University of Vermont

Research


Dr. Dewoolkar has had a number of research projects funded by a variety of sponsors. Below is a partial list:

    NEESR Payload: Measurement of the Strength of Liquefied Soil in Physical Models (sponsor: National Science Foundation), in collaboration with Dr. Pedro de Alba, University of New Hampshire.
    GOALI/Collaborative Research: Passive, Diamagnetic Inertial Sensing Integrated with High-Sensitivity Telemetry (sponsor: National Science Foundation), Collaborators: Dr. Jeff Frolik of UVM and Drs. Jing Wang and Tom Weller, University of Southern Florida.
    Reliable and Rapid Prediction of Agent Fate and Transport in Porous Materials (sponsor: Defense Threat Reduction Agency), in collaboration with Drs. Donna Rizzo and Nancy Hayden, UVM.
    Studies to Characterize Interactions between Common Building Materials and Chemical Contaminants (sponsor: Los Alamos National Laboratory), in collaboration with Drs. Donna Rizzo, Nancy Hayden, and Doug Porter, UVM.
    Perdiction and Mitigation of Scour for Vermont Bridges (sponsor: Vermont Agency of Transportation and UVM Transportation Research Center), in collaboration with Drs. Donna Rizzo, Dryver Huston, and Jeff Frolik.
    Research on Pervious Concrete - Mechanical  Properties, Durability, and Field Performance (sponsor: Vermont Agency of Transportation and UVM Transportation Research Center).
    Tracing Sources of Eroded Sediment with Atmospherically-produced 10-Be and Evaluating Quantitative Models of Riverbank Stability (sponsor: Vermont Agency of Natural Resources and UVM Water Center), in collaboration with Dr. Paul Bierman.

Select Research Projects

Contaminant Transport in Building Materials

We are studying contaminant transport through building materials. We are using innovative state-of-the-art techniques such as X-ray tomography, surface permeability mapping and fluorescent confocal microscopy to quantify geomorphic structures of building materials such as sandstone, limestone, concrete and brick. A numerical model will be calibrated using the above data and physical transport experiments.

This study supports an overarching goal of understanding fate and transport of chemical agents in porous materials used in heritage and essential facilities, so appropriate decontamination strategies could be developed. The study is also relevant to building contamination from fires and environmental pollution, which continues to be a serious and expensive problem rendering buildings unusable for long periods of time. This research has been funded by the Los Alamos National Laboratory and Defense Threat Reduction Agency.

  • Hu, L., Savidge, C., Rizzo, D., Hayden, N. Hagadorn, W., and Dewoolkar, M., "Commonly used porous building materials - geomorphic pore structure and fluid transport", Journal of Materials in Civil Engineering, in print.
  • Savidge, C. R., Hu., L. B., Hayden, N. J., Rizzo, D., and Dewoolkar, M. M. (2008), "Variability in surface permeability of porous building substrates and their implications on transport of agents", Chemical and Biological Defense Physical Science and Technology Conference, New Orleans, November.
  • Hu, L. B., Savidge, C. R., Brownell, M., Hayden. N. J.,  Rizzo, D., and Dewoolkar, M. M. (2008), "Prediction of agent transport in porous building materials", Chemical and Biological Defense Physcial Science and Technology Conference, New Orleans, LA, November.

Soil Liquefaction

Some recent experimental investigations and case histories have indicated that liquefaction resistance of sands with fines may actually be smaller than that of clean sands for the same penetration resistance. This observation contradicts the present form of fines corrections in the simplified procedure of liquefaction potential evaluation. Therefore, we are investigating effects of fines on the penetration resistance, shear wave velocity, and liquefaction resistance of sands, and the manner in which they affect the simplified method and fines correction factors currently used in practice. This is done through an extensive experimental program involving cyclic triaxial tests and cone penetration resistance and shear wave velocity measurements in soil specimens in a large calibration chamber.

Another research project on the measurement of the strength of liquefying sand funded under NSF-NEESR-Payload was recently completed.


