摘要: |
This report outlines the two accelerated pavement tests completed in Jacksboro, Texas, using the 1/3-scale
Model Mobile Load Simulator (MMLS3). The MMLS3 tests were initially commissioned to investigate the stripping
phenomenon evident under conventional trafficking of the outside lane adjacent to the TxMLS testing in the region.
To achieve this goal, the MMLS3 was used in the field to test a pavement section on the northbound carriageway of
US 281 near Jacksboro. During trafficking of the first MMLS3 test, water flowed over the pavement surface to
accelerate the effects of stripping. Subsequent testing with the MMLS was used to investigate and compare the relative
rutting of the 1/3-scale machine to that of the full-scale TxMLS without the use of water.
In addition to the technical goals described, further development of the prototype MMLS3 was of particular
interest The mean combined operational productivity of the MMLS3 for the wet and dry tests was 79 percent, 13
percent and 8 percent for run, maintenance, and data collection time, respectively. For both the wet and dry tests, data
collection included hourly asphalt layer temperature monitoring, frequent transverse surface profiling. Surface
Analysis of Spectral Waves (SASW) analyses, and relative asphalt surface deformation measurements.
It was found that the temperature gradient of the asphalt concrete layer with water flowing over the surface (the
wet test) ranged from 24 «C to 27 ®C. For the dry test, the gradient ranged from 33 ®C to 38 «C. The SASW modulus
ratios (trafficked versus control sections) determined at the termination of the wet and dry MMLS3 tests were 38
percent and 90 percent, respectively, indicating that the asphalt surfacing (overlay) on the northbound carriageway of
US 281 is potentially susceptible to moisture damage. For this reason, additional wet MMLS3 testing is recommended
on the southbound carriageway of US 281 to ascertain whether this overlay is also susceptible, given that it performed
relatively well under dry conditions.
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