In this photo, a granite curb is seen on the UConn campus. The university’s granite curbs were installed between 1995 and 1996 as part of the UConn 2000 plan under President Harry J. Hartley. (Rebecca Newman/The Daily Campus)
The University of Connecticut’s granite curbs were installed between 1995 and 1996 as part of the UConn 2000 plan under President Harry J. Hartley. Granite is more durable in comparison to more traditional Portland cement concrete, but it’s less forgiving on car tires.
“Lab tests have shown that granite is stronger, and more resistant to the elements,” according to “Structural Analysis Comparison: Granite and Precast Curbing,” prepared by the Department of Civil Engineering at the University of Massachusetts at Amherst and distributed by the American Granite Curb Producers.
Curbs are multifunctional. They deter vehicles from leaving the street, support sidewalks and control the flow of drainage.
Studies for the same report showed that both types of curbing can endure 450 cycles of freezing and thawing, but only granite can survive without “sharp deterioration in appearance; particularly the corners and edges.”
Granite curbs are also more easily recycled than concrete.
“Reuse of granite is enhanced as it can be cut into different widths and shapes,” said the report.
An economic analysis in the same report also showed granite to be a more cost-effective material.
The primary downside of granite is its danger to tires as a result of its greater durability. An article by Cathy Woodruff for the Timesunion called them “a menace to tires” and “harder than they look.”
Granite is much more likely to “withstand impact” with a tire, according to the UMass report.
“That [the granite] looks like it would pop my tire,” said Riley Pflomm, fifth semester physiology and neurobiology major.
Concrete, by contrast, is less likely to pop a tire.
“I prefer the concrete curbs,” said Emma Bee Schwarz, third semester psychology major. “The granite ones get slippery.”
“I think the granite just looks better,” said Joey Fong, fifth semester political science and economics major, “I’m very confident that I could avoid popping my tire.”
The same report from UMass noted that curbs are expected to last for generations. Physical comparisons between granite and precast Portland cement concrete (PCC) curb indicate that granite is a superior curb material. An economic analysis further determines that granite curb also is a cost-effective curb material.
“Although the cost of precast PCC curb is less than that of granite curb, granite’s durability, longevity and reusability negate the cost advantage of precast PCC”
While the granite curb showed no adverse effects, precast PCC curb subjected to salt exposure and repeated freeze/thaw cycles during lab tests deteriorated around the edges.
Curbs deter vehicles from leaving the pavement, control drainage and support the edge of the pavement. It should be noted that once established, most roadways remain unaltered for generations. Therefore, curbs are expected to serve long lives. They must be durable, and at the same time economical.
The principal factors that affect the life span of curbs are loads, impacts, and the elements. The most destructive elements in the Northeast, as previously stated, are salt and freeze/thaw action.
Lab tests have shown that granite is stronger, and more resistant to the elements, than precast PCC. Granite curb is routinely salvaged and reused. Granite curb also withstands road milling, a common maintenance technique. Granite curb can serve a nearly indefinite life – at least by human standards.
Concrete curbs also deteriorate more quickly than granite in de-icing salts.
Christopher McDermott is a campus correspondent for The Daily Campus. He can be reached via email at christopher.mcdermott@uconn.edu.