26 replies to this topic

[zac510]

Does anybody have a close-up picture of this Indianapolis 'diamond ground' surface?

Is it noticeably different to the eye?

[OfficeLinebacker]

Is this the same thing as levigation?

[OfficeLinebacker]

Hmm levigation seems to be a similar process only using strong jets of water.

[zac510]

It's been used at Indy for a few years at least, to my knowledge, but reading about it today it occurred to me that I had never actually seen it!

[Tony Matthews]

Hmm levigation seems to be a similar process only using strong jets of water.

[Ciro Pabón]

Hmm levigation seems to be a similar process only using strong jets of water.

No. Levigation is a tool to cut through concrete.

Diamond grinder is a fancy name for a tool called a "cold planer" (I think. In spanish, my native language, is called a "fresadora de asfalto" or "asphalt burr").

It's a simple machine having a cylinder with points that scrubs the asphalt. The cylinder is used in an horizontal way, not vertical like in the picture:

Asphalt burr for removing the top layer. A "finisher" diamond grinder has smaller points


When recently grounded, the surface has traverse scratchs that help to improve grip. In an asphalt surface, after a little use, it looks like this:

Indianapolis diamond grinded surface after a while


The main difference (you have to go on your knees and touch it to notice it) is that the rocks are cut instead of broken, so the polish they get with time is done with. When you use it in concrete asphalt, the scratches last more time.

You use it to elliminate the "hard heads" in old asphalt. By this I mean that, with time, the surface asphalt disappears, so the rocks protrude (what is called "hard heads"), like this:

Old asphalt with hard heads


The level of smoothness that can be achieved through diamond grinding is equal to or better than that of a new pavement or overlay. You can control in a better way the sideslope for draining. A recently grinded surface is hard on tyres, specially on race tyres.

Hi, Zac, is that you?

Edited by Ciro Pabón, 08 June 2009 - 21:11.

[OfficeLinebacker]

No. Levigation is a tool to cut through concrete.

Diamond grinder is a fancy name for a tool called a "cold planer" (I think. In spanish, my native language, is called a "fresadora de asfalto" or "asphalt burr").

It's a simple machine having a cylinder with points that scrubs the asphalt. The cylinder is used in an horizontal way, not vertical like in the picture:

Asphalt burr for removing the top layer. A "finisher" diamond grinder has smaller points


When recently grounded, the surface has traverse scratchs that help to improve grip. In an asphalt surface, after a little use, it looks like this:

Indianapolis diamond grinded surface after a while


The main difference (you have to go on your knees and touch it to notice it) is that the rocks are cut instead of broken, so the polish they get with time is done with. When you use it in concrete asphalt, the scratches last more time.

You use it to elliminate the "hard heads" in old asphalt. By this I mean that, with time, the surface asphalt disappears, so the rocks protrude (what is called "hard heads"), like this:

Old asphalt with hard heads


The level of smoothness that can be achieved through diamond grinding is equal to or better than that of a new pavement or overlay. You can control in a better way the sideslope for draining. A recently grinded surface is hard on tyres, specially on race tyres.

Hi, Zac, is that you?

You, sir, are fvckin' awesome.


Yeah in retrospect I think levigation simply indicates how insoluble powder is washed away after being ground off or whatever.

Anyway, got more pics?

[Tony Matthews]

And there's me thinking you were being witty! Won't get fooled again!

[OfficeLinebacker]

And there's me thinking you were being witty! Won't get fooled again!

Yeah but isn't unintentional wittiness the best kind?

[Tony Matthews]

Yeah but isn't unintentional wittiness the best kind?

Only if you mean it.

[zac510]

Yes it is me, and I should have known you'd know about this stuff, being a road/transport engineer!

You get a reasonably good idea from that 2nd pic, it looks like very well worn road tarmac but without the cracks from its movement.

What part of it exactly cuts up the tyre, is it the fact that the cutting leaves a sharp edge where the head has been cut or is there some funny vibration generated when the tyre slides?

Edited by zac510, 09 June 2009 - 08:27.

[Tony Matthews]

Yes it is me, and I should have known you'd know about this stuff, being a road/transport engineer!

You get a reasonably good idea from that 2nd pic, it looks like very well worn road tarmac but without the cracks from its movement.

What part of it exactly cuts up the tyre, is it the fact that the cutting leaves a sharp edge where the head has been cut or is there some funny vibration generated when the tyre slides?

