Students

Mr. Mahedi joined the Sustainable Geotechnical Infrastructure Group (SGIG) at Iowa State University for his PhD in 2016. He has received his M.S. in Civil Engineering from the University of Texas at Arlington (UTA), in 2015 and B.Sc. from Bangladesh University of Engineering and Technology (BUET), Dhaka, Bangladesh in 2013. He finished his PhD in 2019. His research interest includes soil stabilization, in-situ testing and environmental sustainability of transportation infrastructure built with recycled materials.

Articles Published:

• Mahedi, M. and Cetin, B. (2022) "Low Carbon Stabilization and Solidification of Hazardous Wastes, Chapter 23-Beneficial Use of Coal Fly Ash in Geotechnical Infrastructure", pp. 373-394.

• Genc, D., Ashlock, J.C., Cetin, B.,  Cetin, K.S., Mahedi, M., Horton, R., Ceylan, H. (2022) "Monitoring and Modeling of Soil Thermal and Hydraulic Behavior Beneath a Granular-Surfaced Roadway" Advances in Transportation Geotechnics IV, pp. 877-888.

• Mahedi, M., Cetin, B., White, D.J. (2022). Closure to “Cement, Lime, and Fly Ashes in Stabilizing Expansive Soils: Performance Evaluation and Comparison” Journal of Materials in Civil Engineering-ASCE, vol. 33(9), article no. 07021013.

• Mahedi, M., Pinto-Vilar, R., Cetin, B., Ikuma, K., Edil, T.B. (2021) "Sustainable, Low-Cost Waste Materials in Remediating Coal Mine Drain: A Column Study" IFCEE 2021, Dallas, TX, pp. 179-187.

• Genc, D., Ashlock, J.C., Cetin, B.,  Cetin, K.S., Mahedi, M. Horton, R. (2021) "Comparisons of Soil Temperatures and Volumetric Water Contents between the Center and Shoulder Locations of Granular Roadways" Transportation Research Board Annual Meeting Conference Proceedings, Washington DC.

• Mahedi, M., Satvati, S., Cetin, B., Daniels, J.L. (2021). "Chemically Induced Water Repellency and the Freeze–Thaw Durability of Soils", Journal of Cold Regions Engineering-ASCE, vol. 34(3), article no. 04020017.

• Mahedi, M., Cetin, B., and White, D.J. (2020) “Cement, Lime, and Fly Ashes in Stabilizing Expansive Soils: Performance Evaluation and Comparison,” Journal of Materials in Civil Engineering-ASCE, vol. 32(7), article no. 04020177.

• Mahedi, M. and Cetin, B. (2020) "Carbonation Based Leaching Assessment of Recycled Concrete Aggregates", Chemosphere, vol. 250, article no. 126307.

• Mahedi, M., Dayioglu, A.Y., Cetin, B., and Jones, S. (2020) "Remediation of Acid Mine Drainage with Recycled Concrete Aggregates and Fly Ash", Environmental Geotechnics, published online. 

• Genc, D., Ashlock, J.C., Cetin, B.,  Cetin, K.S., Mahedi, M. Horton, R., Ceylan, H.  (2021) "Analysis of In Situ Soil Thermal and Hydraulic Data from a Subgrade Sensor Network under a Granular Roadway" GeoCongress 2020 Minneapolis, MN, pp. 142-151.

• Schreck, S. , Mahedi, M., Cetin, B. (2020) "Leaching Behavior of Metals and Sulfate from Taconite Tailings Used in Pavement Construction"  GeoCongress 2020 Minneapolis, MN.

• Mahedi, M., Cetin, B., Dayioglu, A.Y., (2020) "Effect of Cement Incorporation on the Leaching Characteristics of Elements from Fly Ash and Slag Treated Soils", Journal of Environmental Management, vol. 253, pp. 109720.

