This rehabilitation procedure entails pulverizing the old pavement structure, blending in a stabilizing agent, compacting, adding additional material, and resurfacing. This procedure is meant to address deep structural problems ranging to depths as great as 12 in. in the existing structure. This is the practical limit of recycler cut-in and subsequent compaction of the recycled layer. Deeper problems must be addressed by temporary stockpiling, such as windrowing removed material in the right of way (ROW) or otherwise moving existing material off site. Efficiency is improved by using a specialized train to reprocess the existing structure. New base and surfacing is then applied to provide appropriate additional structure, ride quality, skid, weatherproofing, etc. It is imperative that representative samples be taken from the layers to be recycled, preferably in similar gradations as would be produced by the recycling process, in order to evaluate stabilizer type and content in the lab. This may require the use of a small milling machine or a larger continuous flight auger working in one or more representative locations. Additional aggregates may be necessary to improve the gradation if the resulting blend is poor and/or if the depth of desired stabilization is greater than the depth of existing materials above the subgrade. Alternatively, additional passes of the pulverizer can be considered to achieve the desired gradation. Cutting into the existing subgrade should be avoided as this may introduce excessive fines into the blend that may be detrimental to the moisture susceptibility of the recycled layer.

“ offers a sequence of steps for developing a mix design suitable for the recycled layer and is summarized here:

Additional guidelines can be found in Field Performance and Design Recommendations for Full Depth Recycling in Texas.”