Method and apparatus for altering an aggregate gradation mixture of an asphalt concrete mixture

摘要

A method and apparatus for altering an aggregate gradation mixture of an asphalt concrete mixture. The apparatus includes a heater for heating a layer of existing roadway materials, a milling and mixing auger for milling the heated layer of existing roadway materials and a hopper and conveyor for providing a predetermined amount of treated new usable aggregates to the milling and auger for mixing with the heated layer of existing roadway materials in order to produce a new asphalt concrete mixture. The auger including a plurality of milling bits extending therearound for receiving the predetermined amount of aggregates and mixing them with the milled layer of existing roadway materials, the milling bits are slanted to direct the aggregates received thereby and milled layer to a center line of the apparatus. A second auger is positioned along the center line of the apparatus and behind the auger for further mixing the new asphalt concrete mixture. A shield plate is adjustably secured to the auger for separating and removing selected unusable aggregates from the material. The hopper is preloaded with the predetermined amount of treated new usable aggregates and the conveyor retrieves the aggregates from the hopper and provides the aggregates to the auger. The new mixture formed by the method and apparatus has the volumetric requirements for a superpave mix in accordance with the design system developed by the Strategic Highway Research Program of 1987.