Pulverization is an on-grade method of pavement rehabilitation that consists of pulverizing the existing asphalt concrete pavement and a portion of the underlying granular base to a maximum depth of 12 inches, grading and compacting the recycled mixture, and overlaying the recycled surface with a new layer of hot mix asphalt (HMA). Other materials including aggregate base, lime, Portland cement, kiln dust, or fly ash may be added prior to mixing as needed.
Figure 1. Pulverization of aged pavement
Pulverization is best suited for moderate to low volume roadways. During construction, vehicles must traverse an untreated surface, so pulverization requires 24-hour pilot car traffic control. Pulverization can treat most pavement distresses that are not caused by subgrade or drainage problems, but it is most cost effective on surfaces requiring digouts of 20% or more by paving area. The upper portion of the pavement structure is completely reworked. Distresses and surface irregularities treatable using pulverization include:
- Poor ride quality
Pulverization with no stabilization should not be used on pavements with:
- High traffic volumes
- Treated bases
- Numerous shallow utilities
- Poor drainage
- Surrounding urban areas (noise created by the pulverizer may be problematic)
Specifications for Pulverization can be found in the 2018 Standard Specifications Section 30-2 Pulverized Roadbed.
Please forward any questions/comments/suggestions to HQ Office of Asphalt Pavements at CIR@dot.ca.gov.