• Capillary suction model as pipes of different sizes: flow conditions and comparison with experiments 

      Nguyen, Hung Thanh; Jacobsen, Stefan; Melandsø, Frank (Conference object; Konferansebidrag, 2012)
      ABSTRACT Absorption of water in concrete is often described by the simple linear water uptake vs. square-root-of-time law. However, a deviation from this behaviour is frequently seen depending on factors such as initial water content, water/binder ratio and specimen thickness. The deviation increases with thickness (typically from 25 to 100 mm) and is seen even for very dry specimens with ...
    • Evaluating of melting-ice process in a vertical pipe with consideration of net sensible heat 

      Nguyen, Hung Thanh; Gjerløw, Eirik; Huynh, Minh-Thu T. (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-19)
      In ice-melting process, motion of liquid–solid interface is complicated due to moving boundary, which is also called Stefan interface problem. Although the Stefan model has been widely utilized, it frequently overestimates the melting rate. In the present study, the net-sensible-heat of the phases are taken into account as an additional physical effect to the Stefan model for one-phase case and ...
    • Improving Geopolymer Characteristics with Addition of Poly-Vinyl Alcohol (PVA) Fibers 

      Ekaputri, Januarti Jaya; Fujiyama, Chikako; Chijiwa, Nobuhiro; Ho, Tu Dac; Nguyen, Hung Thanh (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-20)
      This paper presents the benefits of PVA fibers in improving the mechanical properties of class F fly-ash-based geopolymer concrete. The activator used in the geopolymer was 8M sodium hydroxide (NaOH) and sodium silicate (Na<sub>2</sub>SiO<sub>3</sub>), with a mass ratio of Na<sub>2</sub>SiO<sub>3</sub> to NaOH varied from 1.5 to 2.5. Cylindrical specimens with a diameter of 100 mm and a height of ...
    • Soil Moisture Variations in Frozen Ground Subjected to Hydronic Heating 

      Sveen, Svein Erik; Nguyen, Hung Thanh; Sørensen, Bjørn Reidar (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-10)
      Full-scale thawing experiments, performed on three types of homogenous, initially frozen soils, were carried out during late winter 2011 and repeated in 2012. An auxiliary heat source (hydronic heating) was employed to initiate and expedite the thawing process. The corresponding phase change, soil temperature increase, and variations in bound and unbound water content were monitored during the ...
    • Thaw Penetration in Frozen Ground Subjected to Hydronic Heating 

      Sveen, Svein Erik; Nguyen, Hung Thanh; Sørensen, Bjørn Reidar (Peer reviewed; Journal article; Tidsskriftsartikkel, 2016-09-22)
      To facilitate excavation and foundation work in seasonally freezing or permafrost regions, the frozen soil must be thawed, either by natural (solar) thawing, or by artificial thawing where an auxiliary heat source is utilized to accelerate the process. In this paper, the process of rapid thawing of frozen ground subject to hydronic heating is studied. In particular, the performance characteristics ...
    • Water and heat transfer in cement based materials 

      Nguyen, Hung Thanh (Doctoral thesis; Doktorgradsavhandling, 2011-06-17)
      For the mass transfer case (the absorption of moisture-water into concrete), the water content in concrete has a significant impact on its mechanical properties. Moisture transport in porous media, for example, plays an important role in the degradation of building materials such as mortars and concrete. LWE ignores the complex pore structure and network, typically found in cement materials. Many ...