Civil Engineering Materials
Structural Thermal Insulation Composites
One of NASA’s long-term goals is the establishment of a sustained human presence throughout the solar system. Achieving this goal is dependent on the development of extraterrestrial habitats that can support human life in extreme environments. Extreme temperatures and temperature fluctuations as well as pressure loads are perhaps the greatest challenge to engineers on this research project. This NASA funded research led by Dr. Marc Robinson includes material development and testing as well as finite element modeling to aid in the design and optimization of multifunctional composites for extraterrestrial habitat applications.
Microbes to Control Dust Storms in Asia
Dust storms have been problematic in Mongolia, China, Korea, and Japan for thousands of years. Drs. Sookie and Sangchul Bang have recently obtained funding from Lotte Engineering and Construction of Korea for a project to use microbially induced calcite precipitation (MICP), also known as bacterial cement, in combination with soil fibers to strengthen and prevent the sand particles from becoming airborne. An added benefit of this approach is the production of ammonia by the bacteria. Ammonia acts as a fertilizer to aid vegetative growth and further reduces the potential for dust production. Lotte E&C has a memorandum of agreement with the Mongolian government to build an approximately 1,000 mile long rail line across Mongolia for transporting coal and minerals. This technique holds promise for protecting the rail line from sand storms.
Remediation of Acid Mine Drainage and Mine Tailings with High Carbon Fly Ash
Mining is one of the most important economic activities in South Dakota, contributing $504 million to the state`s gross domestic product (GDP), according to the National Mining Association (NMA) 2010 report. Even though mining is a very important part of the economy in South Dakota, mining activities may cause significant environmental and human health threats due to the discharge of acidic and toxic water associated with the mining practice to the surrounding natural environment. At the same time, the coal power plant industry has experienced a growth in the production of the waste product high carbon fly ashe (HCFAs) in recent years The objective of this study, led by Dr. Bora Cetin, is to assess the feasibility of using HCFA in the remediation of AMD and mine tailings as a sorptive barrier and amendment, respectively.
Environmental Evaluation of Recycled Concrete Aggregates used in Highway Applications
The use of recycled materials (RC) in highway applications is economically feasible and profitable, and reduces energy and virgin natural resource demands on the environment. However, in some cases the environmental impacts associated with RC on groundwater and surface water may exceed the economic benefits such as leaching of metals from these RC aggregates. In addition, the pH of the RC material is very high (pH > 11) and exceeds the EPA Drinking Water Regulations. In this study, Dr. Bora Cetin`s research team is evaluating the environmental impacts of the use of recycled concretes in roadway structures in South Dakota. The leaching of contaminants such as arsenic, chromium, copper, SO42- are being investigated and compared to EPA water quality drinking limits to determine whether the utilization of RCs in such application is environmentally safe.
Concrete-Filled Fiber Reinforced Polymer Tubes for Structural Applications
Concrete-filled fiber reinforced polymer (FRP) tubes for structural building elements represent a novel application of advanced composite materials. Concrete-filled FRP tubes have several advantages over conventional reinforced concrete elements. The FRP tube acts as stay-in-place formwork greatly reducing construction cost and time. In addition the tube serves as external reinforcing eliminating the need for internal steel reinforcing as well as providing concrete confinement and increased resistance to degradation in corrosive environments. This research, led by Dr. Marc Robinson, illustrates that full composite action between the concrete tubes and core could be developed to significantly increase the strength and stiffness of the beams.
Stabilization of Unpaved Roads with Enzymes
Unpaved roads compose a significant majority of roads in South Dakota. These roadways need regular and emergency maintenance, costing South Dakota local and county government a significant amount of money and endangering the safety of local drivers. The mechanical stability of stabilized gravel roadways depends on the type of stabilizers used and the soil and aggregate properties such as fines contents and plasticity index. In this project, Dr. Bora Cetin, Dr. Soonkie Nam and Dr. Lew Christopher are evaluating the mechanical behavior of unpaved roads that are mixed with bio-enzyme chemical agents. This project will provide detailed information on how to more efficiently use bio-enzymes in unpaved road stabilization.
Accuracy of the Optical Flow Techniques on Tensile Strength Tests of Geosynthetic Materials
Determining the deformation response of geosynthetics under load is important in developing an in-depth understanding of the engineering behavior of these materials. Geosynthetics have been instrumented with strain gauges and extensometers. However, these direct contact methods have limitations in fully defining the strain distributions in tested geosynthetics. Image analysis tools may provide more accurate results to define the strain behavior of geosynthetics. In this study, tensile tests were conducted on different types of geosynthetics to determine their strain distributions under loading. Digital images of the geosynthetics specimens were captured during testing and the analyses of time-lapsed images were performed using nine optical flow techniques to define strain distributions within geosynthetics. In this research Dr. Bora Cetin and his research team are analyzing the accuracy and efficiency of these nine optical flow techniques on the determination of the strain distributions of different types of geosynthetics.