Pulverization and recycling is a cost effective alternative for asphalt parking lots that may have areas of base failure or elevations that are too high to allow another pavement overlay such as the situation that is present at most self storage facilities that are 20+ years old.

Process:

Asphalt Pulverization—the economical and efficient way to recycle parking lots in place.

Pulverizing is a recycling process that grinds existing asphalt in place in a single pass and blends it with the underlying materials to form a quality base material.

Pulverizing & Recycling has the following advantages:

• Reuse of existing materials eliminates disposal problems.
• Reduction in costs over hauling off asphalt and importing granular fill or ABC.
• Proven to conserve natural resources.
• Faster project completion times.
• Facilitates correction of pavement profile.
• Reduction of heavy trucks on roadways hauling off broken asphalt and hauling in virgin materials.

In-place mixing. In-place mixing involves the use of portable pulverizing and mixing equipment to blend granular soil or aggregate materials with PSM reagent material and water in pre-determined proportions at the project site. Class F fly ash is usually added in conditioned form, although it may also be added dry. The reagent materials (lime and/or portland cement) are usually added after the fly ash and are most often introduced in a dry form, although they may be added in a slurry form in order to minimize dusting. Water is usually sprayed on the mixture as needed just prior to in-place mixing.

Full depth reclamation. When deteriorated asphalt pavements are recycled in place, a technique known as full-depth reclamation can be used. The flexible pavement and a pre-determined portion of the underlying base material are milled and pulverized to a depth ranging from 150 to 300 mm (6 to 12 inches) or more. The pulverized material is mixed within the reclaiming machine while stabilization reagents (such as lime or portland cement and fly ash) and water are introduced and blended with the pulverized recycled paving aggregate. The reclaimer is then followed by grading, spreading, and compaction equipment working in the same manner and sequence as if plant-mixed PSM material were delivered and placed at the project site.

Spreading. A PSM can be placed with spreader boxes or asphalt laydown machines. Equipment with automated grade control is highly recommended. Layers are normally spread to a thickness of 15 to 30 percent greater than the desired compacted thickness. Maximum lift thickness is 200 to 250 mm (8 to 10 in). Place the second lift on the same day or take appropriate measures to ensure adequate sealing and subsequent bonding of additional lifts.

	The asphalt is pulverized in place and comingled with the underlying base material with either a reclaimer or a milling machine.
	The material is then bladed and graded into place. Additional material is removed with a front end loader and transported to an approved recycling facility. The sub base is proof rolled into place and stabilized to prepare it for asphalt paving.
	The reclaimed material is then paved with usually 2” binder and 1” – 2” of surface.