VAASPHALT.ORG 27 Reference 1. See the National Asphalt Pavement Association’s IS52 and TAS22 publications for more. if it is pushed over the edge of the pile. Instead, lifting and placing the aggregate by either a rubber tire loader or track hoe is a better approach, resulting in the least aggregate segregation. However, care must be taken not to build tall, steep conical stockpiles where the large rock will tend to roll to the outside edge of the stockpile. Likewise, it is vital to ensure the tracks of the hoe or tires of the loader are kept clean and do not introduce contaminants like soil. The loader operator must also take precautions not to dig into the outside edges or penetrate beneath the stockpile where segregation is likely or introduce contaminants from underlying unpaved surfaces. A fourth BMP is stockpile separation, either by physical boundaries or distancing. Many asphalt plants sit on small parcels of land leased from a quarry and often wish to maximize the limited space. However, the chance of cross-contamination of blended aggregates is high without clear separation. The Virginia Department of Transportation outlines the requirements for handling and storing stone in Section 200.05, and Section 211.11 states commingling of aggregates “shall be prevented.” When physical bunkers or separation walls are not being used, stockpiles should be separated to allow the passage of a rubber tire loader. Not only does this distance keep the stockpiles apart, but it also allows the loader operator to work the entire pile and not just one or two faces of the pile. What about processed recycled asphalt pavement (RAP)? In many operations, RAP is separated into fine and coarse sizes. The fine RAP material has a larger percentage of minus #100 sieve material and a higher residual asphalt content. Given the nature of fine RAP, it is more difficult to drain or remove moisture, even when stored on a hard, sloped surface. Therefore, it is a BMP to cover all RAP (both fine and coarse) to minimize the increase in moisture content due to rain. As noted earlier, increases in moisture will increase plant fuel use and decrease overall plant production. To learn more about stockpile management and the various horizontal, stacking conveyors and bunker systems, visit www.vaasphalt.org, under “Asphalt Facts → Research & Case Studies.” BACK TO BASICS BEST PRACTICES: STOCKPILE MANAGEMENT Across millions of tons of mix production in every state, blended aggregates have been proven to make amazingly consistent asphalt at a lower overall cost because production is quicker and more cost-efficient.
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