Seam sealer apparatus and method of sealing seams on an asphalt road

Abstract

Seam sealer for sealing seams in an asphalt paving operation has electric heaters and heats a seam area that includes a narrow strip of previously laid-down asphalt and a narrow strip of the road surface to be paved. A temperature sensor senses temperature of the seam area. A control system adjusts energy level supplied to the heaters, to obtain a pre-determined temperature on the road surface. The pre-determined temperature is close to the temperature of the fresh hot asphalt to be applied. An asphalt paver travels behind the seam sealer and applies fresh hot asphalt to the road surface still to be paved, overlapping it onto the previously laid down asphalt in the seam area. The fresh hot asphalt and the previously laid down asphalt form a molten mass, which is subsequently pressed to a smooth, fused and finished road surface by a road roller.

Description

BACKGROUND INFORMATION[0001]1. Field of the Invention[0002]The invention relates to road paving equipment. More particularly, the invention relates to a method of sealing pavement seams in asphalt paving material and equipment for practicing the same method.[0003]2. Description of the Prior Art[0004]Applying asphalt pavement to roads frequently requires that the asphalt be applied in sections, because the road is too wide to process in a single pass. Thus, first one section of the road width is paved and then the second section. For reasons of simplicity, width sections will be referred to hereinafter as “lanes,” although it is understood that the actual width of the paving step does not have to correspond to a driving lane on the road. The area where one lane of asphalt overlaps another will be referred to as the “seam area.”[0005]Typically, a first lane will be paved along a long stretch of road and the second lane paved at a later time, such as the next day or several days or eve...

AI Technical Summary

Benefits of technology

[0010]The heaters are extendable out from the vehicle, so that they are positioned above the seam area. The heaters may be positioned at varying distances above the seam area. For example, a first heater may be positioned 16 inches above the pavement, a second heater 12 inches, and so on. In this way, the series of heaters applies a graduated heat to the seam area, initially pre-heating it with a low degree of heat, and then applying a progressively higher degree of heat with each subsequent heater. In this way, the road surface in the seam area is heated to the desired temperature in a very controlled manner, thereby eliminating the risk that the previously laid down asphalt in the first lane will combust or chemically break down. Although the progressive application of heat is achieved by setting the heaters to progressively lower distances from the road surface, this may also be achieved by using heaters of increasingly greater output capacities.

[0011]The seam sealer is moved alongside the seam area a pre-determined distance in front of the paving equipment that is applying the fresh hot asphalt, so that an estimated amount of time lapses before the fresh hot asphalt is applied to the second lane. This allows the pre-heated asphalt of the first lane to “cure” or normalize, before the fresh hot asphalt is applied. This curing process allows the heat from the seam sealer to penetrate a certain distance down into the previously laid asphalt of the first lane, so that the asphalt is well heated and not just heated superficially. This heat penetration prior to applying the fresh hot asphalt ensures a better bond, because material from both the previously laid down asphalt and the fresh hot asphalt forms a molten mass and, when pressed together, forms a water-tight, smooth, and seamless bond.

Problems solved by technology

Applying asphalt pavement to roads frequently requires that the asphalt be applied in sections, because the road is too wide to process in a single pass.

A common and well known problem, however, is that, when fresh hot asphalt is laid down on top of asphalt that is at road temperature, the difference in temperature prevents a good bond from forming.

As a result, cracks form along the seam.

Eventually, cracks form in the surface, which results further progressive deterioration of the asphalt surface.

One problem with gas heaters is that it is often difficult to control the heater to prevent too much heat from being applied and from being applied too directly.

As a result, overheating is a common problem and, if overheated to the flash point, the asphalt can burst into flame.

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