| Summary: | Segmental retaining walls (SRW), typically constructed along highways, have
grown in popularity over the past decade. Manufacturers of SRW blocks have estimated
the service life of a properly constructed wall to be approximately 75 years. However,
there have been reports of SRW systems failing after only five years in service.
Suspected causes of the SRW failures are freeze-thaw damage while exposed to deicing
salts sprayed by snow plows from highways.
The current standard test method used for evaluating the freeze-thaw durability of
SRW blocks has several drawbacks and does not accurately replicate environmental
exposure field conditions. The objective of this research is to develop and assess a new
standard test method for evaluating the freeze-thaw durability of SRW blocks that obtains
reproducible results and offers sufficient information on the freeze-thaw performance for
SRW block manufacturers and state highway agencies (SHAs).
The research completed a preliminary proof of concept test for the new freezethaw
test method developed using small, commercially available SRW blocks to mitigate
potential problems and establish appropriate test parameters. The testing produced
results of freeze-thaw degradation that followed the same modes of failure that has been
discovered during field evaluations.
After the proof of concept test was completed, a series of freeze-thaw tests were
conducted using sets of SHA approved and non-SHA approved SRW blocks. Three different manufacturersâ SRW blocks were evaluated. There was no significant freezethaw
degradation of any of the blocks after 200 freeze-thaw cycles, so for two blocks,
experiments were extended to 400 cycles using a twelve-hour freeze-thaw cycle. The
modification of the test did not result in more rapid deterioration of the SRW blocks.
The researchers found that the freeze-thaw durability test method developed
herein is beneficial for determining the freeze-thaw performance of the lower quality
specified blocks. The test method gives realistic results, which match typical
deterioration modes that are common in field settings, in a timely manner. However, the
test method for testing SHA quality SRW blocks takes longer times and may not be a
reasonable test for such products.
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