• Yang, B., Cetin, B., Zhang, Y.,  Luo, C., Ceylan, H., Horton, R., Kim, S., Mahedi, M. (2019) "Effects of Concrete Grinding Residue (CGR) on Selected Sandy Loam Properties", Journal of Cleaner Production, vol. 240, article no. 118057.

• Mahedi, M. and Cetin, B. (2019) “Leaching of Elements from Cement Activated Fly Ash and Slag Amended Soils", Chemosphere, vol. 235, pp. 565-574.

• Mahedi, M., Cetin, B., and Dayioglu, A.Y. (2019) “Leaching Behavior of Aluminum, Copper, Iron and Zinc from Cement Activated Fly Ash and Slag Stabilized Soils,” Waste Management, vol. 95, pp. 334-355.

• Mahedi, M., Cetin, B., and Cetin, K.S., (2019) “Freeze-Thaw Performance of Phase Change Materials (PCM) Incorporated Pavement Subgrade Soil,” Construction and Building Materials, vol. 202, 449-464.

• Mahedi, M. and Cetin, B. (2019) “Leaching of Elements from Fly Ash and Slag Stabilized Pavement Subgrade Soil”, Proceedings of the 99th Annual Meeting of the Transportation Research Board, Washington, D.C., Extended Abstract

• Mahedi, M, Cetin, B., and White, D.J., (2018) “Performance Evaluation of Cement and Slag Stabilized Expansive Soils”, Journal of Transportation Research Record, vol. 2672(52), pp. 164-173.

Mr. Khan joined ISU in Spring 18 as a PhD Student specializing in Geotechnical Engineering. He received his BSc in Civil Engineering from Bangladesh University of Engineering and Technology. He conducted extensive work to analyze bored pile capacity via use of PLAXIS software. He has been developing numerical models and running simulations pertinent to geotechnical engineering and construction management field. He has developed a decision making asset management tool for the Iowa local agencies to efficiently maintain their granular roadway network. His hobbies are either travelling or learning photography, law or contemporary history.

Articles Published:

• Alam-Khan, S., Cetin, B., Jeong, D., and Ashlock, J.C. (2022). “Gravel Loss Prediction Model Using Beta Regression,” Journal of Transportation Research Record, accepted.

• Alam-Khan, S., Cetin, B., Forman, B.A., Kutay, M.E., Durham, S., Schwartz, C.W. (2022) "Evaluation of Shortwave and Longwave Radiation Models for Mechanistic-Empirical Pavement Analysis", International Journal of Pavement Engineering, vol. 23(1), pp. 3398-3408.

• Alam-Khan, S., Cetin, B., Jeong, H.D., Ashlock, J.C. (2021) "An Overview of Granular Roadway Management Practices", Transportation Research Board Annual Meeting Conference Proceedings, Washington DC, extended abstract.

• Alam-Khan, S., Cetin, B., Jeong, H.D., Ashlock, J.C. (2020) "A System-Level Gravel Loss Prediction Model", GeoCongress 2020, Minneapolis, MN, pp. 192-200.

Mr. Satvati`s research has focused mainly on the non-destructive geotechnical/geophysical field testing, design of unpaved roads, analysis of surface wave propagation and dynamic deflection, and cost analyses of granular roadways built with different material mixtures. He has also been working on stabilization of granular roadways with quarry fines by-products. For this project, he has been investigating the implementation of quarry fines by-products into the granular road surface. His research tries to correlate the plasticity and cementitious characteristics of these particles to determine whether they can bind coarse aggregate materials. In addition, during his M.S. studies he worked on slope stabilization by using planar and tubular geogrids and geotextiles.

Articles Published:

• Satvati, S., Cetin, B., and Ashlock, J.C. (2022). “Development of Prediction Models for Mechanistic Parameters of Granular Roads Using Combined Non-Destructive Tests,” Advances in Transportation Geotechnics IV, pp. 113-126.  

• Mahedi, M., Satvati, S., Cetin, B., Daniels, J.L. (2021). "Chemically Induced Water Repellency and the Freeze–Thaw Durability of Soils", Journal of Cold Regions Engineering-ASCE, vol. 34(3), article no. 04020017.

