Interstate 5 chooses Evotherm WMA

Jun 27, 2011

Earlier this year, Caltrans awarded the Interstate 5 Reconstruction Project near Elk Grove, California to Granite Construction Company (GCC).  The project will reconstruct over 17 miles of Interstate 5 from the San Joaquin and Sacramento County line to the southern limits of the City of Sacramento.  

GCC has a short, 9-hour window to do the work and return the lane back to traffic.  A pre-paving meeting was held that included Caltrans, GCC and Telfer Oil Company.  The group discussed the concern with the time it will take for the mix to cool to the specified 160F, place the next lift, and open the section to traffic. Since Evotherm is easily produced at 250F, adding it to the mix reduces the time for it to cool down and still achieve the necessary densities.

Caltrans required the contractor to incorporate a WMA technology in the various asphalt mixes to improve workability and compaction during the night paving operations. The entire project will utilize over 460,000 tons of asphalt mix with Evotherm warm mix technology.  The mixes specified include 270,000 tons of dense graded mix, 170,000 tons of asphalt rubber gap-graded mix, and 27,000 tons of asphalt rubber open graded friction coarse mix.

Part 1: Slab Replacement
During the week of June 20th, GCC started the slab replacement trial to demonstrate and fine tune slab removal and mix placement strategies. The repair required the removal of the 9” PCC slab and the backfill of the hole in 3 – 3” lifts of dense graded mix. The mix was produced at 255F and was hauled 40 minutes to the jobsite.  The first lift was dumped into the pit and leveled with a skip loader. A vibratory steel drum roller compacted the mix. GCC was able to achieve 94% density with 3-4 passes of the roller.  The final two lifts were placed with a paving machine with the same rolling operations and the same results.  The mix cooled sufficiently to allow GCC to pave subsequent lifts without having to wait for the lift to cool or spray the lift with water.

The slab repair will continue for another 5-6 weeks with mainline paving beginning in the middle to end of July. You can see some of Telfer’s pictures from the job so far here.

Stay tuned for further updates from this large, interstate project!

Author: Brandon MIlar