Some years ago I had a Ford Anglia running on wide Miniliites and Goodyear racing tyres ('Not for highway use') and having completed some mods. took it for a late-night test run including a section of M1 Motorway. Everything seemed fine until I hit the M1, when a terrible howl filled the car, every bare panel singing and vibrating. I stopped on the hard shoulder and got out to peer underneath. As I was on my hands and knees looking for any clues I heard a similar but fainter wailing, and a solitary car cruised past a couple of lanes away. 'That's odd!' I thought. Then another car passed emitting the same noise. My attention turned to the road surface, and there was the answer - it had been grooved since I had last taken that route, and it was this that was causing the vibrations.

[Ciro Pabón]

...My attention turned to the road surface, and there was the answer - it had been grooved since I had last taken that route, and it was this that was causing the vibrations.

Great example, Tony. That happens in concrete pavement.

Diamond ground concrete pavement


Zac, the wearing (in asphalt pavement, like Indy) is caused by microtexture of the aggregate (the rocks). You need a microscope or a magnifier to see it.

Quartzite, diamond grinded (the picture is 15 mm across).


Those rough edges are what kill your tyres, but not for long: they are abraded more or less quickly, in one year or so. Even without cars passing, the rain water hydrates the silicates.

As I've said elsewhere, stones from a river beach are the worse (they are what's left after all the soft rocks have been dissolved by water). Stones from a quarry are softer.

A good racer (or a paranoid one, I'm not sure) can distinguish both types: rocks from a river have some rounded faces left after being crushed for pavement making.

Rocks from a quarry (like the picture I posted before for "hard heads") are more or less cubic.

Anyway, it's the rocks. Few people realize than 95% of an asphalt pavement is rocks. The black gooey thing (asphalt) is only 5%.

In concrete pavement (like the one I suspect Tony was riding), the edges of grooves are also important, but that doesn't happens at Indy.

BTW, I resent being called an engineer: I mainly write poetry... even when I build a road.;)

Edited by Ciro Pabón, 09 June 2009 - 18:43.

[Tony Matthews]

In concrete pavement (like the one I suspect Tony was riding)

The event I mentioned happened about forty years ago, CP, and it probably was concrete at that time - they grooved it as it had become polished and there had been several accidents, especially in the wet. I think all British roads, of all classes, are now tarmac, though I could be wrong.

[OfficeLinebacker]

I've read before that, Darlington I think, was particularly abrasive because of SEA SHELLS embedded in the asphalt. So that would be some really insoluble stuff, for sure! Also makes sense that it would not only remain abrasive, but become more abrasive over time as more of the interstitial stuff got eroded away.

Good stuff, ingeniero poetico!

[zac510]

I was in the Western Sahara last year and noticed they used a lot of sea shells and stuff as the aggregate (is that the right word for the filler?). They used it in all concrete, walls, footpaths, anything!

[Demo.]

Hmm levigation seems to be a similar process only using strong jets of water.

Levigation is the process of grinding an insoluble substance to a fine powder, while wet.
So unless you wanted to destroy a track you would never levigate it.

[jdanton]

I've read before that, Darlington I think, was particularly abrasive because of SEA SHELLS embedded in the asphalt. So that would be some really insoluble stuff, for sure! Also makes sense that it would not only remain abrasive, but become more abrasive over time as more of the interstitial stuff got eroded away.

Good stuff, ingeniero poetico!

Great thread. I always thought Darlington and Rockingham were so hard on tires, because the soil in the region is all sand. When the wind would blow through the course of the year, the track would basically get sandblasted. I have a (non-digital) pic of the surface at Rockingham, there are no shells to be seen, but the aggregate is extremely coarse.

I've also ridden bicycles at Charlotte Motor Speedway, which seemed to have a fairly normal asphalt surface.

[OfficeLinebacker]

Levigation is the process of grinding an insoluble substance to a fine powder, while wet.
So unless you wanted to destroy a track you would never levigate it.

Ever stop to think that maybe just the very top surface would be levigated? Like basically the same thing as diamond grinding, only while being washed with water? Who knows maybe diamond grinding happens with a water rinse and they really are the same thing.

Tracks have been levigated before and not been destroyed.

[OfficeLinebacker]

Great thread. I always thought Darlington and Rockingham were so hard on tires, because the soil in the region is all sand. When the wind would blow through the course of the year, the track would basically get sandblasted. I have a (non-digital) pic of the surface at Rockingham, there are no shells to be seen, but the aggregate is extremely coarse.

I've also ridden bicycles at Charlotte Motor Speedway, which seemed to have a fairly normal asphalt surface.

I'd be interested in those pics if you could scan then.