• Xue, Z., Ashlock, J.C., Cetin, B., Satvati, S., Ceylan, H., Wu, Y., Li, C. (2021) "Freeze-Thaw Performance of Granular Roads Stabilized with Optimized Gradation and Clay Slurry", Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Vol. 1, pp. 139-149.

• Satvati, S., Cetin, B., and Ashlock, J.C. (2021) "Development of Prediction Models for Mechanistic Parameters of Granular Roads Using Combined Non- Destructive Tests", 4th International Conference on Transportation Geotechnics (4th ICTG), Chicago, IL.

• Satvati, S., Cetin, B., and Ashlock, J.C. (2021) "Evaluation of Optimized Compaction Energy for Coarse Aggregates by Gyratory Compactor", IFCEE 2021, Dallas, TX, pp. 390-400.

• Satvati, S., Nahvi, Al., Cetin, B., Ashlock, J.C., Jahren, C.T., and Ceylan, H. (2021) "Performance-Based Economic Analysis to Find the Sustainable Aggregate Option for a Granular Roadway", Transportation Geotechnics, vol. 26, article no. 100410.

• Satvati, S., Cetin, B., Ashlock, J.C., and Li, C. (2020) "Binding Capacity of Quarry Fines for Granular Aggregates", GeoCongress 2020, Minneapolis, MN.

• Wu, Y., Ashlock, J.C., Cetin, B., Satvati, S., Li, C., and Ceylan, H. (2020) "Mechanistic Performance Evaluation of Chemically and Mechanically Stabilized Granular Roadways", GeoCongress 2020, Minneapolis, MN, pp. 591-601.

Mr. Wu is an M.S. student/graduate research assistant specialized in geotechnical engineering at Iowa State University. He has worked on sustainability assessment of granular roads built with recycled materials. He is currently investigating the performance of granular roadways stabilized with 12 different mechanical chemical stabilization methods.

Articles Published:

• Xue, Z., Ashlock, J.C., Cetin, B., Satvati, S., Ceylan, H., Wu, Y., Li, C. (2021) "Freeze-Thaw Performance of Granular Roads Stabilized with Optimized Gradation and Clay Slurry", Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields, Vol. 1, pp. 139-149.

• Wu, Y., Ashlock, J.C., Cetin, B., Satvati, S., Li, C., and Ceylan, H. (2020) "Mechanistic Performance Evaluation of Chemically and Mechanically Stabilized Granular Roadways", GeoCongress 2020, Minneapolis, MN, pp. 591-601.

• Ashlock, J.C., Wu, Y., Cetin, B., Ceylan, H., and Li, C. (2019) “Construction of Chemically and Mechanically Stabilized Test Sections to Reduce Freeze–Thaw Damage of Granular Roads,” Journal of Transportation Research Record, EC-248, pp. 58-63.

Dr. Yang received his M.S. and PhD from the Civil, Construction and Environmental Engineering at Iowa State University. His doctoral research investigated the effects of concrete grinding residue on soil properties and its reuse and recycling potential for soil stabilization purposes. He also investigated the use of bio-based materials in asphalt pavement preservation and pavement subgrade soil stabilization.

Articles Published:

• Luo, C., Wang, Z., Kordbacheh, F., Zhang, Y., Li, S., Cetin, B., Ceylan, H., and Horton, R. (2020) “A Greenhouse Study of Concrete Grinding Residue Influences on Seedling Emergence and Early Growth of Selected Prairie Species,” Water, Air, & Soil Pollution, vol. 231, article no. 253.

• Yang, B., Zhang, Y., Luo, C.,  Cetin, B., Ceylan, H., Kim, S., and Horton, R. (2020) “Effect of Concrete Grinding Residue on Roadside Soil Properties,” Proceedings of the Geocongress, Minneapolis, MN, 11p.

