Abstract: Asphalt roads or the like are repaved by heating and decomposing existing pavement with microwave energy and then remixing and recompacting the constituents of the pavement, the operations being performed at the original location of the old pavement and in some cases without removing the pavement constituents from the roadbed itself. A microwave energy applicator may be traveled along the pavement in front of remixing, grading and compacting equipment or some or all of the equipment may be integrated into a self-propelled vehicle. The vehicle may carry a microwave applicator followed by remixing means such as rotary tillers or the like and grading and compaction devices, and may travel continuously down a road which is reconditioned as the vehicle progresses. Motor generator sets on the vehicle power the microwave sources and the hot exhaust from the motors may be directed to the pavement to supplement the microwave heating and to maintain high temperatures during the additional operations.

Abstract: Pavement (12) is rapidly heated in depth by irradiation with microwave energy accompanied by supplemental surface heating which counteracts an inverted temperature gradient otherwise produced by microwave heating. Energy efficiency is increased by performing the surface heating with thermal energy derived from the exhaust gases of a motor (19) which drives a generator (18) to energize the microwave source (68). An energy applicator (36) simultaneously applies both the microwave energy and hot gas to a selected area of pavement while blocking release of microwave energy in upward and outward directions and is preferably attached to a mobile support (37) through support and positioning linkage (38) which enables shifting of the applicator between localized areas of pavement to be heated.

Abstract: Asphaltic concrete constituents (13) or the like deposited in a windrow (14a) along a surface (12) to be paved are molded into a preliminary narrow layer (14b) of greater height than the final layer (14d) of pavement to be formed on the surface and are then heated by directing microwave energy into the preliminary layer. The heated preliminary layer is then spread out to form the final thinner layer of paving material for smoothing and compaction. Molding means (37) for the preliminary layer and microwave heating means (38) may be carried on a vehicle (16) which travels along the windrow. The vehicle may also carry mixing, spreading and compaction means (39, 92, 89) or some or all of these elements may be on a separate paver vehicle.

Abstract: Portland cement concrete at a roadbed, bridge deck or the like is quickly and deeply heated and dried by directing microwave energy into the concrete and by applying hot gas to the surface. A layer of thermoplastic sealant is applied to the hot concrete followed by an overlayer of asphaltic concrete having a higher softening temperature than the sealant layer. Compaction then produces a composite pavement which is sealed against water intrusion and which can be quickly, easily and economically resealed and resurfaced at a later time using little or no additional paving materials. Resealing and resurfacing is accomplished by deeply reheating all three layers by microwave irradiation followed by recompaction. If cracking and deterioration are severe, the asphaltic concrete layer may be remixed and rescreeding between the reheating and recompaction steps.