When the blacktop surface is severely distressed and showing significant cracking, the asphalt pavement has reached the end of its service life.
There are three main options that Minnesota Roadways offers for reconstructing an asphalt pavement; removal and replacement of existing asphalt, reclamation of the existing asphalt, and full depth replacement. The application we recommend will be determined by the overall condition of the asphalt and its underlying materials.
Asphalt Pavement Reconstruction Methods:
Removal and Replacement of Existing Asphalt – Asphalt pavement consists of multiple sizes of aggregate combined with asphalt oil that bonds the aggregate together to create a flexible asphalt pavement. Over the years, weather and traffic will reduce the ability of the oil and aggregate to bond together, creating a brittle asphalt surface. When asphalt has reached the end of its natural life and the underlying gravel base is still structurally sound, the existing blacktop can be removed and replaced with new asphalt pavement. This process involves removing the existing asphalt pavement, which can be taken to a site where it is crushed and reused as a recycled material. After the existing asphalt is removed, the parking lot will be graded to improve drainage and be prepared for the new asphalt parking lot surface. A new asphalt surface will be installed to meet the traffic loads and customer budget for the project site.
Reclamation of Existing Asphalt – In some instances your parking lot may be a candidate for asphalt reclaiming prior to asphalt paving. To reclaim the existing asphalt pavement, equipment will be mobilized onsite to grind and pulverize the existing pavement and gravel base into a uniform recycled base material. This allows us to increase the structural strength of the parking lot by increasing the base thickness. The reclamation process is a cost effective solution compared to full depth pavement replacement. Costs are reduced by utilizing existing materials onsite rather than incurring the expense of new aggregate, transportation of materials, and additional labor.
Full Depth Replacement – When a pavement surface has failed from sub-soil issues or traffic load changes, the pavement foundation will need to be replaced. There are various ways to improve the structural stability of the pavement foundation, and the method will be determined after discussing the customer’s needs and evaluating the failure cause. Full depth replacement consists of excavating the entire area. The unsuitable soils are removed from the site and new gravel base material is installed prior to the new asphalt pavement.
Additional items that should be considered prior to full depth replacement:
- Depth of excavation (typically 12 to 16 inches)
- Possible recycling of existing materials
- Use of ground stabilization fabric (added strength at relatively low cost)
- Drain tile installation (possibly needed to address sub-soil moisture issues)
- Review of traffic loading (cars or heavy trucks)
- Asphalt pavement thickness