• Luo, C., Wang, Z., Kordbacheh, F., Zhang, Y., Yang, B., Sunghwan, K., Cetin, B., Ceylan, H., and Horton, R. (2019) “The influence of Concrete Grinding Residue (CGR) on Soil Physical Properties and Plant Growth,” Journal of Environmental Quality, vol. 48(6), pp. 1842-1848.

• Yang, B., Cetin, B., Zhang, Y.,  Luo, C., Ceylan, H., Horton, R., Kim, S., Mahedi, M. (2019) "Effects of Concrete Grinding Residue (CGR) on Selected Sandy Loam Properties", Journal of Cleaner Production, vol. 240, article no. 118057.

• Yang, B., Zhang, Y., Cetin, B., Ceylan, H. (2019) “Concrete Grinding Residue – Management Practices and Reuse for Soil Stabilization,” Journal of Transportation Research Record, vol. 2673(11), pp. 748-763.

Dr. Hoang received his PhD from the Department of Civil, Construction, and Environmental Engineering, Iowa State University. He is currently an assistant professor  in the Department of Civil Engineering at the University of Danang – University of Science and Technology, Danang, Vietnam. His research focuses on use of bacteria and enzymes to improve soil strength.

Articles Published:

• Hoang, T.B., Do, H., Alleman, J., Cetin, B., and Dayioglu, A.Y. (2022). “Comparative Evaluation of Freeze and Thaw Effect on Strength of BEICP-stabilized Silty Sands and Cement-and Fly Ash-Stabilized Soils,” Acta Geotechnica, published online.

• Hoang, T., Alleman, J., Cetin, B., and Choi, S. (2020) “Engineering Properties of Bio-Cementation of Coarse- and Fine-Sand Catalyzed By Bacterial Cells and Bacterial Enzyme,” Journal of Materials in Civil Engineering-ASCE, vol. 32(4), article no. 04019380.

• Hoang, T., Alleman, J., Cetin, B., Ikuma, K., and Choi, S. (2018) “Sand and Silty-Sand Soil Bio-Stabilization Using Bacterial Enzyme Induced Calcite Precipitation (BEICP),” Canadian Geotechnical Journal, vol. 56(6), pp.808-822.

Dr. Yang Zhang is a Postdoctoral Research Associate at the Program for Sustainable Pavement Engineering and Research (PROSER) at Iowa State University. His research interest is but not limited to seasonal variations in pavement foundation support conditions and various in situ tests. Dr. Zhang also has research experience on low-volume road rehabilitation and preservation, soil stabilization, forensic evaluation and assessment, concrete material, and road frost action analysis.

Articles Published:

• Zhang, Y., Cetin, B., and Edil, T.B. (2021) “Seasonal Performance Evaluation of Pavement Base Using Recycled Materials,” Sustainability, vol. 13(22), 12714.

• Luo, C., Wang, Z., Kordbacheh, F., Zhang, Y., Li, S., Cetin, B., Ceylan, H., and Horton, R. (2020) “A Greenhouse Study of Concrete Grinding Residue Influences on Seedling Emergence and Early Growth of Selected Prairie Species,” Water, Air, & Soil Pollution, vol. 231, article no. 253.

• Zhang, Y, Daniels, J.L., Cetin, B., and Baucom, I.K. (2020) “Effect of Temperature on pH, Conductivity, and Strength of Lime-Stabilized Soil”, Journal of Materials in Civil Engineering - ASCE, vol. 32(3), article no. 04019380.

• Luo, C., Wang, Z., Kordbacheh, F., Zhang, Y., Yang, B., Sunghwan, K., Cetin, B., Ceylan, H., and Horton, R. (2019) “The influence of Concrete Grinding Residue (CGR) on Soil Physical Properties and Plant Growth,” Journal of Environmental Quality, vol. 48(6), pp. 1842-1848.

• Yang, B., Cetin, B., Zhang, Y.,  Luo, C., Ceylan, H., Horton, R., Kim, S., Mahedi, M. (2019) "Effects of Concrete Grinding Residue (CGR) on Selected Sandy Loam Properties", Journal of Cleaner Production, vol. 240, article no. 118057.

