Microwave method and apparatus for reprocessing pavements

A method of reconditioning nonasphaltic concrete pavement comprising the steps of:

• depositing a layer of asphaltic pavement constituents on said nonasphaltic concrete pavement,
• establishing a microwave energy containment region above said layer including positioning microwave energy emitting waveguide means in spaced apart relationship from said pavement to provide a gap enabling traveling of said waveguide means without direct contact with said layer,
• traveling said containment region along said pavement while concurrently generating heat within the interior of said layer by directing microwave energy into said layer from said containment region while traveling therealong, including distributing said microwave energy substantially uniformly across the width of said layer over which said containment region is traveled,
• suppressing outward propagation of microwave energy from said containment region, and through said gap while traveling along said layer,
• compacting said layer of asphaltic pavement constituents against said concrete pavement while in the heated state.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith while applying microwave energy thereto, said applicator means including a microwave containment structure having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said side portions and said underlying pavement, said applicator means further including a plurality of waveguides positioned to distribute microwave energy substantially uniformly across said underlying area of said pavement and to generate heat within said pavement substantially uniformly thereacross as said vehicle travels along said pavement,
• means carried on said vehicle for releasing microwave energy into said microwave region through said plurality of waveguides to heat said pavement within said underlying area thereof while traveling along said pavement, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, said microwave energy-trapping means being disposed on said vehicle adjacent to said gap in position to receive microwave energy which would escape from said microwave region through said gap beneath said containment structure in the absence of said trapping means.

Apparatus for heating pavement in place at a paved surface comprising:

