Abstract: An improved recycling apparatus for particulate asphaltic concrete comprises a rotatable drum in which the particulate composition is gradually heated between an input end and an output end having a retractable chute extending into a port at the output end for recovering composition of a selected temperature. The chute contains a temperature sensing device, and the apparatus preferably includes a drive means for inserting or retracting the chute, and thermostat means for selecting a product temperature whereby the drive means causes the chute to be extended into the drum to recover the composition of a selected temperature. In another embodiment, the drum includes first, second, and third lifters each extending along different respective lengths of the drum interior to achieve different exposure of the particulate composition to the heating gases in the drum in the respective different drum sections to achieve improved heating and mixing efficiency.

Abstract: An improved process for recycling asphaltic concrete comprises introducing asphaltic concrete particles at one end of an elongated rotating drum while supplying flame and hot gases of combustion to the drum at the opposite end, and introducing virgin aggregate into the drum intermediate the two ends. The asphaltic concrete is heated as it travels along a portion of the length of the drum and is recovered just prior to reaching the position along the drum length at which the aggregate is introduced. The aggregate is heated as it travels toward the end of the drum at which the flame and hot gases are introduced. Heated aggregate may be returned to the drum for further heating, and may be directed to the opposite drum end and mixed with the asphaltic concrete in a section of the drum.

Abstract: An improved recycling apparatus for particulate asphaltic concrete comprises a rotatable drum in which the particulate composition is gradually heated between an input end and an output end having a retractable chute extending into a port at the output end for recovering composition of a selected temperature. The chute contains a temperature sensing device, and the apparatus preferably includes a drive means for inserting or retracting the chute, and thermostat means for selecting a product temperature whereby the drive means causes the chute to be extended into the drum to recover the composition of a selected temperature. In another embodiment, the drum includes first, second, and third lifters each extending along different respective lengths of the drum interior to achieve different exposure of the particulate composition to the heating gases in the drum in the respective different drum sections to achieve improved heating and mixing efficiency.

Abstract: An improved asphaltic concrete recycling apparatus comprises an elongated drum having an open inlet port at a first drum end and a product recovery port adjacent a second and opposite drum end, a burner adjacent the first drum end for introducing hot gases of combustion into the inlet port, and an elongated sleeve extended along the interior of the drum intermediate the first and second ends for directing the hot gases of combustion toward the second drum end. In the preferred embodiment, the first end of the sleeve is located in a portion of the drum where a veil of composition is avoided during drum rotation, and the second sleeve end is located in a drum portion where a curtain or veil of composition is formed.

Abstract: A batch method of producing asphalt-aggregate composition having a temperature of at least about 200.degree. F. and at least about 20% used asphaltic concrete comprises heating solid particles of the used material in a first drum to a temperature of at least about 150.degree. F., separately heating virgin aggregate in a second drum to a temperature of less than about 400.degree. F., and mixing the two materials, preferably with the addition of hot liquid or paving grade asphalt. In a second embodiment, unheated used asphaltic concrete is mixed with heated used asphaltic concrete and heated virgin aggregate.

Abstract: An improved recycling apparatus for particulate asphaltic concrete comprises a rotatable drum in which the particulate composition is gradually heated between an input end and an output end having a retractable chute extending into a port at the output end for recovering composition of a selected temperature. The chute contains a temperature sensing device, and the apparatus preferably includes a drive means for inserting or retracting the chute, and thermostat means for selecting a product temperature whereby the drive means causes the chute to be extended into the drum to recover the composition of a selected temperature. In another embodiment, the drum includes first, second, and third lifters each extending along different respective lengths of the drum interior to achieve different exposure of the particulate composition to the heating gases in the drum in the respective different drum sections to achieve improved heating and mixing efficiency.

Abstract: An improved process for cleaning asphaltic concrete recycle gases comprises introducing a flame into the exhaust gas stream at the opposite drum end that heating gases are introduced.

Abstract: An improved apparatus for recycling asphaltic concrete includes an inclined chute for introducing composition into an open port into which a burner also feeds hot gases of combustion. The apparatus provides for improved continuous processing by feeding composition containing relatively large particle sizes into the open port and recovering heated composition adjacent the opposite drum end.

Abstract: A liquid asphalt composition comprises a mixture of asphalt and a hydrocarbon having over about 55% by weight aromatic content, which mixture is useful for being added to asphalt-aggregate recycle compositions during processing.

Abstract: An apparatus for heating and mixing an asphalt-aggregate composition comprises a drum rotatable about an axis, having a mixing and heating chamber with a restricted port at one end into which a flame and hot gases of combustion are directed and through which exhaust gases concurrently pass to atmosphere. A heating means comprises a burner for directing flame and the hot gases of combustion into the chamber at the restricted port along the drum axis of rotation and which burner is adjustable relative to the port along the drum axis of rotation. A burner assembly includes an air duct having an air entrainment port located away from substantial exposure to the drum exhaust gases. The drum includes a plurality of pegs extending into the drum chamber. Heating is carried out in a rotating drum without forming a veil or curtain of particulate composition through the hot gases of combustion.

Abstract: An improved apparatus for recycling asphaltic concrete includes an inclined chute for introducing composition into an open port into which a burner also feeds hot gases of combustion. The apparatus provides for improved continuous processing by feeding composition containing relatively large particle sizes into the open port and recovering heated composition adjacent the opposite drum end.