• Yang, B., Zhang, Y., Cetin, B., Ceylan, H. (2019) “Concrete Grinding Residue – Management Practices and Reuse for Soil Stabilization,” Journal of Transportation Research Record, vol. 2673(11), pp. 748-763.

Research Title:Improving the Engineering Properties of Expansive Belle Fourche Clay by Using Chemical Additives

Expansive soil problems are frequently observed in the northern plains (North Dakota and South Dakota, Montana, Wyoming and Colorado) and southwest states (Texas and Arizona) of the United States and billions of dollars are spent each year for repairing structures (Wyoming Office of Homeland Security 2014). Repair costs of the structural damages due to the expansive soil problems are usually much more expensive than the cost to stabilize the soil prior to construction. Different techniques have been used to mitigate the volumetric instability of soils such as changing the applied compaction energy and moisture content, pre-wetting expansive soils before the construction, building moisture barriers and waterproof membrane. In addition to those methods, another widely used technique is mixing the soil with chemical additives such as cement, fly ash and lime. The main objective of this study is to improve the engineering properties (strength and swelling pressure) of Belle Fourche clay, which is obtained from Belle Fourche Shale that is one of the most common expansive shales in South Dakota (Brandner 2009), to provide adequate foundation for pavements. To achieve this goal, the locally available Belle Fourche Shale was mixed with 3 different chemical additives: class C fly ash, class F fly ash and lime. A number of tests were conducted on Belle Fourche clay as well as mixtures of Belle Fourche clay with class C and class F fly ashes and lime. Swelling pressure and unconfined compression strength of the soil and mixtures were measured. In addition, the impacts of curing period, chemical additive type and content on the engineering properties of Belle Fourche clay were investigated. Lastly, the effect of freeze and thaw (F-T) cycles on the swelling pressure and strength of specimens was studied.

Articles Published:

• Dayioglu, M., Cetin, B., and Nam, S. (2017) “Stabilization of Expansive Belle Fourche Shale Clay with Different Chemical Additives,” Applied Clay Science, vol. 146, pp. 56-69.

Research Title: Performance of Different Climate Data Sources in Mechanistic-Empirical Pavement Distress Analyses

Accuracy and reliability of the input data are critical in the MEPDG approach for predicting pavement performance. Climatic factors affect the behavior of all layers in the pavement system and have a direct influence on several deterioration processes including thermal cracking, frost heave and thaw weakening, rutting, (Mills et al. 2007; Johanneck and Khazanovic, 2010; Meagher et al. 2012). It is known that climate is a crucial parameter that must be taken into account during the design of pavements. However, there have been concerns about the reliability and accuracy of the climate data provided with the MEPDG software.

To address this need, our research team used a new and spatially comprehensive weather data source for MEPDG software in addition to data available from ground-based weather stations. NASA’s Modern-Era Retrospective Analysis for Research and Applications (MERRA) product can be used to provide hourly climatic data for MEPDG analysis. MERRA is a global climate reanalysis product that combines computed model fields with ground-, ocean-, atmospheric-, and satellite-based observations. The purpose of this research project was to identify the best climate sources to use in MEPDG pavement performance predictions. The results of this study showed that MERRA is as reliable as ground-based weather stations for critical weather data. In addition, MERRA has several advantages over currently available ground-based weather sources: denser, more uniform, and broader spatial coverage; better temporal frequency and continuity; excellent data consistency and quality.

Articles Published:

• Cetin, B., Forman, B.A., Schwartz, C.W., and Ruppelt, B. (2018) “Performance of Different Climate Data Sources in Mechanistic-Empirical Pavement Distress Analyses,” Journal of Transportation Engineering, Part B: Pavements, vol. 144 (1), article no. 04017023. –The most downloaded paper of the journal in May 2018.