  • Oka, L. G., Dewoolkar, M. M., and Olson, S. (2012), "Liquefaction assessment of cohesionless soils in the vicinity of large embankments", Soil Dynamics and Earthquake Engineering, 43, 33-44.
  • Anderson, I., Hargy, J., de Alba, P., and Dewoolkar, M. M. (2012), "Measurement of residual strength of liquefied soil in centrifuge models", GeoCongress 2012 Conference, Oakland, CA.
  • Oka, L. G., and Dewoolkar, M. M. (2007), “Effect of existing dams on liquefaction potential analysis of foundation soils”, GeoDenver 2007 New Peaks in Geotechnics, Dynamic Response and Soil Properties, ASCE Geotechnical Special Publication No. 160, Dewoolkar and Koester (eds).

Flow through Unsaturated Porous Media

A moisture retention characteristic curve of soil is of fundamental importance in the analysis of water and solute transport in the vadose zone. This relationship shows clear hysteretic behavior under non-monotonic flow conditions. Most of the existing models attempting to capture this hysteretic behavior were not explicitly derived from first principles and had shortcomings. We developed a thermodynamically consistent framework for modeling the hysteresis of capillarity, which is viewed as an intrinsic dissipation mechanism that can be characterized by a set of internal state variables. A generic evolution equation for internal variables was developed. By virtue of the notion of the bounding surface plasticity, a model of capillary hysteresis capable of predicting all types (primary, secondary, and higher-order) of scanning curves within the boundary loop was developed. The model predictions compared very well with experimental measurements found in the literature. This research was supported by Vermont EPSCoR and published in Water Resources Research. The developed theoretical framework can be extended to describe hydro-mechanical behavior of unsaturated porous media. 

The kinetic effects of soil-moisture retention characteristics can be described by analyzing the acoustic properties (compressional wave velocities and attenuations) of soils. We have designed and built a new apparatus and test procedures capable of measuring the acoustic properties of relatively large unsaturated soil specimens over a full range of saturations; the equipment also simultaneously measures the soil water characteristic curve and the hydraulic conductivity function. Complete data sets have been collected with the new apparatus, and a forward modeling technique has been developed to extract the velocity and attenuation from the measured acoustic waveform. These key measurements are made simultaneously on relatively large soil samples for the first time.

Our results show significant differences in the acoustic properties obtained through wetting versus drying. This phenomenon has been shown to exist in rock samples, and is attributed to the distribution of moisture within the sample, which may also explain the kinetic effects of the soil-moisture retention characteristics. This research has been published in Vadose Zone Journal. Additional work on validation of a theoretical model capable of describing kinetic effects based on acoustic properties of soils is underway. We collaborated on this project with New England Research, Inc., White River Junction, VT, and Prof. Changfu Wei of Institute of Rock and Soil Mechanics, The Chinese Academy of Sciences, China. Parts of this research were funded by VT EPSCoR and VT Space Grant Consortium. 

  • George, L. A., Dewoolkar, M. M., and Znidarcic, D. (2009), “Simultaneous laboratory measurements of acoustic and hydraulic properties of unsaturated soils”, Vadose Zone Journal, 8(3), 633-642, doi: 10.2136/vzj2008.0139.
  • Wei, C. and Dewoolkar, M. M. (2006) “A simple formulation of capillary hysteresis with internal state variables”, Water Resources Research, 42, W07405, 1-16.
  • George, L. A., Dewoolkar, M. M., and Wei, C. (2008) "A device for simultaneous measurement of acoustic and hydraulic properties of unsaturated soils", Proceedings of the First European Conference on Unsaturated Soils, E-UNSAT, Toll G., Augarde, Gallipoli, and Wheeler (eds), July 2-4, 2008, Durham, UK, 97-102.
  • Wei, C. and Dewoolkar, M. M. (2006), “A deductive scheme for modeling hysteresis of capillarity”, Unsaturated Soils 2006, ASCE Geotechnical Special Publication No. 147, Miller, Zapata, Houston & Fredlund (eds), Carefree, Arizona, 2420-2431.
  • Wei, C. and Dewoolkar, M. M. (2006), “A continuum theory of immiscible two-phase flow through porous media with dynamics and hysteresis of capillarity”, Advances in Unsaturated Soil, Seepage, and Environmental Geotechnics, Proceedings of Sessions of GeoShanghai, ASCE Geotechnical Special Publication No. 148, Lu, Hoyos and Reddi (eds), Shanghai, 246-254.

