Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/85927
RoadScience drocarbons, and resins, the scanning tour report states. It's a fossilized plant wax, also known as lignite wax or OP wax, obtained by solvent extraction from certain types of lignite or brown coal. Its melting point is 180 to 200 deg F, and Asphaltan-B is a trade name for this type of additive. Injection of water, along with the liquid asphalt cement, causes the liquid asphalt to foam and expand in volume. Different from the waxes are the surfactants, such as Evotherm and Rediset. We have shown how important surfac- tants are for manufacturing asphalt emulsions (see Spread- ing the Wealth: Asphalt Emulsions Mix Oil with Water, June 2012, pp 18-29). Evotherm is a chemical compound with surfactant activ- ity, which adds lubricity to individual microscopic asphalt particles. The particles or micelles develop "slip planes" that let the asphalt particles move more easily, requir- ing lower levels of energy. Because the energy is lowered, Evotherm warm mix has the same viscosity properties at lower temperatures as conventional hot mix asphalt. Rediset-LQ is another product. Water-based, in-plant foamed systems for low energy mixes – such as the Astec Industries, Inc.'s Double-Barrel Green System – use nozzles that precisely meter water into the drum of a drum mix plant. Injection of water, along with the liquid asphalt cement, causes the liquid asphalt to foam and expand in volume. The foaming action helps the liquid asphalt coat the aggregate at a temperature that normally is in the range of 230 to 270 degrees F. A much different kind of foamed asphalt incorporate liquid "foamed" asphalt as a stabilizing agent, in which hot-liquid asphalt is foamed with water and air, and is then Booth # 601 Write 118 on Reader Service Card or visit www.betterroads.com/info Cimline_BR0812pg22.indd 1 22 August 2012 Better Roads 7/24/12 9:48 AM