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Ultrasonic Techniques For Air Void Size Distribution And Property Evaluation In Both Early-Age And Hardened Concrete Samples, Shuaicheng Guo, Qingli Dai, Xiao Sun, Ye Sun, Zhen Liu
Ultrasonic Techniques For Air Void Size Distribution And Property Evaluation In Both Early-Age And Hardened Concrete Samples, Shuaicheng Guo, Qingli Dai, Xiao Sun, Ye Sun, Zhen Liu
Department of Civil, Environmental, and Geospatial Engineering Publications
Entrained air voids can improve the freeze-thaw durability of concrete, and also affect its mechanical and transport properties. Therefore, it is important to measure the air void structure and understand its influence on concrete performance for quality control. This paper aims to measure air void structure evolution at both early-age and hardened stages with the ultrasonic technique, and evaluates its influence on concrete properties. Three samples with different air entrainment agent content were specially prepared. The air void structure was determined with optimized inverse analysis by achieving the minimum error between experimental and theoretical attenuation. The early-age sample measurement showed …
Lowest Matric Potential In Quartz: Metadynamics Evidence, Chao Zhang, Yi Dong, Zhen Liu
Lowest Matric Potential In Quartz: Metadynamics Evidence, Chao Zhang, Yi Dong, Zhen Liu
Department of Civil, Environmental, and Geospatial Engineering Publications
The lowest matric potential is an important soil property characterizing the strength of retaining water molecules and a key parameter in defining a complete soil water retention curve. However, the exact value of the lowest matric potential is still unclear and cannot be measured due to the limitation of current experimental technology. In this study, a general theoretical framework based on metadynamics was proposed to determine the lowest matric potential in quartz minerals. The matric potential was derived from partial volume free energy and can be further calculated by the difference between the adsorption free energy and self‐hydration free energy. …