Research overview
The primary focus of this research group is developing resilient infrastructure materials. We use advanced computational and experimental methods for characterization and performance evaluation to achieve this. Specifically, we develop computational models that simulate the change in chemical composition and its effects on physical properties. We also use a wide range of engineering characterization techniques. The group has expertise in Qualitative and Quantitative X-Ray Diffraction, FTIR, TGA, and SEM-EDS. We use the experimental data to validate and further develop computational models that can simulate the reactions and reliably evaluate the stability of reaction products, contributing to the material's strength.
Computational modeling of stabilized soil materials
Overview:
Chemical stabilizers (e.g., lime, cement, and geopolymers) are frequently used to improve the engineering properties of weak soils. The geochemical reactions between the stabilizer and soil minerals result in the formation of strength-enhancing pozzolanic products such as Calciumsilicate-hydrates (C-S-H). Modeling the complex geochemical reactions resulting in the formation of strength-enhancing products can provide valuable insights for evaluating the effectiveness of a stabilizer. For example, in a moisture-laden environment, C-S-H with a low Ca to Si ratio (Ca/Si~0.33) is more stable as compared to C-S-H with a high Ca to Si ratio (Ca/Si >1). The geochemical model can help determine the soil type and field conditions required to form a durable C-S-H. This project will develop a prototype computational model that can simulate the reaction between a chemical stabilizer and reactive soil minerals at different periods after stabilization. The focus is on evaluating conditions (e.g., pH, the reactivity of soil minerals, and other similar factors) favoring the formation of durable pozzolanic products (e.g., Ca/Si~0.66). The results of this study will also be used to provide recommendations during construction that can help achieve durable, stabilized soil materials
Funding agency: US-Army Engineering and Research Division
Rapid Stabilization of in-situ weak soil
Overview:
Rapid stabilization of expansive soils has significant potential to support infrastructure development, particularly highway pavements. Historically, several studies have attempted to develop a stabilizer that can rapidly convert weak soils to strong soils with little manipulation and straightforward construction protocol. Often, such studies have recommended the use of non-traditional stabilizers that have not been widely implemented. This study aimed to develop and evaluate the use of a mixture composed of conventional stabilizers such as lime, metakaolin, and sodium silicate for rapid strength gain of expansive soils.
Funding agency: Cascadia Lifelines Program, US-Army Engineering and Research Division
Carbon Sequestration into stabilized soil materials
Overview:
Civil engineers frequently use lime to improve the mechanical properties of weak clayey soils. The production of lime is associated with significant CO2 emissions. Sequestering carbon dioxide into the stabilized soil can effectively reduce the carbon footprint of the lime. In the presence of CO2, unreacted lime in the stabilized soil can react with CO2, form stable carbonates (e.g., CaCO3), and trap the CO2. Carbonation occurs due to atmospheric CO2 is a slow and natural process. The use of gaseous CO2 for accelerating carbonation is a popular option. However, this method is not pragmatic for sequestering CO2 in the field. The primary objective of this study is to develop a pragmatic approach for sequestering CO2 into stabilized soil materials. For this purpose, this study investigates different sources of CO2 (gaseous, liquid, and solid sources of CO2) to accelerate the carbonation reaction.
Funding agency: Startup funds