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The focus of this study was to develop and analyze lightweight FRP bridge decks and determine their adequacy under AASHTO's HS25 loading case with minimum stringer spacings of five feet. Two different multicellular decks were designed and tested during this study. Both decks had fiber volume fractions of approximately 54% and weighed 14-15 lb/ft 2 of deck area. Testing was performed to determine both the elastic and failure response at the component level and the elastic response at the system level. Theoretical correlation of stiffness was made via approximate classical lamination theory, and maximum transverse load distribution factors were predicted. In addition, several failure modes were identified and theoretically correlated to obtain applicable limit states based on the strain to failure approach. The study found that local resistance and force transfer across the joints were the areas of potential improvement. The remainder of the study showed adequate performance of the decks.

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The Mississippi corridor of Interstate 269 (I-269) is located in northwest Mississippi and construction of this corridor encompassed approximately 27 miles of new Interstate. This study documents I-269 as a case study of the chemically stabilized soil pavement layers. The evaluation comprises pre-construction activities (material selection, mixture design, pavement design, contract information), construction activities (processes, specifications, as-built quality), and an assessment of three cement stabilized base sections. Detailed assessment included on-site specimen preparation using the plastic mold compaction device (PM Device), core drilling, and subsequent laboratory testing for density, unconfined compressive strength, and elastic modulus. This project was able to document and quantify density variability within current Proctor and nuclear gauge practices to the point where there was noticeable agency and contractor risk. Variability is known to exist in large construction projects, but quantifiable measurements over a large project, as presented in this paper, are more valuable than general expectations for basing future decisions. This paper provides evidence that a construction quality control program where nuclear gauge and Proctor compaction practices are interconnected with mechanical property measurements taken on specimens fabricated with the PM Device is worth considering for implementation. The PM Device fared well for construction, mixture design, and pavement design activities when benchmarked relative to the density, strength, and modulus of the several dozen cores taken and assessed from I-269.

An increased potential for moisture damage and rutting has been the two main problems with warm mixed asphalt (WMA) implementation. The use of high reclaimed asphalt pavement (RAP) contents (25% or more) in WMA may alleviate these problems. At present, susceptibility to the moisture damage and rutting are usually tested for independently; however, these distress mechanisms can be linked for in-service pavements. An enhanced loaded wheel tracking test performed on dry and wet specimens, the PURWheel, is investigated in this paper to evaluate the interaction of traffic and moisture. The PURWheel is also compared with conventional rutting and moisture damage tests. PURWheel results are used to evaluate the performance of 25% and 50% RAP-WMA. Rutting and moisture susceptibility of the high RAP-WMA was comparable with current practice low RAP content hot mixed asphalt.

As transportation infrastructure continues to age, new methods of noncontact sensing should be evaluated and, if found suitable, used for bridge monitoring and structural health assessment. This study highlighted the use of infrasound monitoring, a geophysical technique utilizing acoustics below 20 Hz, as one possible solution for noncontact, nonline-of-sight bridge health monitoring. The study focused on the technique of infrasound for infrastructure monitoring with a detailed case study involving a steel, two-girder bridge in northern California. Infrasound was used to detect natural modes of the structure from a distance of 2.6 km. The frequencies detected infrasonically were validated with data collected by on-structure accelerometers. The noncontact nature of this structural assessment approach has potential to supplement traditional structural assessment techniques as affordable, remote, persistent monitoring of transportation infrastructure. Implications for use of this technology were also discussed alongside specific applications for scour monitoring and postdisaster assessment.

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