- Public Works
- Road Construction Process
Road Construction Process
The process includes spraying a layer of emulsified asphalt (oil) on the road surface, covering with a layer of 3/8” gravel chips, and rolling the chips into the oil with a rubber-tired roller. This process takes approximately one day for each oiled section. Within a week, the excess gravel chips are swept up. The chip-seal process is a cost-effective measure to lengthen the life of the city streets without having to completely reconstruct them. The city applies a chip-seal treatment on a regular schedule as a significant street maintenance program.
FDR (full depth reclamation)
The road is pre-shaped by the reclaimer and/or motor grader to correct for profile, crown, and contour, according to the plans, before the addition of cement. The existing road is reclaimed to the depth of the plans and, during the first reclaimer pass, water and rock shall be added; pre-shaping can also be accomplished at this time. After completion of the first pass, the road is then shaped with a motor grader and compacted with a steel roller to provide better depth control. Each adjacent pass of the reclaimer overlaps the previous pass by a minimum of six inches. The entire operation of reclaiming the existing road, incorporating add rock, water, and cement can be completed in one pass if, in the opinion of the Engineer, adequate mixing and cement dispersion is achieved.
An asphalt overlay is an additional layer of asphalt that covers imperfections in existing asphalt. Asphalt overlays are commonly applied to driveways, parking lots, and pavement that have minor damage like light cracking, mild deterioration, or slightly sunken areas. The process of overlaying asphalt commonly includes a leveling out of the old asphalt's shape, ensuring a smooth, even surface on which to add additional layers.
After the minor imperfections in the original asphalt have been filled in, butt joints are typically utilized to ensure the base layer remains level. This guarantees the asphalt overlay will match the height of doorways, garage thresholds, roads, sidewalks, and curbs. A special primer is then applied to the surface; this primer acts as the glue that secures the second layer of asphalt to the first. At this point, crushed stone may be necessary to further ensure a level asphalt overlay design. Once the stone has been compressed and graded, the paving begins. Asphalt concrete overlay is poured over the original layer, primer, and crushed stone. The butt joints make certain the asphalt meets the perimeters of the area and remains level. Once it is dried, the overlay has a sleek, smooth appearance that is free of defects.