[jdanton]

I'd be interested in those pics if you could scan then.

I'll track them down..

[OfficeLinebacker]

Thanks jdanton!

Just heard that there are some NASCAR Cup tyre tests at Indy Monday & Tuesday, twelve teams expected to participate.


I believe this will be the last, crucial test before the race.

[Demo.]

Ever stop to think that maybe just the very top surface would be levigated? Like basically the same thing as diamond grinding, only while being washed with water? Who knows maybe diamond grinding happens with a water rinse and they really are the same thing.

Tracks have been levitated before and not been destroyed.

It may be a sub-process related to levigation but unfortunately levigation is not the smoothing of a surface.
It is the complete reduction of an substance to a powder with water.
Levigation
Levigation is the process of grinding an insoluble substance to a fine powder, while wet. The material is introduced into the mill together with water, in which the powdered substance remains suspended, and flows from the mill as a turbid liquid or thin paste, according to the amount of water employed. There is no loss of material as dust, nor injury or annoyance to the workmen. Further, any soluble impurities in the substance are dissolved, and the product thereby purified. 'the greatest advantage of this process is the facility it affords for the subsequent separation of the product into various grades of fineness, because of the slower subsidence of the finer particles from suspension. The turbid liquid, flows into the first of a series of tanks, and is allowed to stand for a certain time. The coarsest and heaviest particles quickly subside, leaving the finer material suspended in the water, which is drawn from above the sediment into the next tank. The liquid is passed from tank to tank, remaining in each longer than it remained in the preceding, since the finer and lighter the particles, the more time is necessary for their deposition. In some cases a dozen or more tanks may be used, and the process then becomes exceedingly slow, as very fine slimes or muds may require several weeks for the final settling.
But as a rule, from three to five days is sufficient. The term "levigation" is now often applied to mere sedimentation, a substance being simply stirred up in water, without previous wet-grinding, in order to separate the finer from the coarser particles, as above.


the above quote is from
http://www.lenntech....i...0ISpZISS6

just do a google search on levigation
Edit add
The Engineer's And Mechanic's Encyclopaedia defines levigation as
The art of reducing hard bodies to an impalpable powder; it is performed by pounding, rubbing, or grinding; or by a combination of these operations.
Once again it is clearly the whole not part that is reduced to powder and includes no smoothing of anything

perhaps any tracks which said they levigated their tracks misused the word for a simular process of grinding with water but levigation is a clearly defined process that would be of no use to a race track.
perhaps you could post some tracks that say they were levigated?

Edited by Demo., 15 June 2009 - 03:15.

[Canuck]

Or we could all stop being pedantic about things and let them lie.

[OfficeLinebacker]

For the sake of completeness.

http://msn.foxsports...3...162&ATT=167

and here's one where the diamond grinding is considered synonymous with levigation:

http://dic.academic....f/enwiki/358244

"In 2005, the surface of the circuit had started to wear from its last paving in mid-1994, resulting in the track's treatment in a diamond-grinding process to smooth out bumps. This process, known as levigation, caused major tire problems"

and here's one basically saying the same thing about Indy:

http://community.fox...problem_at_INDY

Frankly I think the terms are compatible; you can imagine the dust and heat that would be created if the surface weren't irrigated during the grinding process.

Now I know why I thought it was the same thing; I must have read it in articles around the time LMS was re-done.

Edited by OfficeLinebacker, 15 June 2009 - 05:12.

[Demo.]

Thanks for the links.
I stand by the fact of a technical term has been used incorrectly (due to the fact that diamond grinding does not create a truly smooth surface but ends up with V shapes cut in the surface as per pictures earlier in the thread and as stated in one of your links)
As shown most clearly in this picture posted earlier in the thread


Either way is it not part of how a language evolves over time what was once clearly not what was meant by a word gets changed through popular usage overtime to enhance the meaning and include what was once excluded.

Or perhaps it is just one of the differences between two lands with a common language but such different useages as my useage was British based and i know your examples were USA based.

Either way its a new useage of the word for me and one i will take on.

Thanks for the time taken to post the links and the information.

Edited by Demo., 15 June 2009 - 07:18.

[Rosemayer]

When I was in Guam in 1967 the highways had asphalt mixed with ground coral as no gravel was avalible.Excellant dry grip very abraisive but in the rain it would become slimey and slick as snot.Agood friend of mine was riding his Norton Commando and hit a wet spot his leg was under the bike and he lost part of his ankle bone along with a massive bone marrow infection.He survived but was in the hospital 3 months.