The special track surface in Miami turned out to be more tricky than expected

After practice sessions the asphalt in turns 7 and 17 had to be fixed twice.

We have seen some drivers losing the control of their cars, and the track surface surely could be one of the reasons. What is more, many drivers said the track is hard to race on. 

Sergio Perez:

“As soon as you go off-line, there is no grip, it’s done. It’s sometimes wet on that side and sometimes off-line, it feels very gravelly so racing will be hard.”

 Lando Norris:

“The surface is very tricky, you go off-line anywhere and it’s pretty much game over, you spin, you end up in the wall. It’s punishing. That’s why you’ve seen a lot of people ending up in the barriers.“

The asphalt on the Hard Rock Circuit is different to what f1 circuits usually had. 

Sam Worthy, the project director, shared many insights about the surface in Miami—

“Of course, a lot of engineering and analysis has gone into the asphalt itself."

“We’re starting to see the limerock aggregate peek through right now because we’re getting that top layer of binder coming off now. You can see white specks in it.

Normally, limerock is a poor aggregate to use for F1 tracks: one, it is ‘friable’ and can chip and, two, it polishes. So you don’t usually get good tyre degradation and grip is reduced. But, in Southern Florida, the predominant aggregate is a more abrasive limerock."

“Our asphalt specialists, R3, looked into the local aggregate and they said they’d seen nothing like it throughout the world, as it is much harder than expected and will result – with the mix of 60% US-mined granite from Georgia – in suitable abrasiveness in our asphalt mix. R3 has been involved with most recent F1 tracks in some way, so their exposure to data from other venues gives us a good reference.

What R3 found in South Florida is that ‘our’ limerock is unique because it has a very high silica content. Its texture is like little shards of glass, so as the limerock itself breaks down and degrades it exposes more of this silica and so you get an effect where it maintains a much higher tyre degradation than you’d usually get in with limerock elsewhere in the world."

“Granite was brought by train from Georgia, and so our mix is an innovative combination of granite and limerock that is all locally sourced – it’s nowhere near what people thought we’d have originally. We are very pleased with the results we’ve got.”