Abstract: In a process for producing asphalt-aggregate composition in which used asphaltic concrete is recycled by being heated and mixed in a rotatable drum into which flame and hot gases of combustion are directed, the improvement comprises introducing virgin aggregate in a hot zone of the drum and directly exposing the aggregate to the flame and/or hot gases of combustion, and introducing particles of asphalt-aggregate composition downstream from the hot drum input end, away from direct exposure to the flame and extremely hot gases, in a cooler temperature zone. An improved apparatus includes means for introducing the aggregate at the input drum end for direct exposure to the flame or hottest gases, and means for introducing the used and recycled asphalt-aggregate composition in a cooler drum zone.

Abstract: An apparatus for heating and mixing an asphalt-aggregate composition comprises a drum rotatable about an axis, having a mixing and heating chamber with a restricted port at one end into which a flame and hot gases of combustion are directed and through which exhaust gases simultaneously pass to atmosphere, and a heating means comprising a burner nozzle for directing flame and the hot gases of combustion into the chamber at the restricted port. The nozzle is adjusted relative to the port whereby the volatiles from the asphalt are ignited and burned within the mixing chamber prior to being vented to the atmosphere from the restricted port. Composition may also be introduced and/or removed from the chamber through the restricted port.

Abstract: In a process for recycling asphalt and aggregate containing composition, the improvement comprises separating the composition into a plurality of portions having different particle sizes, ranging from coarse to fine, introducing the particle portions into different mixing and heating drums, one of the drums being for the coarse particle portion, and one or more additional drums for smaller particle portions, and heating the particles in the respective drums with hot gases of combustion at temperatures below that which will burn the asphalt particles in each of the respective drums.

Abstract: In a process for producing asphalt-aggregate compositions in a conventional type dryer-mixer drum in which aggregate is exposed directly to flame and hot gases of combustion while it cascades in the rotating drum, and in which the flame and hot gases of combustion are directed into an input end of the drum, the improvement comprises separating the aggregate into a plurality of different portions or increments each having different particle size ranges, introducing the coarse or larger aggregate particles into the drum and directly exposing them to the flame, its radient heat, hot gases of combustion at the input end, and introducing the finer or smaller aggregate particles downstream from the input end and away from direct exposure to the flame and extremely hot gases in a temperature zone which will avoid overheating the fine particles.

Abstract: In a process for producing asphalt-aggregate composition in which used asphaltic concrete is recycled by being heated and mixed in a rotatable drum into which flame and hot gases of combustion are directed, the improvement comprises introducing virgin aggregate in a hot zone of the drum and directly exposing the aggregate to the flame and/or hot gases of combustion, and introducing particles of asphalt-aggregate composition downstream from the hot drum input end, away from direct exposure to the flame and extremely hot gases, in a cooler temperature zone. An improved apparatus includes means for introducing the aggregate at the input drum end for direct exposure to the flame or hottest gases, and means for introducing the used and recycled asphalt-aggregate composition in a cooler drum zone.

Abstract: The process of the invention comprises directly exposing asphalt-aggregate compositions to hot gases of combustion in which a resulting gaseous mixture comprises mineral particulate matter, nitrogen, carbon dioxide, water vapor, and volatile hydrocarbons resulting from exposure of the asphalt-aggregate composition to the hot gases of combustion, directing the resulting gaseous mixture to a treating chamber and injecting a flame into it. The apparatus according to the invention includes an elongated drum in which asphalt-aggregate composition is exposed directly to flame and/or hot gases of combustion therefrom, and means for exhausting the resulting gaseous mixture to a separate treating chamber.

Abstract: In a process for recycling asphalt and aggregate containing composition, the improvement comprises separating the composition into a plurality of portions having different particle sizes, ranging from coarse to fine, introducing the particle portions into different mixing and heating drums, one of the drums being for the coarse particle portion, and one or more additional drums for smaller particle portions, and heating the particles in the respective drums with hot gases of combustion at temperatures below that which will burn the asphalt particles in each of the respective drums.

Abstract: In recycled asphalt-aggregate compositions prepared by adding a suitable amount of make-up asphalt to pieces of the used composition and heating the mixture in a rotating cylindrical drum by tumbling the composition over heated pipes as it is gradually directed towards an output end of the drum, the improvement comprising adding an amount of petroleum hydrocarbon to achieve a laid down asphalt penetration of between 25 and 300 dmm at 77.degree. F. A further embodiment of the improved process comprises venting a mixture of hydrocarbon gases and moisture vaporized from the hot composition mixture at the output end of the apparatus, condensing the moisture and removing it and returning the hydrocarbon gases to a combustion chamber for providing heat to the apparatus tubes.

Abstract: In a process for producing asphalt-aggregate composition in which used asphaltic concrete is recycled by being heated and mixed in a rotatable drum into which flame and hot gases of combustion are directed, the improvement comprises introducing virgin aggregate in a hot zone of the drum and directly exposing the aggregate to the flame and/or hot gases of combustion, and introducing particles of asphalt-aggregate composition downstream from the hot drum input end, away from direct exposure to the flame and extremely hot gases, in a cooler temperature zone. An improved apparatus includes means for introducing the aggregate at the input drum end for direct exposure to the flame or hot-test gases, and means for introducing the used and recycled asphalt-aggregate composition in a cooler drum zone.