The present invention is directed to machines that pave roads and, more particularly, to a self-contained mobile vehicle that is operable to create hot-mix bituminous concrete, asphalt, at the job site.
Roadways are typically formed with either a Portland cement concrete roadway or a roadway formed from bituminous concrete, which is often referred as asphalt. When the roadway surfaces deteriorate, the repair thereto is typically done with an asphalt patch, even the Portland cement concrete road surfaces. Very often, small repairs are done with cold-mix asphalt, which does not have a long life span and deteriorates quickly. Large repairs, even complete re-surfacing of the roadway, are accomplished with large paving machines that receive supplies of hot-mix asphalt from a central mixing plant. Large trucks carry the supply of hot-mix asphalt to the paving machines, which spread the asphalt into a wide swath having a uniform thickness and a smooth uniform surface.
The central asphalt mixing plant is a fixed asset that cannot be easily moved from one location to another. The distance from the job site to the central mixing plant, as well as the ambient temperature, will define the temperature of the hot-mix asphalt at the time of delivery to the job site. Once hot-mix asphalt is cooled, the material hardens and cannot be spread easily or compacted at the job site. The shortness of time during which the bituminous concrete material remains pliable makes the material difficult to be utilized for small repair jobs, or for jobs that are a substantial distance from the central mixing plant. Such problems are particularly difficult to overcome when the ambient temperatures are low, as will be found in the Northern states during the winter months.
In U.S. Pat. No. 3,820,914, granted to Harold M. Zimmerman on Jun. 28, 1974, a self-contained mobile asphalt mixing and applying apparatus was disclosed. This machine depicted in the '914 patent was expensive to manufacture and utilized a mixing drum that was rotated to mix and heat the aggregate for discharge into a mixing auger where the hot liquid bitumen was added to manufacture the bituminous concrete mixture. While this arrangement was successful in mixing small patches of hot-mix bituminous concrete, the volume required for large repairs and/or re-surfacing projects could not be produced. Furthermore, the machine disclosed in the '914 patent was not capable of recycling old bituminous concrete material.
Accordingly, it would be desirable to provide an improved mobile asphalt missing machine that could provide substantial volume of bituminous concrete at job sites.