(Crackling)
(Thud)
(Laughter)
(Microwave beeping)
You probably all agree with me that this is a very nice road.
It's made of asphalt.
Asphalt is a very nice material to drive on.
But, not always, especially not on days as today,
when it's raining a lot.
Then you have a lot of splashing water on the asphalt,
and especially if you ride your bicycle and cars pass you,
then that's not very nice.
Also, asphalt can create a lot of noise.
It's a noisy material,
and if we build roads, like in the Netherlands,
very close to cities, then we would like a quiet road.
We have solutions for that.
The solution for that is to make roads out of porous asphalt.
Porous asphalt material that we use now
in most of the highways in the Netherlands,
it has pores, and water can just rain through it,
like you see in this image.
So all the rain water will flow away to the side,
and you have a road easy to drive on,
so no splashing water anymore.
Also the noise will disappear into these pores,
because it's very hollow, all the noise will disappear,
so it's a very silent road.
It also has disadvantages, of course.
A disadvantage of this road is that reveling can occur.
What is reveling?
You see that in this road the stones at the surface come off.
So what actually happens, first you get one stone,
then several more,
and more, and more, and more,
and then they --
I will not do that.
(Laughter)
But they can damage your windshield,
so you're not happy with that.
Finally, this reveling can also lead to more and more damage
like you see in the next image,
sometimes you can create potholes with that.
(Microwave beeping)
Hah, it's ready.
Potholes, of course, can become a problem.
But we have a solution.
Here you can see how the damage appears in this material.
It's a porous asphalt, like I said,
there is only a small amount of binder between the stones,
and this binder, due to weathering, due to UV light,
due to oxidation, this binder, this bitumen,
the glue between the aggregates is going to shrink.
And if it shrinks, it gets microcracks,
and it delaminates from the aggregates,
and then if you drive over the road
you kick out the aggregates, which we just saw here.
To solve this problem, we thought of self-healing materials.
If you can make these materials self-healing,
then probably, we have a solution.
So what we do is use steel wool,
used to clean pans, like you see in the picture,
and the steel wool we can cut into very small pieces,
and these very small pieces, we can mix into the bitumen.
Then you have asphalt with very small pieces of steel wool in it.
Then you need a machine, like you see here,
that is used for cooking, an induction machine.
Induction can heat especially steel, it's very good at that.
And then what you do is you melt --
you heat up the steel, you melt the bitumen,
and the bitumen will flow into these microcracks,
and the stones are again fixed to the surface.
Today I used a microwave,
because I cannot bring the big induction machine to heat on the stage,
so I microwaved, it's a similar system.
So I put the specimen in, which I'm going to take out
to see what happened.
I need my gloves again.
This is the specimen coming out now.
We have such an industrial machine in the lab,
to heat up the specimens.
We tested a lot of specimens there,
and then the government, they actually saw our results,
and they thought,
Well, that's very interesting. We have to try that.
So they donated to us a piece of highway,
400 meters of the A58, close to Vilssingen,
where we had to make a test track to test this material.
So that's what we did here, you see where we're making the test road,
and then, of course, this road will last several years,
without any damage, that's what we know from practice.
So we took a lot of samples from this road,
and we tested them in the lab.
So we did aging on the samples,
did a lot of loading on it,
healed them with our induction machine,
healed them, tested them again.
Again broke them, healed them, several times we can repeat that.
So actually the conclusion from this research is that
if you go on the road every 4-years with our heating machine--
this is the big version we have made to go on the real road --
if you go on the road every 4-years
we can double the service life of this road,
which, of course, saves a lot of money.
To conclude, I can say that we made a material
using steel fibers, additional steel fibers,
and using induction energy,
to really increase the service life of the road,
even double the service life,
really save a lot of money with very simple tricks.
And now you're of course curious if it also worked.
So I still have the specimen here, it's quite warm.
Actually it has to cool down first,
before I can show you that the healing works,
but I will do a trial.
Let's see --
Yeah, it worked!
Thank you.
(Applause)