• a vehicle with support means for enabling travel along said pavement,
• a microwave enclosure supported on said vehicle and formed of electrically conductive material, said microwave enclosure having a top portion spaced above the underlying surface along which said vehicle travels and having side portions extending from said top portion downward toward said underlying surface to define a microwave region bounded by said top portion and said side portions and the underlying area of pavement,
• microwave source means carried on said vehicle for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof,
• microwave energy-trapping means secured to said vehicle for suppressing the release of microwave energy from said region,
• means carried on said vehicle for remixing the constituents of said pavement following passage of said microwave enclosure thereover,
• wherein said vehicle is self-propelled and multiply articulated and has a microwave applicator section carrying said microwave enclosure and said microwave source means and said trapping means and further has a remixing section carrying said remixing means, said microwave applicator section and said remixing section being coupled together by a first pivot means, the vehicle further including a propulsion section situated forward from said microwave applicator section and coupled thereto by second pivot means,
• an engine and a generator driven thereby each being disposed on said propulsion section of said vehicle,
• electrical power conduction means extending from said generator to said microwave applicator section and being flexible at least in the region of said second pivot means, and
• a gas duct extending from said propulsion section to said microwave applicator section and to said remixing section and having means for transmitting hot exhaust from said engine to the pavement underlying said microwave applicator section and to the pavement underlying said remixing section, said gas duct being flexible at least in the region of said first and second pivot means.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith while applying microwave energy thereto, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said side portions and said underlying pavement, said applicator means including a plurality of waveguides for distributing and dispersing microwave energy across said underlying area of said pavement to heat said pavement substantially uniformly thereacross as said vehicle travels along said pavement,
• means carried on said vehicle for releasing microwave energy into said microwave region through said plurality of waveguides to heat said pavement within said underlying area thereof while traveling along said pavement,
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, said microwave energy-trapping means being carried on said vehicle in position to receive microwave energy which would escape from said microwave region through said gap in the absence of said trapping means, wherein said microwave energy-trapping means includes a front microwave trap extending transversely across the front of said microwave region at said gap, a rear microwave trap extending transversely across the back of said microwave region at said gap and a pair of side microwave traps extending along a separate side of said microwave region at said gap, at least one of said side microwave traps being vertically movable relative to said microwave enclosure, and
• actuator means on said vehicle for selectively raising and lowering said one side trap relative to said microwave enclosure.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said portions and said underlying pavement,
• means carried on said vehicle for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, wherein said microwave energy-trapping means is a gap trap comprising a plate of electrically conductive material extending outwardly from said microwave region above said gap and having at least an underside which is spaced above said underlying surface in at least substantially parallel relationship thereto, and wherein said electrically conductive plate is coupled to said microwave applicator means by means for enabling vertical movement of said plate independently of vertical movement of said microwave applicator means and further comprising a plurality of circular rotatable plate-supporting elements journaled on said plate and extending downward to said underlying surface to support said plate at a predetermined height above said underlying surface as said apparatus is traveled therealong.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said portions and said underlying pavement,
• means for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, wherein said microwave energy-trapping means is a gap trap comprising a plate of electrically conductive material extending outwardly from said microwave enclosure above said gap and having at least an underside which is spaced above said underlying surface in at least substantially parallel relationship thereto, and wherein said electrically conductive plate is coupled to said microwave enclosure by means for enabling vertical movement of said plate independently of vertical movement of said microwave enclosure and further including a plurality of circular rotatable plate-supporting elements journaled on said plate and extending downward to said underlying surface to support said plate at a predetermined height above said underlying surface as said apparatus is traveled therealong, wherein each of said rotatable plate-supporting elements is journaled to said plate by resilient means for enabling limited independent vertical movement of each of said plate-supporting elements relative to said plate.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said portions and said underlying pavement,
• means for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, wherein said microwave energy-trapping means is a gap trap comprising a plate of electrically conductive material extending outwardly from said microwave enclosure above said gap and having at least an underside which is spaced above said underlying surface in at least substantially parallel relationship thereto, and wherein said electrically conductive plate is coupled to said microwave enclosure by means for enabling vertical movement of said plate independently of vertical movement of said microwave enclosure and further including a plurality of circular rotatable plate-supporting elements journaled on said plate and extending downward to said underlying surface to support said plate at a predetermined height above said underlying surface as said apparatus is traveled therealong, wherein said rotatable plate-supporting elements are formed at least in part of electrically conductive material and are mutually spaced apart by distances which limit passageways between said elements to less than cutoff dimensions for the frequency of said microwave energy.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith while applying microwave energy thereto, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said side portions and said underlying pavement,
• means carried on said vehicle for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof while traveling along said pavement, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, said microwave energy-trapping means being carried on said vehicle in position to receive microwave energy which would escape from said microwave region through said gap in the absence of said trapping means, wherein said microwave energy-trapping means includes a cavity trap comprising an inverted boxlike structure formed of electrically conductive material and extending along a boundary of said microwave region, the lower edges of said inverted boxlike structure being spaced above said underlying surface.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said side portions and said underlying pavement,
• means for releasing microwave energy into said microwave region to heat said pavement within said underlying area thereof, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, wherein said microwave energy-trapping means includes a cavity trap comprising an inverted boxlike structure formed of electrically conductive material and extending along a boundary of said microwave region, the lower edges of said inverted boxlike structure being spaced above said underlying surface, and a volume of electrically lossy material disposed within said inverted boxlike structure, and wherein said volume of electrically lossy material comprises at least one road wheel of said vehicle, said road wheel being formed at least in part of electrically lossy material and being situated within said cavity trap and constituting an element of said support means for enabling travel of said vehicle along said pavement.

Apparatus for heating pavement in place at a paved surface while traveling therealong comprising:

• a vehicle with support means for enabling travel along said pavement,
• microwave applicator means supported on said vehicle for travel along said pavement therewith while applying microwave energy thereto, said applicator means having an electrically conductive top portion spaced above the underlying surface along which said vehicle travels and having electrically conductive side portions extending from said top portion downward toward said underlying surface to define the upper portion of a traveling microwave region which is bounded by said top portion and said side portions and the underlying area of pavement and by a gap between said side portions and said underlying pavement, said applicator means including a plurality of waveguides for distributing and dispersing microwave energy across said underlying area of said pavement to heat said pavement substantially uniformly thereacross as said vehicle travels along said pavement, wherein each of said plurality of waveguides of said microwave applicator means is supported on said vehicle at said microwave region in spaced apart relationship from said underlying surface along which said vehicle travels and has at least one opening for transmitting microwave energy towards said underlying surface from a zone extending along the side of the waveguide, said waveguides being disposed in parallel relationship,
• means carried on said vehicle for releasing microwave energy into said microwave region through said plurality of waveguides to heat said pavement within said underlying area thereof while traveling along said pavement, including a plurality of microwave energy-generating sources each coupled to a separate one of said waveguides for energizing said waveguides, further including a plurality of parallel panels of electrically conductive material each being situated between a separate adjacent pair of said waveguides in parallel relationship therewith and each extending downward from the region of said waveguides towards said underlying surface, and
• microwave energy-trapping means for suppressing the release of microwave energy through said gap as said vehicle travels along said pavement, said microwave energy-trapping means being carried on said vehicle in position to receive microwave energy which would escape from said microwave region through said gap in the absence of said trapping means.

