Author:  Wei, Jianqiang

Publications:

• 2024   Elucidating the role of magnesium in alkali-silica reaction: Performance and mechanisms
• 2023   Functionalization of Metakaolin with Non-Ionic Surfactants: Swelling and Pozzolanic Reactivity
• 2023   Efficacy of functionalized sodium-montmorillonite in mitigating alkali-silica reaction
• 2023   Phase Evolution and Property Development of Alkali-Silica
• 2023   Phase evolution and mechanical-hydroscopic properties of alkali-silica reaction gels modified by magnesium nitrate
• 2023   Metakaolin (MK) has been widely used in modifying cement and designing high-performance concrete, while the role of this alumino-silicate mineral has not been fully exploited due to its low reaction degree, especially at high-volume incorporations. To enhance the pozzolanic reactivity, functionalization of MK particles with two non-ionic surfactants, namely polyoxyethylene (9) nonylphenylether (PONPE9) and toctyl phenoxy poly ethoxyethanol (TX100), are investigated in this study under a hypothesis that the intercalations of the surfactants into MK’s interlayer space can trigger changes in structure and properties. The dry MK particles were mixed with aqueous solutions with two surfactant concentrations to reach two surfactant loadings in MK at its 1.0 and 6.0 cation exchange capacity (CEC). The surfactant uptake behavior of MK and its influence on the hygroscopic swelling, pozzolanic reactivity, and dissolution behavior in simulated cement pore solution were characterized. The results indicate that, compared with TX100, PONPE9 can be absorbed by MK more easily. After functionalization at 1.0 and 6.0 CEC, MK exhibited surfactant mass fractions of 1.85% and 3.81% for TX100, and 1.95% and 5.39% for PONPE9, respectively. The intercalation of surfactants resulted in an up to 28.6% increase in the swell index of MK when absorbing water. A more robust aluminum and silicon dissolution behavior in the simulated cement pore solution was observed from the functionalized MK. Increases in reaction heat and lime consumption capacity were obtained in the MK-lime blends indicating the enhanced pozzolanic reactivity of MK after functionalization and paving a path to enhance the role of MK in future sustainable concrete design.
• 2023   Understanding the role of a novel internal conditioning technique with functionalized montmorillonite in cement hydration kinetics
• 2022   Mitigating alkali-silica reaction through metakaolin-based internal conditioning: New insights into property evolution and mitigation mechanism
• 2021   Short-term mechanical strength prediction of ultra-high performance concrete using noncontact synthetic aperture radar imaging