Watching the progress at the bespoke venue in Austin, Texas, was Alexander Rossi, Caterham's 20-year-old Californian test driver.
"I was blown away," he told local broadcaster YNN, "I was almost speechless with how impressive it is because seeing it on paper is one thing, but to be able to actually drive around it, and feel the flow of it and the rhythm of it, and to see the spectacle that is turn one."
Circuit spokeswoman Julie Loignon said work at the venue is "on schedule" for the inaugural race in mid November.
"We're beginning the process known as echelon paving."
She explained that, to ensure a uniform racing surface, three separate paver machines are making three separate laps around the 5.5 kilometre layout.
"The end result is going to be a grade one race track for formula one racing," Loignon added.