An asphalt pavement-recycling apparatus comprising:

• a self-propelled towing vehicle,
• at least one electrical generator carried on said towing vehicle,
• at least one fuel-consuming engine carried on said towing vehicle and coupled to said generator to drive said generator,
• at least one microwave energy applicator vehicle coupled to said towing vehicle for travel along said pavement behind said towing vehicle, said microwave applicator vehicle having a microwave energy source receiving electrical power from said generator and further having microwave energy emitting means for directing microwave energy from said source downwardly into the pavement underlying said microwave applicator vehicle said emitting means being spaced above said underlying pavement to enable travel of said apparatus along said pavement while microwave energy is being directed thereto, and
• microwave energy-trapping means on said applicator vehicle for suppressing the outward propagation of microwave energy from said applicator vehicle while traveling along said pavement,
• at least one remixing vehicle coupled to said applicator vehicle and towed thereby, said remixing vehicle carrying at least one means for remixing heated pavement over which said remixing vehicle travels, and
• a flexible cover extending between said microwave applicator vehicle and said remixing vehicle above said pavement.

A pavement-reconditioning vehicle comprising:

• a front vehicle body riding on at least a pair of front road wheels and a second vehicle body riding on at least a pair of second road wheels, said front vehicle body and second vehicle body being coupled together by pivot means which enable pivoting movement of said front vehicle body relative to said second vehicle body about a vertical axis,
• microwave energy-generating means disposed on one of said vehicle bodies,
• microwave energy-emitting means carried on said front vehicle body for directing said microwave energy downwardly into pavement underlying said front vehicle body within a predetermined microwave region at the underside of said front vehicle body, said emitting means being spaced above said pavement to enable travel of said vehicle along said pavement while microwave energy is being directed thereto,
• microwave energy-trapping means disposed on said front vehicle body adjacent said microwave region for suppressing outward propagation of microwave energy therefrom as said vehicle travels along said pavement,
• remixing means carried on said second vehicle body for remixing heated pavement underlying said second vehicle body,
• an electrical generator carried on said second vehicle body, a fuel-consuming engine carried on said second vehicle body and being coupled to said generator to drive said generator,
• electrical conductor means coupling said generator to said microwave energy-generating means,
• an electrical vehicle drive motor disposed on said second vehicle body,
• means mechanically coupling said drive motor to said second road wheels, and means connected between said generator and said vehicle drive motor for transmitting electrical power from said generator to said vehicle drive motor.

A pavement-reconditioning vehicle comprising:

• a front vehicle body riding on at least a pair of front road wheels and a second vehicle body riding on at least a pair of second road wheels, said front vehicle body and second vehicle body being coupled together by pivot means which enable pivoting movement of said front vehicle body relative to said second vehicle body about a vertical axis,
• microwave energy-generating means disposed on one of said vehicle bodies,
• microwave energy-emitting means carried on said front vehicle body for directing said microwave energy downwardly into pavement underlying said front vehicle body within a predetermined microwave region at the underside of said front vehicle body, said emitting means being spaced above said pavement to enable travel of said vehicle along said pavement while microwave energy is being directed thereto,
• microwave energy-trapping means disposed on said front vehicle body adjacent said microwave region for suppressing outward propagation of microwave energy therefrom as said vehicle travels along said pavement,
• remixing means carried on said second vehicle body for remixing heated pavement underlying said second vehicle body,
• an electrical generator carried on said second vehicle body, a fuel-consuming engine carried on said second vehicle body and being coupled to said generator to drive said generator,
• electrical conductor means coupling said generator to said microwave energy-generating means,
• and wherein said remixing means includes a rotary tiller, means carried on said second vehicle body and coupled to said rotary tiller for selectively raising and lowering said rotary tiller, an electrical tiller drive motor mechanically coupled to said tiller and energized by electrical power from said generator.