Research Title: Evaluation of Potential Applications of Recycled Concrete Aggregate and Fly Ash for Acid Mine Drainage Remediation

When feasible it is of best practice to prevent the formation of acid mine drainage (AMD) using source control measures such as sealing or flooding of underground mines, solidification of mine tailings, and disposal of mine wastes in sealed waste heaps.  Unfortunately, these treatment methods can be extremely costly, requiring continuous chemical input and large volumes of virgin material, such as lime (CaO) and limestone (CaCO3).  In an effort to reduce the high costs of AMD treatment, interest has developed in various applications of low-cost waste products, such as fly ash and recycled concrete aggregate (RCA), for AMD remediation.  Both RCA and fly ash are highly alkaline, exhibiting unique binding properties that could make them effective alternatives to costly, lime and limestone treatment.

The objective of this study, through laboratory testing and analysis, was to evaluate the low-cost construction waste products, recycled concrete aggregate and fly ash, as remediation materials for AMD treatment.  Column Leach Tests (CLTs) were conducted to assess the impact of fly ash and RCA on pH, electrical conductivity, alkalinity, oxidation reduction potential (Eh); and concentrations of Ca, Cu, Cr, Fe, Mg, Mn, and Zn in AMD. Following the CLTs, additional analytical methods were conducted to better understand the treatment process on a molecular basis.  X-ray fluorescence spectroscopy (XRF) was used to evaluate the impact of oxide, alkalinity, and unburned carbon content of the remediation materials on their capacity to sorb metals from AMD.  In addition, Geochemist’s Workbench was employed to create a geochemical model to better understand changes in aqueous speciation of AMD caused by treatment.

Articles Published:

• Jones, S.N. and Cetin, B. (2017) “Evaluation of Waste Materials for Acid Mine Drainage Remediation,” FUEL, vol. 188, pp. 294-309.

• Jones, S.N. and Cetin, B. (2017) “Remediation of Acid Mine Drainages with Recycled Concrete Aggregates,” Geotechnical Special Publication, American Society of Civil Engineers, vol. 276, pp. 450-458, Orlando, FL.

Research Title: Environmental Suitability Recycled Concrete Aggregates Used in Highway Base Layers

The use of recycle materials in pavement systems in lieu of natural aggregates has been an interest for some time. Crushed waste concrete, termed recycled concrete aggregate (RCA), is  considered as an alternative material to be used in roadway construction.  Using recycled materials increases the sustainability of the project because the environmental and economic impacts associated from mining and processing of natural aggregates are minimized and/or eliminated.  This also diverts concrete waste streams from landfills, saving valuable space. Recycled concrete aggregate use is widespread in many countries but it is shown that RCA materials have potential to leach metals. The objective of this study was to understand the impact of atmospheric exposure time, reaction time, L:S ratio, particle size and pH on the leaching behavior of the selected metals (Ca, Cr, Cu, Fe and Zn) and to identify the leaching controlling mechanisms of metals, and also to compare the concentration levels obtained from the Batch Water Leach tests (WLT) against the concentration levels obtained from Synthetic Precipitation Leaching Procedure tests (SPLPs), and Toxicity Leaching Procedure tests (TCLP), which were selected to simulate the exposure of RCA to potentially more acidic water environment.

Articles Published:

• Bestgen, J.O., Cetin, B., and Tanyu, B.F. (2016) “Effects of Extraction Methods and Factors on Leaching of Metals from Recycled Concrete Aggregates,” Environmental Science and Pollution Research, vol. 23(13), pp. 12983-13002.

• Bestgen, J.O., Hatipoglu, M., Cetin, B., and Aydilek, A.H. (2016) “Mechanical and Environmental Suitability of Recycled Concrete Aggregate as a Highway Base Material,” Journal of Materials in Civil Engineering - ASCE, vol. 28(9), article no. 04016067.

• Lewis (Bestgen), J., Cetin, B., and Aydilek, A.H. (2015) “Effect of pH on the Leaching of Elements from Highway Base Layers Built with Recycled Concrete Aggregates”, San Antonio, TX, 10 p. (CD-Rom).