Energy conserving paving method and apparatus using microwave heating of materials

A method for paving a strip of surface with paving materials which require heating in which microwave energy is used to generate heat internally within said materials, comprising:

• depositing said materials in a windrow extending along said strip of surface,
• forming successive portions of said materials into a preliminary layer of uniform thickness while traveling along said windrow including reducing energy wastage from unnecessarily deep generation of heat by forming said preliminary layer to be of lesser width and greater thickness than the final layer of paving materials to be formed on said strip of surface, including fixing said height of said preliminary layer to control the depth of penetration of said microwave energy relative to said surface,
• heating said paving materials by microwave irradiation of said preliminary layer while traveling along said strip of surface and while suppressing the escape of microwave energy in upward and outward directions,
• mixing the microwave heated materials of said preliminary layer on said surface while traveling therealong,
• spreading the heated and mixed materials of said preliminary layer laterally while traveling along said strip of surface to form said final layer of paving materials thereon, and
• compacting said final layer of materials on said surface while said materials are still in a heated condition.

A paving materials processing vehicle for heating paving materials which are initially deposited in a windrow extending along a strip of surface to be paved, said vehicle having a vehicle body with ground engaging means enabling movement of said vehicle along said strip of surface, further comprising:

• microwave energy applicator means for directing microwave energy downward into paving materials situated thereunder to heat said materials, including a microwave containment structure having a top wall and sidewalls and materials entrance and exit openings, said containment structure being positioned on said vehicle to receive said windrowed materials through said entrance opening as said vehicle travels along said surface, and further including microwave energy trapping means for blocking the escape of microwave energy in upward and outward directions, said microwave energy applicator means including said containment structure and said trapping means being carried on said vehicle, and
• windrow shaping means for forming said paving materials of said windrow into a preliminary layer of greater height and less width than the final layer of said paving materials to be formed on said strip of surface to be paved, said windrow shaping means being carried on said vehicle in position to intercept said windrow as said vehicle is traveled along said strip of surface and to cause said preliminary layer of paving materials to pass through said microwave containment structure of said microwave energy applicator means as said vehicle travels along said strip of surface.

A paving materials processing vehicle for heating and mixing paving materials which are initially deposited in a windrow extending along a surface to be paved, comprising:

• windrow shaping means for forming said paving materials into a preliminary layer of less width but greater vertical thickness than the final layer of paving materials to be formed on said surface, said shaping means being secured to said vehicle in position to form successive portions of said windrow into said preliminary layer as said vehicle is traveled along said surface,
• an inverted channel structure formed of electrically conductive material and secured to the underside of said vehicle behind said windrow shaping means in position to straddle and pass along said preliminary layer as said vehicle is traveled along said surface, said inverted channel structure having downwardly extending side walls spaced apart a distance corresponding to said width of said preliminary layer and having means for blocking the escape of microwave energy from the region between said side walls other than in a downward direction,
• at least one microwave energy source disposed on said vehicle and waveguide means for directing microwave energy from said source downwardly into said preliminary layer within said region between said side walls,
• means secured to said vehicle for directing hot gas into said region between said side walls to supplement the microwave heating of said paaving materials, and
• means secured to said vehicle for mixing the paving materials of said preliminary layer in place on said surface, said mixing means being disposed at the underside of said vehicle behind said means for directing microwave energy into said preliminary layer.