PUBLIC WORKS/Thin treatments extend road life and budget
In recent years, pavement preservation has become the main goal of preventive maintenance work for the Rhode Island Department of Transportation (RIDOT). By using asphalt-rubber repair techniques and other “thin” resurfacing treatments, RIDOT has been able to add life to existing pavement and expects to save money on repairs and labor.
“Rather than having major ‘surgery’ later on, we’re doing this minor preservation work,” says Colin Franco, managing engineer for research, technology and development. Preservation activities usually take place on roads that are five to 10 years old, he explains.
RIDOT regularly examines roads to determine if they are cracking or showing signs of other minor deterioration. When treatment is deemed necessary, one of the first options is to put in a crack seal, Franco says. Workers dry the area and remove particles, then apply a soft rubber sealant.
If damage is more severe, crews apply an asphalt-rubber chip seal, which can be used on large resurfacing jobs in hot mixes or as spray-applied membranes. RIDOT is using the asphalt-rubber only in heavily trafficked urban areas or in very rural areas because the material produces an extremely hard surface. Franco says the department does not want to use it on residential streets where children could fall and hurt themselves. “It’s too rough,” he explains.
Thin treatments that do not involve a lot of time or effort, such as crack seals, asphalt-rubber chip seals, slurry seals and microsurfacing, are encouraged by the Federal Highway Administration (FHWA), Washington, D.C., accordi ng to Jim Sorenson, senior construction and preservation engineer for FHWA. “We have got to start doing more preventive maintenance,” he says. “Preservation techniques help to extend the life of roads.”
FHWA has been working with state DOTs for the past five years to educate them about preventive maintenance techniques. Those methods can extend pavement life by five to six years and make highway funding stretch further, Sorenson says.
“States, cities and counties spend $120 billion on highway work each year,” he notes. “If we dedicate more funds to preservation, we could double the money [for other projects].” In addition to saving money for materials, asphalt-rubber treatments save labor costs because they do not take long to apply. “Thin treatments can go down quickly, often overnight,” Sorenson explains.
RIDOT started using asphalt-rubber products from All States Asphalt, Sunderland, Mass., last year. Franco says it will take two or three years to fully evaluate areas where the material has been used, but the technique is working well so far.