Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/85919
oxides) – in the presence of sunlight – to form ground- level ozone or smog. And the solvents used can be highly flammable and evaporative fumes can cause irritation among workers. Like asphalt emulsions, cutback asphalts are classified as rapid-, medium- and slow-curing. Solvents used include gasoline for rapid-curing, kerosene for medium-curing, and diesel fuel for slow-curing cutbacks. Likewise, pavement sealants or asphalt emulsions con- taining coal tar are losing favor and actually are targeted by legislation. For example, a bill introduced in the California Legislature in February would ban the sale and use of pave- ment sealant products that contain coal tar, classified as a carcinogen in high concentrations. Sealants that use coal tar are in use in other states, primar- ily on the East Coast, and a bill to ban them nationwide, H.R. 4166, was introduced earlier this year in Congress by U.S. Rep. Lloyd Doggett (D-Texas.) Engineered Rejuvenators Rejuvenators are engineered cationic emulsions containing liquid asphalt components of maltenes and saturates (light fractions). They soften aged, stiffened, oxidized asphalt pave- ments, fluxing or fusing with the existing asphalt binder, changing the properties of the asphaltic concrete, quelling aggregate loss and extending surface life According to manufacturer Tricor Refining, its Reclamite rejuvenator increases penetration values and reduces viscos- ity values. The rejuvenator, which is sold under the name Reclamite, seals out moisture and restores the asphaltene/ maltene balance lost due to aging and oxidizing by replen- ishing the maltenes. The rejuvenator's natural solvency is attributed to its naphthenic base. The rejuvenator is spray-applied. The emulsion is diluted 2:1 (product to water) or 1:1 with water. Application rates are measured in square yards or meters and vary according to pavement absorption and application needs. In 2005, Travis County, Texas, looked at the use of a maltene-based rejuvenator to improve and preserve its oxidized, cracked Type F mix low-volume street and road pavements. The county placed several full road-width test sections of the rejuvenating agent. They saw excellent absorption and penetration into the binder. Tests showed that the rejuvenator was fluxing with the binder, and results indicated a decrease in micro-viscosity of the binder in the range of 60 to 300 percent, along with a corresponding increase in penetration values. The subdivision streets are vacuum-swept in 24 to 48 hours after application. A bonus is that because the rejuvena- tor does not contain asphalt, coal tar base or gilsonite, any tracking is kept to a minimum with little or no residential complaints. © 2011 Highway Equipment Company. All rights reserved. Write 112 on Reader Service Card Better Roads June 2012 29