Loop 396 in Waco, Texas had been experiencing considerable shoving and permanent deformation at the intersections before it was overlaid with a Superpave mix containing waste toner in August of 1997.
Waste toner, a by-product of the manufacturing process, as well as the spent toner (residue) from copiers and printer cartridges, are dumped in the landfills for lack of a better way of utilizing them. The results of a TxDOT sponsored research study by the University of Texas on waste toner in asphalt persuaded construction of one of the hot mix overlays using binders modified with waste toner. Loop 396 in Waco, Texas (Valley Mills Drive between Waco Drive and Bosque Blvd.) was the selected site, being the first road ever overlaid with toner-modified asphalt. This road has a relatively heavy and slow moving truck load. A 19-mm maximum nominal size coarse Superpave mix was designed for the project. The optimum binder content was 4.3 percent.
Approximately 25 tons of waste toner was shipped to Waco from two toner manufacturing plants and was stored at the hot-mix plant facility. The night-time overlay construction operation of the 2-kilometer 6-lane highway took place during August of 1997. The operation of blending toner and asphalt binder, and placing, and compacting over 5000 tons of the hot mix was conducted successfully. As of today, after two hot summers and a relatively cold winter, the mix is in excellent condition with no signs of distress of any kind.