Commenting about Draining Asphalt Pavements

in hive-175254 •  4 years ago 

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The design and construction of pavements is one of my favorite subjects, in fact, it is one of the subjects that I teach at the local university where I work in Venezuela.

And I remember that twenty years ago, the issue of "draining pavements" was not mentioned as often as it is now, in fact, I don't even think they existed, at least not like they are now.

The fact is that on one occasion at an international asphalt congress (8 years ago), one of the speakers from Mexico presented us as a novelty the construction of draining pavements in his country, it is still wonderful, but the story does not end here.

I remembered by casually that in 2009 the new regulation for road construction was approved in Venezuela, known as NTF 2000-1 Roads, Highways and Urban Roads - Specifications and Measurements, these regulations establish the new standardized asphalt mixtures (for Venezuela), still in force to this day. And in these different asphalt mixtures stand out, ranging from the most permeable that allows the passage of water, to the most impermeable, and here my story begins.

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First of all, what is a drainage pavement?

It is simply a pavement of asphalt origin, also called flexible pavement, which has the ability to allow the entry and exit of rainwater through the interstices of the asphalt mixture, so that it travels to the existing drainage structures in the road, be it gutters or canals.

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The paradox is that common asphalt pavement and water "are not good friends", because when this pavement receives rainfall, if it does not receive proper maintenance, it eventually loses its properties and may present structural failures where the base layer and the sub-grade soil lose stability due to the presence of water inside, soon deteriorating and ending their useful life.

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How is a drainage-type asphalt pavement achieved?

This is a great technical advance, but it is not entirely new, this has been around for some time without knowing that this draining capacity would be one of its benefits.

To achieve a draining asphalt pavement, an asphalt mixture with an "open" granulometric structure must be used, where interstices that we can define as "pores" are appreciated, where rainwater enters and leaves easily due to the transverse slope of the road, this water "runs" to nearby drainage structures by the effect of gravity.

But this is not enough, it is assumed that the asphalt mixture together with the pavement structure must be able to resist wear due to the passage of vehicles and at the same time it must resist the effects of repetitive loading of these vehicles. For this, the granulometric structure of the asphalt mix must have a high-strength coarse aggregate.

"This is wonderful, this is amazing, this is the" ideal pavement ", in my opinion

One of the most important advantages is the reduction of the “aquaplaning” effect, that is when vehicles skid on wet pavement, this effect is reduced when rainwater is dislodged through “the pores of the asphalt mixture”.

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But not everything is perfect, there are also some disadvantages

The most notable disadvantage is the need for more frequent maintenance routines than usual, because the pores in the asphalt mix can be clogged with fine materials such as dust or sand and must be removed using high-pressure water jets. And like all asphalt roads, it is also necessary to apply reinforcement layers.

This is not so economical but it is better than traditional pavement.

Where is the coincidence I mentioned earlier?

The coincidence is that as I mentioned, in Venezuela there has been officially since 2009 the rules and regulations for the elaboration of asphalt mixtures of the draining type and of the normal type, that is to say of "open granulometry" and "closed granulometry", the great detail is that our asphalt pavements are not being built with this type of mixture.

This is an issue that I have discussed with many contractors in my city when I have had to audit their projects or constructions, and I find that most of the time it is due to ignorance of current regulations and on other occasions due to negligence.

On other occasions, I have participated in highway and highway construction projects, where luckily if current regulations have been used and I can say that despite being "test sections" the results were as expected.

In conclusion, in Venezuela the existence of draining pavements is not a novelty, they already exist in our regulations and construction specifications, what happens is that they have not been built for this purpose, and about this I have many things to comment and tell, but it will be in another post.

If you've ever had the opportunity to travel by road, do you think it will be worth building draining asphalt pavements?

I see it very easy, but I want to know your opinion ..!

"All the text has been written according to my professional experience as an engineer, university professor, researcher and developer of engineering projects."

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@tipu curate 3

Thanks friends..!

Hello friend, hey interesting information, I imagine that maintenance must be present because otherwise I guess the deterioration will be unstoppable, I imagine that's why the holes are formed in the roads. And of course, this can lead to other consequences such as accidents, in our country it is more than evident that this is not at all important for the government or municipalities. And not only in our country there are others that go through the same situations.

It is always good to learn something new, thanks for educating us. Greetings!

Hello @franyeligonzalez, your'e right..!

Lack of maintenance is the main cause of the appearance of faults in the scarves and rainwater causes great damage to the pavement.

Thanks for you comment..!

See you soon

Hello @tocho2
I know that pavement is a big topic, but from a technical point of view I don't know much about it, however I can say as a road user that it really is of vital importance for any road to have a good pavement. Those characteristics that you mention of the pores and that allows the passage of water, I think it could dismnuir accidents as it would keep the road dry.
I imagine it must be much more expensive to make, but in safety matters it is worth it.

Hello @josevas217, certainly the draining pavement allows the road to always be dry, and the worst of the case is it is not expensive at all, it is a common type of asphalt mixture, only that it is not used in Venezuela even though we have it standardized.