Results Interpretation Notes
-
The unpaved road chemical treatment selection tool is
based on charts of expected performance (good, fair, or poor) of
each family of treatments for each objective and the
influence (none, some, or significant) of each of the
input parameters (fines content, plasticity index, traffic, climate and road geometry)
on this expected performance. These
charts were subjectively developed by a panel of
unpaved road practitioners (representing the Federal
Highway Administration, U.S. Forest Service, U.S. Army Corps
of Engineers, Local Technical Assistance Programs, county
government, and academia) and chemical treatment
manufacturers, and are based on past experience and
documented field experiments. The charts can be
viewed in the
UCPRC Guideline.
- A rating for each input parameter is shown in the respective input columns (i.e., first seven columns in the chart).
- A rating of 1 (green cell) implies that the input parameter has little negative influence
on how the chemical treatment will perform.
- A rating of 2 (orange cell) implies that the input parameter could have some influence on
how the chemical treatment will perform and although it does not exclude use of the
treatment, the user should be aware of the potential limitation(s) and should check if
it is relevant to the specific intended application.
- A rating of 3 (red cell) implies that the input parameter could have considerable influence
on how the chemical treatment will perform. It does not exclude use of the treatment, but
practitioners should carefully consider the potential implications before using the treatment
in this particular application.
- The individual ratings are mathematically processed to give an overall rating score. Selections
are ranked according to this score. Selections with equal scores are alphabetically ordered
according to category and sub-category descriptors in the
UCPRC Guideline
and do not imply that
one selection is better than another.
- A rating score of 1.0 (green) indicates that the chemical treatment is worth
consideration and should perform satisfactorily provided that mix design results
indicate good performance, that the road is prepared appropriately, and that the
product is applied according to manufacturer’s instructions and road owner specifications.
- A rating score of between 2.0 and 2.9 (orange) indicates that one or more of the input
parameters (i.e., traffic, climate, material, and/or road geometry) could have an influence
on performance of the treatment and requires additional consideration of the actual
project conditions before selection. Higher scores indicate more than one input parameter
could influence performance of the treatment.
- A rating score of between 3.0 and 3.9 (red) indicates that one or more of the input
parameters could have a significant negative effect on the performance of the treatment
and requires serious consideration before selection. Potential implications should be
discussed with product manufacturers/distributors before a decision is made. If the input
parameter of concern is material related (i.e., plasticity index or fines content), mechanical
stabilization (i.e., addition of fine or coarse material, or clay) can be considered to
correct the problem.
- A rating score of NA implies the treatment is not appropriate for that objective.
- Check the environmental considerations for the selection, whether soil chemistry could influence
performance of the treatment and needs to be checked prior to a final decision being made, and
if the selected treatment can be maintained with conventional unpaved road maintenance techniques. This can
be accomplished by reviewing the "Environmental Considerations and Other Influences"
table
- Provisional specification language for procuring and applying unpaved road chemical treatments is covered in the
UCPRC Guideline.