Streambank Erosion and Restoration

Streambank erosion is recognized as one of the most important nonpoint sources of sediment and phosphorus entering streams, rivers, and lakes, and thus one of the largest contributors to the impairment of surface water quality and aquatic habitat. This project was initially funded by the US Geological Survey - UVM Water Center and the Vermont Agency of Natural Resources, and was in collaboration with Prof. Paul Bierman of the Geology Department. We combined many concepts of soil mechanics and geology to gain fundamental understanding of the mechanics of riverbank instability and the source of sediments in streams contributing to increasing phosphorus levels in Lake Champlain. Using in-situ and laboratory testing of streambank soils, determining soil erodibility, continuous remote monitoring of embedded instrumentation, and transient flow and slope stability modeling, we are learning what makes some banks stable and other banks fail over both time and changing river and groundwater conditions. Additionally, a proof-of-concept study determined whether the rare isotope, Beryllium-10 (10-Be), can be used to fingerprint the source of fine-grain, particle reactive sediment transported in the streams and deposited in Lake Champlain. A part of this research was featured on Vermont’s Channel 3 news. This research is currently being continued with funding from VT EPSCoR's Research on Adaptation to Climate Change grant.

 

  • Borg, J. L., Bierman, P. R., Dewoolkar, M. M., Rizzo, D. M., and Rood, D., “Meteoric 10Be adhered to suspended sediment: source and transport dynamics in a large New England watershed”, in revision, Journal of Geophysical Research – Earth Surface.
  • Dewoolkar, M. M., Borg, J., and Bierman, P. (2008), Evaluating Quantitative Models of Riverbank Stability, a report submitted to Vermont Agency of Natural Resources.


Feasibility of Pervious Concrete Pavements for Northern Climates

A pervious pavement system is an environmentally conscious alternative to traditional pavement systems. Northern states have been slow to adopt this kind of technology however, largely because there is little data on the effects of cold weather and wet freezing climate on pavement properties along with a lack of experience base in implementing pervious pavements. The goals of this research are to: (i) evaluate the mechanical and hydraulic behavior of pervious concrete mixes in the laboratory, using local constituents; (ii) quantify the effects of environmental conditions (e.g. freeze-thaw, wear and tear, winter sanding) on the mechanical and hydraulic behavior of laboratory specimens of pervious concrete ; (iii) develop a mix design methodology for an optimal pervious concrete pavement design suitable for northern climates; and (iv) verify findings from the above items using field data (through instrumentation and monitoring) from multiple sites in Vermont. The research is funded by the UVM Transportation Research Center and the Vermont Agency of Transportation. 

  • Suozzo, M. J., and Dewoolkar, M. M., "Long-term field monitoring and evaluation of maintenance practices of pervious concrete pavements in Vermont", Transportation Research Record, in print.
  • McCain, G. N., and Dewoolkar, M. M. (2010), "Porous concrete pavements: mechanical and hydraulic properties", Transportation Research Record, No. 2164, Washington D.C., 66-75.
  • Suozzo, M. J., and Dewoolkar, M. M. (2012), "Long-term field monitoring and evaluation of maintenance practices of porous concrete pavements in Vermont, TRB Annual Meeting, Paper 12-3978 (recommended and accepted for TRR).
  • Berry, B., Suozzo, M. J., Anderson, I. A., and Dewoolkar, M. M. (2012), "Properties of pervious concrete incorporating recycled concrete aggregate", TRB Annual Meeting. paper 12-3994.
  • McCain, G. N. and Dewoolkar, M. M. (2010), “Strength and permeability characteristics of porous concrete pavements”, Transportation Research Board 2009 Annual Meeting, 2010 - publication and presentation, recommended for TRR publication. 
  • McCain, G. N., Suozzo M. J., and Dewoolkar, M. M., (2010) “A laboratory study on the effects of winter surface applications on the hydraulic conductivity of porous concrete pavements”, Transportation Research Board 2009 Annual Meeting, 2010 - publication and poster presentation.

Last modified February 20 2013 01:41 PM

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