| APPLICATIONS RESILIENCY Improving resiliency is a key to increasing long and short term asphalt performance, and elastomeric modification of asphalt oil is being done through out the world. Ultracote adds more resiliency to the hot mix as a stress absorbing membrane interlayer (SAMI). The Ultrapave team are concentrating on this area for advances in the future. ANTI-STRIPPING ULTRACOTE is an excellent anti-strip agent because it has a high affinity for asphalt. Preventing the stripping of asphalt binder from the surface of aggregates is extremely important in extending pavement life and many millions of dollars in maintenance work can be saved each year. THERMAL CYCLING Two to three pounds of Ultracote per ton of aggregate will provide a stress absorbing polymeric layer on the aggregate, thereby reducing damage due to thermal cycling. When properly applied it will turn a hydrophilic aggregate (likes water) into a hydrophobic aggregate (hates water), increasing the water resistance of the hot mix. Thermal cycling is one of the most powerful forces of erosion. Heating and cooling causes damage to pavements when the water expands and contracts in the pores. Water can wedge into rock through fissures or cracks and damage to roadways occurs as this force breaks down the aggregate and the bond between the rock and asphalt oil. ULTRACOTE polymeric aggregate treatment is the ingredient used for each of these applications. The primary difference between them is the dilution of the material used. For a complete discussion of the construction and laboratory procedures, request the separate documents from Ultrapave. |
THE ALASKA EXPERIENCE
In the summer of 1995 Seacon Construction of Juneau paved two projects using the same mix design, oil supply, aggregate source, paving crew and paving procedures. The first was Loop Road, a three mile section of highway from the Juneau Airport to the Mendenhall Glacier. The second was Egan Drive, a six mile section from the Juneau Airport to the state capitol area downtown. The aggregate for the Egan Drive project was treated with 0.335% ULTRACOTE, while the Loop Road aggregate was untreated. In the winter of 1995, the temperature in Juneau dropped to a low of -20° F for five days. Then it warmed up to +38° F and rained. Talk about a giant modified Lottman stripping test! The untreated Loop Road project showed many incidents of thermally induced cracking. However, the Ultracote-treated Egan Drive project showed very few. This field project seems to validate the added benefit of resistance to thermal cracking by ULTRACOTE. |
