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Presentation 1: Transportation and Mitigation of Tire and Road Wear Microparticles in Stormwater Runoff from Highways

By: Dr. Indralil Chowdhury, Washington State University

Abstract: Tire and road wear particles (TRWP) have emerged as significant environmental concerns. In particular, TRWP is a leading source of microplastics in the environment, contributing to non-exhaust vehicular pollution emissions that impact the road corridor ecosystems. The primary objective of this project is to identify the transport and mitigation of tire and road wear microparticles in stormwater runoff from highways. First, this study comprehensively examines the most recent developments regarding these pollutants. The findings reveal that the environmental impact of pollution extends beyond roadside, aerial, waterborne, and soil-settled particles, affecting various species. In our second objective, we investigated the mobility of micro- and nanosized particles carried by stormwater runoff to various aquatic systems. It was observed that micro- and nanoscale tire wear particles are unlikely to agglomerate in environmental water samples. Furthermore, tire particles are likely to exhibit greater stability in water samples in colder regions. Negligible aggregation of micro- and nanoscale tire wear particles was observed in rainwater and wastewater indicating that these emerging pollutants will be highly mobile in rainwater and wastewater. For our final objective, we investigated the mobility and potential removal of micro- and nanoscale tire wear particles from stormwater runoff in the adjacent soil adjacent to the road. Our study demonstrates that during rainfall events (approximately 0.5 cm/min), clean, white quartz sand exhibits limited retention capacity for micro- and nanoscale tire particles. Actual environmental soils however possess a higher electronegativity due to the presence of organic matter. To replicate this effect, we incorporated humic acid (HA) and fulvic acid (FA) into the clean bed filter material. This intervention resulted in further enhancement of the mobility of micro- and nanoscale tire wear particles. In summary, our research underscores the high mobility of micro- and nanoscale tire particles in soil and water. Without appropriate mitigation measures, such as employing modified roadside filter materials, micro- and nanoscale tire wear particles can persist as ubiquitous pollutants in the environment.

Presentation 2: Behavior Assessment of High-Strength Self Consolidation Concrete (HS-SSC) Bridges with Live Load Continuity Through Static and Dynamic Load Testing

By: Dr. John Myers, University of Missouri-Science and Technology

Abstract: Self-consolidating concrete (SCC) and High-Strength Self-consolidating concrete (HS-SCC) has emerged as an alternative to build stronger structures with longer service life. Despite the advantages of using SCC and even HS-SCC, there are some concerns related to its service performance. The effect of a smaller coarse aggregate size and larger paste content is of special interest. It is fundamental to monitor the response to service loads of infrastructure employing SCC and HS-SCC in prestressed concrete members. Bridge A7957 was built employing normal-strength and high-strength self-consolidating concrete in its main supporting members. The diagnostic test protocol implemented in this research included static and dynamic tests and the calibration of refined finite element models simulating the static loads acting on the structure during the first series of diagnostic tests. The main objective of this study centered on (a) presenting a diagnostic test protocol using robust and reliable measurement devices (including noncontact laser technology) to record the bridge’s initial service response; (b) obtaining the initial spans’ performance to evaluate and compare the SCC versus conventional concrete girders’ response when subjected to service loads and (c) as time permits some discussion on dynamic load testing. The initial response of the end spans (similar geometry and target compressive strength, but with girders fabricated using concrete of different rheology) was compared, and the results are presented.