NJDOT building on fiberless success
Nov 07, 2012
NuStar Energy, Trap Rock Industries, and Schifano Contracting teamed with the New Jersey DOT to use Evotherm warm mix asphalt and eliminate the cellulose fibers in 40,000 tons of stone matrix asphalt (SMA) in the right and left lanes of Route 1 near New Brunswick, NJ. This project built on the success of a warm mix SMA test project in 2009. Running a fiberless SMA mix reduces costs associated with the fibers themselves, a fiber feeding machine, and labor to handle the fibers.
Trap Rock’s plant in Kingston, NJ, supplied the mix for this night-paving job at a production rate of 300 tons per hour. They produced the mix at 290-305 °F and baghouse temperatures hovered around 240 °F. Trucks hauled fiberless, warm SMA mix to the project and hauled RAP material milled from the project back to the plant. This two-way haul can cause buildup of the RAP on the hot truck beds, which may contaminate the SMA mix. No buildup problems were evident during this night’s paving.
Mix temperature behind the screed was 280-300 °F. The mat was smooth and flawless. Paving took place on the fast lane adjacent to the barrier. Water drainage inlets are located at various locations along the barrier. The paving crew performed the handwork around each inlet grate with no more effort than required for a SMA hot mix. Density cores averaged over 95%, well over the NJDOT 93% minimum density for SMA.
The Schifano Construction project superintendent and NJDOT engineers were all very pleased with the Evotherm SMA warm mix. The paving crew also liked the workability of the mix – a good night for all.
Guest author: Ron Corun, NuStar Energy