro magazine concept would never be a good solution for building roads for reasons completely apart from the crazy logistics it would involve.
Which, by the way, why are they supplying it by helicopter?  It's building a goddamn road behind it, so why wouldn't the raw materials and fuel be delivered by truck?

[kalvado]

The earthen base of a roadway needs time to "settle" because freshly deposited materials will compress under their own weight over time.  We can accelerate the process somewhat by using compaction, but there will still be some settling.  And settling leads to an uneven surface, so one would never be able to plow through a new terrain path and immediately slap pavement on it and expect it to hold up.

One sees this settling phenomenon all the time on newer roads.  You'll be going along on a nice new highway that's maybe only 2-3 years old and suddenly, there's an elongated dip in the road, usually over a culvert or at a bridge abutment.  That comes from not allowing enough time for the material in the subgrade to settle before paving.  The last segment of I-840 to be completed in Tennessee was lousy with these, as an example.  (Might still be, haven't been that way in a couple years.)

For that reason, this super-retro magazine concept would never be a good solution for building roads for reasons completely apart from the crazy logistics it would involve.
Which, by the way, why are they supplying it by helicopter?  It's building a goddamn road behind it, so why wouldn't the raw materials and fuel be delivered by truck?

I can see some exclusions. Going down to rock base - either with thin soil level, or no soil (if we bring up Mars) may reduce settling by a lot.  I wonder if some aggressive compacting - ultrasonic, for example, may also be used.
Permafrost heat transferring bases is another interesting case.
Then there may be something about weak soils, where it's almost a floating bridge - not sure how many such roads are actually there, but I heard about the concept. 

[kernals12]

Did you guys know that you can build roads out of precast concrete modules? I sure as hell didn't. It's much faster than conventional methods. Though I do wonder how they handle it when the roadway isn't perfectly straight.

[kalvado]

Did you guys know that you can build roads out of precast concrete modules? I sure as hell didn't. It's much faster than conventional methods. Though I do wonder how they handle it when the roadway isn't perfectly straight.

To begin with, this is reconstruction - not a green field construction. Makes quite a difference.
And still not the most impressive example of such kind of work