A vehicle for repairing asphaltic pavement comprising:

• a frame riding on ground-engaging means for enabling travel along said pavement, at least one component of said ground engaging means being a compactor roller journaled to said frame,
• an electrical generator carried on said vehicle,
• an engine carried on said vehicle and driving said generator,
• microwave energy source means carried on said vehicle and coupled to said generator to receive electrical power therefrom,
• microwave-emitting means carried on said vehicle for directing microwave energy from said source into pavement beneath said vehicle, said microwave-emitting means being spaced above said pavement to enable travel of said vehicle along said pavement while said microwave energy is being directed thereto,
• microwave energy-trapping means secured to said vehicle for suppressing outward propagation of microwave energy therefrom while traveling along said pavement,
• remixing means disposed on said vehicle for remixing heated pavement beneath said vehicle,
• an electrical vehicle drive motor,
• rotary drive-transmitting means coupling said vehicle drive motor to said compactor roller to enable said roller to propel said vehicle along said pavement, and
• conductor means connected between said generator and said vehicle drive motor for transmitting electrical power from said generator to said vehicle drive motor.

An asphalt pavement-recycling apparatus comprising:

• a microwave energy applicator vehicle having ground-engaging means for enabling travel along said pavement, said applicator vehicle having a microwave energy-generating source and means for directing microwave energy from said source downwardly into pavement beneath said applicator vehicle,
• at least one motor generator set carried on said apparatus, said motor generator set being of the form producing electrical power and producing hot exhaust gas,
• means connected between said motor generator set and said microwave energy source for transmitting electrical power from said motor generator set to said microwave energy source,
• a paver vehicle disposed behind said microwave applicator vehicle for travel along said pavement behind said applicator vehicle, said paver having a first conveyor means for picking up pavement constituents from the surface in front of said paver, means for depositing said pavement constituents in a layer on the surface over which said paver is traveling, and means for compacting said deposited layer of pavement constituents, and gas conduit means coupled between said motor generator set and said paver vehicle for transmitting at least a portion of said hot exhaust gas from said motor generator set to said pavement constituents within said paver vehicle.

Apparatus for heating pavement in place on a paved surface while traveling along said surface comprising:

• microwave applicator means for establishing an electrically conductive microwave energy barrier above an area of said pavement, said applicator means being spaced apart from said pavement by a gap,
• means coupled to said applicator means for traveling said microwave applicator means along said surface without direct contact of said applicator means with said surface,
• means carried on said apparatus for generating microwave energy,
• means coupled to said generating means for releasing micorwave energy from said generating means into said pavement within the region between said barrier and said area of pavement and for distributing said energy substantially uniformly across a zone of said pavement extending transversely with respect to the direction of travel of said apparatus, and
• microwave trapping means secured to said applicator means for blocking the forward, backward and sideward escape of microwave energy from said region through the gap between said applicator means and said pavement while traveling therealong, said trapping means including at least one electrically conductive microwave reflector element extending outward from said applicator means above said gap in position for reflecting the upwardly directed component of microwave energy, which is propagating through said gap, downwardly for absorption within the underlying surface.

Apparatus for heating pavement in place on a paved surface while traveling along said surface comprising:

• microwave applicator means forming an electrically conductive microwave energy barrier above an area of said pavement,
• means coupled to said applicator means for traveling said microwave applicator means along said surface,
• means carried on said apparatus for generating microwave energy,
• means coupled to said generating means for releasing microwave energy from said generating means into the region between said barrier and said area of pavement,
• means secured to said applicator means for blocking the escape of microwave energy from said region at the interface between said barrier means and said pavement while traveling therealong, wherein said means for blocking the escape of microwave energy comprises an electrically lossy substance disposed in the path of microwave energy which propagates outwardly from said region at said interface.