A Bio-Wicking System to Mitigate Capillary Water in Base Course Webinar
- A Bio-Wicking System to Mitigate Capillary Water in Base Course
- Department of Civil, Architectural, and Environmental Engineering
- Missouri University of Science and Technology
Water within pavement layers is the major cause of pavement deteriorations. High water content results in significant reduction in soil’s resilient behavior and increase in permanent deformation. Conventional drainage systems can only drain gravity water, but not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. This bio-wicking system aims at resolving the potential issues that the original design may encounter: (1) H2Ri ultraviolet degradation, (2) H2Ri mechanical failure, (3) loss of drainage function under high suction, and (4) clogging and salt concentration. Both elemental level and full-scale test results indicated that the bio-wicking system is more effective in draining capillary water within the base courses compared with original design, in which the geotextile is directly exposed to the open air. However, a good drainage condition is required for the bio-wicking system to maintain its drainage efficiency. Accumulation of excess water will result in water re-entering the road embankment. Moreover, grass root and geotextile share the same working mechanism in transporting water. In the proposed bio-wicking system, the relatively smaller channels in the grass roots further ensures water moving from H2Ri geotextile, transporting through the stems of grass, and eventually evapo-transpiring into the air at the leaf-air interfaces. In sum, the bio-wicking system seemed to successfully address the concerns in the preliminary design and is a more efficient system to dehydrate the road embankment under unsaturated conditions.
Dr. Xiong Zhang, P.E., is an associate professor in the Department of Civil, Architectural and Environmental Engineering at the Missouri University of Science and Technology (Missouri S&T). He received his Ph.D. degree in Civil Engineering from Texas A&M University, M.S. and B.S. degrees in Geotechnical Engineering from China Institute of Water Resources and Hydropower Research (IWHR), Beijing, China, and Tongji University, Shanghai, China, respectively. Before he joined in the Missouri S&T, he worked in the University of Alaska Fairbanks and University of Cincinnati for 10 years. Dr. Zhang has been teaching and conducting research in the field of geotechnical engineering since 1992. His studies focus on development of advanced laboratory techniques to rapidly characterize geomaterials, constitutive modeling coupled hydro-mechanical behavior of unsaturated soils, numerical modeling of climate-soil-structure interaction, slope stability analysis, soil stabilization and ground improvement, and frozen ground engineering. He was one of the two speakers of ASCE GeoInstitute Unsaturated Soils Committee Webinar on “Introduction to Constitutive Modeling of Unsaturated Soils.” He just received the 2016 International Innovation Award in Unsaturated Soil Mechanics within the International Society for Soil Mechanics and Geotechnical Engineering.
Dr. Zhang is currently serving as an Associate Editor for Geomechanics and Engineering, An international Journal and committee member of several nationwide technical committees such as TRB AFS20 Committee on Soil and Rock Instrumentation, and ASCE Geo-Institute Pavement Committee and Shallow Foundation Committee. He was secretary general for the 2014 GeoShanghai International Conference and the 2015 International Symposium on Systematic Approaches to Environmental Sustainability in Transportation. He organized several sessions in some international conferences and was an editor of ASCE Geo-Institute Geotechnical Special Publications No.189, 202, and 236.