The 73-story hotel and office tower in downtown Los Angeles will become the highest building west of the Mississippi once it's completed.
"The Wilshire Grand has the largest continuous concrete pour of 21,200 cubic yards which is a new Guiness World Record's title. Congratulations!" said adjucator Michael Empric during a meeting with contractors and engineers.
The concrete was poured by 11:30 a.m. Sunday, beating the existing record of 21,000 cubic yards set by The Venetian hotel in Las Vegas in 1999. The record was marked by blaring horns.
"This is basically a huge milestone project in itself as now it's the foundation to start rising this iconic tower down here in downtown Los Angeles," said VP Construction executive Scott Borland.
The new Wilshire Grand project will peak L.A.'s skyline at 1,100 feet.
Korean Air is behind the $1 billion development, and say a good portion of that money was spent on concrete trucks. Each truck made ten deliveries, hauling in more than 21,000 cubic yards of concrete - that's equivalent to 82 million pounds of concrete.
The grand pour began Saturday with a special ceremony involving L.A. Mayor Eric Garcetti. About 20 hours later, the record for longest concrete pour was set.
"What that means is that the concrete hasn't set up at any point, so they just keep on pouring all night until they get to their final number," said Empric.
The new Wilshire Grand Center will feature five levels of underground parking, convention space, office suites and 900 hotel rooms.
The project is scheduled to open in 2017.
Parts of Figueroa Street, 7th Street, Wilshire Boulevard, and Francisco Street that were closed for the record-breaking pour have since reopened.
CNS and The Associated Press contributed to this report.