Virginia Department of Transportation (VDOT) is leading in their use of overlay pavement solutions and composite materials. Through these initiatives, their department is prioritizing the longevity and quality of the materials used in infrastructure throughout the state.
Targeted Overlay Pavement Solutions
Asphalt and concrete have been used as driving surfaces for over a century, but as traffic volumes, axle loads, and tire pressures have increased, so has the demand for high-quality pavement mixtures that can withstand the distress.
Named Innovation of the month in the May 2022 Federal Highway Administration (FHWA) Every Day Counts (EDC) Biweekly Newsletter, The Virginia Department of Transportation (VDOT) has tested targeted overlay pavement solutions (TOPS), an innovation designed to increase sustainability and longevity of the state’s transportation infrastructure.
The goal was to determine the viability of using highly modified asphalt (HiMA) mixtures as a reflective crack mitigation technique or as a tool for increased crack resistance on high-volume facilities in Virginia.
Assessments of HiMA’s constructability, laboratory performance, and initial field performance were recently published by the Virginia Transportation Research Council (VTRC).
VTRC began the study in 2014 with the installation of dense-graded and stone-matrix asphalt HiMA overlays. These were installed over the existing joint concrete pavement and cracked asphalt pavement in several locations in 2015 to reduce reflective cracking.
According to the researchers, the HiMA test sections outperformed conventional polymer-modified asphalt 5 years after construction (2015-2020), regardless of traffic level or pre-existing pavement conditions (PMA). They determined that HiMA increased the life of pavements by 34% when compared to PMA.
Hybrid Composite Beams
The hybrid composite beam (HCB) technology has been introduced as a solution for short and medium span bridge beams. Replacing traditional materials such as concrete and steel, HCB is made up of a concrete tied arch that is encased in a fiber-reinforced polymer shell (FRP).
In 2017, The Virginia Transportation Research Council (VTRC) conducted a study to evaluate HCB girders for use in a skewed bridge project in Colonial Beach, Virginia, as a replacement for the existing bridge that crossed Tides Mill Stream along Route 205.
The bridge, a 40 ft concrete grinder bridge with a 45° skew, serves as a primary connector route for the Colonial Beach community. The primary goals were to gain a better understanding of the system’s behavior, specifically how loads are transmitted, and provide recommendations for how the structure should be inspected and evaluated in the future.
The HCB system is lighter in weight and made of composite materials with a conventionally reinforced concrete deck, allowing multiple materials to be transported on a single truck. This means that smaller cranes can be used during construction, while maintaining the option to reuse existing substructures.
The research recommended that bridge safety inspectors continue to perform evaluations using traditional methods such as visual assessment and sounding to ensure long-term bridge performance.
In addition, it was recommended that other applicable, non-destructive testing methods be identified. These methods would further assist inspectors in accurately assessing the condition of the Tides Mill Stream Bridge over time and set evaluation standards for future structures that contain FPR materials.
With the standards for evaluating the 100-year sustainability estimation continually evolving, it is critical that VTRC and VDOT continue to actively test and report any structural changes.
To read the full study click here.
Sources: FHWA, VDOT