Heah Cheng Yong
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Preferred name
Heah Cheng Yong
Official Name
Heah, Cheng Yong
Alternative Name
Yong, Heah Cheng
Yong, H. C.
Heah, Cheng Yong
Heah, C. Y.
Cheng-Yong, Heah
Cheng Yong, Heah
Main Affiliation
Scopus Author ID
54402789500
Researcher ID
S-7139-2019

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  • Publication
    Cold-pressed fly ash geopolymers: effect of formulation on mechanical and morphological characteristics
    ( 2021)
    Ong Shee-Ween
    ;
    Heah Cheng Yong
    ;
    Lynette Wei Ling Chan
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ho Li Ngee
    ;
    Liew Yun Ming
    ;
    Ooi Wan-En
    ;
    Ng Yong-Sing
    ;
    Nur Ain Jaya
    This research uses low alkali activator content and cold pressing technique for fly ash-based geopolymers formation under room temperature condition. The geopolymers were prepared using four different parameters: fly ash/alkali activator ratio, sodium hydroxide concentration, sodium silicate/sodium hydroxide ratio and pressing force. The results indicated that the compressive strength (114.2 MPa) and flexural strength (29.9 MPa) of geopolymers maximised at a fly ash/alkali activator ratio of 5.5, a 14 M sodium hydroxide concentration, a sodium silicate/sodium hydroxide ratio of 1.5 and a pressing force of 5 tons (pressing stress of 100.0 MPa and 155.7 MPa for compressive and flexural samples, respectively). The degree of reaction (40.1%) enhanced the structure compactness with minimum porosity. The improved mechanical properties confirmed that a high strength pressed geopolymer could be formed at low alkali activator content without the aid of temperature.
  • Publication
    Comparative mechanical and microstructural properties of high calcium fly ash one-part geopolymers activated with Na₂SiO₃-anhydrous and NaAlO₂
    ( 2021)
    Ooi Wan-En
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Ho Li Ngee
    ;
    Foo Kai Loong
    ;
    Ong Shee-Ween
    ;
    Ng Hui-Teng
    ;
    Ng Yong-Sing
    ;
    Nur Ain Jaya
    ;
    Long-Yuan Li
    This paper investigates the effect of varying solid alkali activators on the fresh and hardened properties and microstructural changes of one-part geopolymers (OPGs). Single and binary solid alkali activators were used to activate high calcium fly ash. The alkali activators were either solely sodium metasilicate (Na₂SiO₃) or a combination of sodium aluminate (NaAlO₂) and sodium metasilicate (Na₂SiO₃). The OPG activated with anhydrous Na₂SiO₃ achieved an excellent 28-day compressive strength of 83.6 MPa while OPG activated with NaAlO₂ and Na₂SiO₃ attained a compressive strength of 45.1 MPa. The Na₂SiO₃-activated OPG demonstrated better fluidity than the OPG activated with NaAlO₂ and Na₂SiO₃ due to the thixotropic behaviour caused by the NaAlO₂. The Na₂SiO₃-activated OPG consisted of sodium-calcium aluminium silicate hydrate ((N,C)-A-S-H) gel phase, while the OPG activated with NaAlO₂ and Na₂SiO₃ comprised of the coexistence of sodium aluminium silicate hydrate (N-A-S-H) and calcium aluminium silicate hydrate (C-A-S-H) gel phases. Regardless of the distinctive properties, the OPGs are adequate for building materials applications.