Fully Permeable Pavements.
The UCPRC recently completed the first phase of a study to investigate mechanistic design
methods for fully permeable pavements that can carry truck traffic. Typically, these types
of pavements have only been used in parking lots and on residential streets that do not
carry truck traffic, since most permeable pavement designs cannot carry heavy loads
without deforming. The available design methods are all empirical and generally
recommend against use on roads subjected to truck traffic and even high-speed light
vehicle traffic. Now, the California Department of Transportation (Caltrans) is
interested in investigating the viability and risks of better fully permeable
pavement designs for use in areas that carry heavy truck traffic as a potential
stormwater management best management practice (BMP).
Candidate for fully permeable shoulder retrofit validation site
By definition, a fully permeable pavement is one in which all the layers are
designed to allow water to pass through and into the subgrade. The pavement
structure also serves as a reservoir during storm periods, storing water
in order to limit stormwater runoff and minimize its adverse effects. This
stored water then infiltrates the subgrade and evaporates into the atmosphere.
The UCPRC study included laboratory testing of open-graded surfacings, open-graded
base course materials, and subgrade materials representative of the California
Central Valley; computer performance modeling; and life-cycle analyses. The research
confirmed that fully permeable pavements are unsuited to trafficked lanes on
highways as they do not have the structural capacity of conventional
pavements. However, the results obtained from the analyses indicate that
fully permeable shoulder retrofits to existing highways (see figure) could be
a cost-effective stormwater best management practice alternative. These shoulders
would easily accommodate typical traffic subjected to this part of the
travelled way. They would also be suitable for maintenance yards, parking
lots, and other areas with slow-moving truck traffic.
Deliverables from this research are a preliminary design procedure
and an example set of catalog-type design tables that can be used
to design fully permeable pavement pilot and experimental test
sections in California. The results need to be validated in
controlled experimental test sections and pilot studies
before wider-scale implementation.
Reports on the study can be downloaded
Important Note for Caltrans Users: Prior
to scheduling pavement preservation (preventive maintenance or CAPM) or roadway
rehabilitation work on flexible pavement highway sections, the District Materials
Engineer and/or the Project Manager should review
this spreadsheet to
ensure that the proposed project does not include sections active in
the “Quieter Pavement Research” (QPR) testing program. If the proposed
project is within a QPR test section, please
contact Linus Motumah of the
Caltrans Office of Pavement Design before scheduling the work.
To view maps that show where the sections are located, click the following
(or copy-and-paste it into a new browser window for a slightly larger view).
For more information,
contact John Harvey of the UCPRC or