Fontaine smoothes the way for the Indy 500The Indianapolis Motor Speedway was refurbished last fall, and Robin Fontaine '90 was on hand to watch as the drainage system and custom asphalt mix she designed were installed. The 2.5-mile racetrack, home of the Indianapolis 500 a nd other auto races, was last resurfaced in 1988; it had been completely repaved only twice since it first opened in 1911.
Fontaine, a mix design engineer who oversees the bituminous mix lab at Heritage Research Group in Indianapolis, began taking core samples of the 15-inch-thick pavement in June. Her analysis revealed that the Speedway was sorely in need of a formal drainag e system to eliminate "weepers" -- pockets of trapped moisture that leaked down to the clay shoulder and were forced back up to the surface by hydrostatic pressure. Working with two assistants, she designed an under-track drainage system to collect water and channel it to tile drains on the inside edge of the track.
Core sampling revealed cross sections of the Speedway's multilayered history. Originally a bed of crushed stone sealed with a bitumen coat (which turned out to be a complete dud when the first race was held), the track was revamped for its second race wit h a 4-inch layer of sand and 3.2 million paving bricks. Layers of asphalt were added over the years.
To make the world's smoothest racetrack even smoother and more durable, Fontaine designed an improved surface course with two specialized paving materials. A thick layer of MAC -- multigrade asphalt cement (MG 10-30) -- was applied over the drainage aggre gate. Like the "10-40" multigrade motor oils that lubricate automobile engines, MAC is formulated to maintain its viscosity though extremely high and low temperatures.
Fontaine's aggregate structure uses a performance-grade asphalt binder called PG 64-34, which had proved itself in five-year tests against rutting, thermal stress and fatigue cracking. The binder is rated to stand up to bitter Indiana winters at 29 degree s below zero and to remain stiff at temperatures up to 147 degrees. Pavement temperatures in the low 140s have been recorded in August, when the Brickyard 400 race is held.
The most time-consuming part of the resurfacing project was milling off 30 inches of the original pavement. About 17,000 tons of material was removed; it will be crushed, rejuvenated and recycled to create new parking lots for Speedway patrons. The 3-foot start/finish line, known to racing fans as the "Yard of Bricks," was also milled and restored, using bricks from a stockpile of the original 1911 paving bricks.
Fontaine, a varsity track and cross-country team member at WPI, admits that growing up in New England did not prepare her for the Midwestern passion for auto racing.
"When I was back in Massachusetts, I couldn't stand watching the Indy 500 on TV. It was so boring! Nothing ever happened, just the lead car going round and round," she says.
Then Fontaine moved to Indiana in 1993 to earn a master's degree in civil engineering at Purdue University. The first time she saw a live race, she was converted. "It's so different, being at the track, from seeing it on TV." She's been a regular at the r ace ever since. This year she'll be watching the performance of her track, as well as the drivers, and hoping some new speed records can be set with the smoother pavement.
Fontaine will experience the full impact of her work this spring when she runs in the mini-marathon, held as part of the "500 Festival" each May. The course starts in downtown Indianapolis, proceeds to the Speedway, and circles the oval for two miles befo re returning to town. She'll actually have a chance to race on the surface she designed. We wish her a smooth run.
-- Joan Killough-Miller
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