Elvaloy Enables South Dakota Warm Mix Asphalt Trial
BY Dow
A number of technologies are being used that allow hot-mix asphalt (HMA) producers to lower temperatures. Benefits of these technologies include reduced paving costs, extension of the paving season, improvements to asphalt compaction, and improved environmental, health, and safety from reduced emissions, fumes, and odors. The additive ELVALOY™ Reactive Elastomeric Terpolymer (RET) from Dow, headquartered in Midland, Michigan, is one such technology.
“Elvaloy RET is used to create polymer modified asphalt (PMA) as well as recycled plastic modified asphalt (RPMA),” a spokesperson explained. When used on a 2018 field trial of Elvaloy RET with the South Dakota Department of Transportation, the additive succeeded in keeping mix production and delivery temperatures of a polymer-modified mixture from rising into typical PMA zones. Take a look at this case study provided by Dow.
The contractor milled 2 inches depth along Highway 42 in McCook County. Commercial Asphalt then paved a 2-inch overlay with Elvaloy-modified asphalt.
Jebro Incorporated blended approximately 250-275 tons of PG64-28 binder modified with Elvaloy RET. The Jebro team that prepared the commercial blend has significant experience with the additive at other locations (technical, operations and QC).
“Jebro was happy with the ease in processing Elvaloy RET in the asphalt mix,” said Kevin Carlson, general manager research & development and quality control at Jebro. “We did not have to make any special changes to our process to use Elvaloy, and it is performing as expected.”
The PG64-28 met AASHTO M 320 specifications as well as the minimum elastic recovery requirements as outlined in section 890 of the 2015 Standard Specifications for Roads and Bridges. Commercial Asphalt used the modified binder to pave approximately 2,300 tons of base mix and then paved approximately 2,300 tons of surface mix.
The liquid asphalt was stored at 310 degrees F with mix production temperatures ranging between 290 and 310 degrees. A spokesperson for Dow said the temperature was maintained to the paving site.
Dow has continued monitoring and working with its partners on this South Dakota project, noting that the use of Elvaloy RET offered benefits for both South Dakota and its contractors. As an alternative to SBS-type modifiers, it is designed to meet the current binder and mix specifications, as well as fatigue cracking and stripping. The pavement with Elvaloy RET-modified binder has performed well over time, showing similar results to that of SBS. It was processed as warm mix asphalt and therefore provided benefits such as reduced costs, improvements to asphalt compaction, and so on.