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
    Microstructural Analysis of Fly Ash-based Geopolymers with various Alkali Concentration
    ( 2019-08-14)
    Hui-Teng N.
    ;
    Heah Cheng Yong
    ;
    Yun-Ming L.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Yong-Sing N.
    In the present work, a comparative study on the effect of different concentration of sodium hydroxide (NaOH) on fly ash-based geopolymer was investigated. The geopolymer synthesis by mixing fly ash with alkali activator (a mixture of NaOH and sodium silicate) at solid/liquid ratio of 2.5. The NaOH were used 6M, 8M, 10M, 12M and 14M with constant sodium silicate/NaOH ratio of 2.5. The geopolymers were cured at room temperature (29°C) for 24 hours and 60°C in oven for another 24 hours. The testing and analysis of the fly ash-based geopolymers were performed after 28 days. The adequate Na+ ions and densified microstructure were observed at optimum 8M-NaOH-activated fly ash-based geopolymers.
  • Publication
    Mechanical Properties and Thermal Conductivity of Lightweight Foamed Geopolymer Concretes
    ( 2019-08-14)
    Fatimah Azzahran Abdullah S.
    ;
    Yun-Ming L.
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Heah Cheng Yong
    ;
    Zulkifly K.
    Foamed geopolymer concretes have a better performance in the thermal insulation properties compared to normal geopolymer concretes. In this research, lightweight aggregate geopolymer concretes was incorporated with different percentage of foaming agents (hydrogen peroxide). Compressive strength and thermal conductivity were measured. From results obtained, increased H2O2 contents will decrease the strength of lightweight foamed geopolymer concretes. Lightweight aggregate foamed geopolymer concretes (LWAFGC) with foaming agent content of 0.2wt.% obtained the highest strength of 19.601 MPa. Furthermore, Increased of H2O2 contents also will decrease the thermal conductivity of lightweight foamed geopolymer concretes. Lightweight foamed geopolymer concretes with 2wt.% H2O2 gave the good thermal insulating behavior when the thermal conductivity value recorded the lowest value compare to other wt.% of H2O2 content. The thermal conductivity value of lightweight foamed geopolymer concretes with 2wt.% of H2O2 was 0.072 W/m. K while, the thermal conductivity of other mixtures ranged between 0.077 W/m. K to 0.087 W/m. K., respectively.
  • Publication
    Correlation of Thermal Conductivity Versus Bulk Density, Porosity and Compressive Strength of Metakaolin Geopolymer
    ( 2020-07-09)
    Ain Jaya N.
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    This paper investigates the correlation of thermal conductivity versus bulk density, porosity and compressive strength of metakaolin geopolymer for different mixing parameters (that are, alkali concentration, activator (AA) ratio and metakaolin/activator (MK/AA) ratio). Metakaolin was alkali-activated with NaOH and Na2SiO3 solution to produce geopolymer. Varying NaOH concentration (6M, 8M, 10M, 12 M and 14M), AA ratio (0.4, 0.6, 0.8, 1.0 and 1.2) and MK/AA ratio (0.6, 0.7, 0.8, 0.9 and 1.0) were used to study the effect on bulk density, porosity, compressive strength and thermal conductivity. Result showed that metakaolin geopolymer with maximum compressive strength (33 MPa), bulk density of 1680 kg/m3, porosity of 18% and thermal conductivity of 0.40 W/mK is achieved with alkali concentration of 10M, AA ratio of 1.0 and MK/AA ratio of 0.8. From the gradation analysis of the strength result, AA ratio is the most influential mixing parameter in determining the compressive strength. In contrast, MK/AA ratio significantly affected the thermal conductivity. From the Pearson correlation coefficient, TC had strong relationship with bulk density and porosity and poor relationship with compressive strength.
      1
  • Publication
    Hydrothermal Growth Zinc Oxide Nanorods for pH Sensor Application
    ( 2023-10-01)
    Foo Kai Loong
    ;
    Tan Soo Jin
    ;
    Heah Cheng Yong
    ;
    Subash Chandra Bose Gopinath
    ;
    Liew Yun Ming
    ;
    Uda Hashim
    ;
    Voon Chun Hong
    The aim of this work is to apply synthesized zinc oxide (ZnO) Nanorods using hydrothermal (HTL) growth technique for pH sensor application. The highly crystallite of ZnO Nanorods was obtained by anneal the growth ZnO Nanorods in furnace at 200 °C for 2 hours. Besides that, XRD analysis shows the produced ZnO Nanorods belonged to the (002) plane. Furthermore, Scanning Electron Microscope (SEM) images confirm that the ZnO Nanorods with hexagonal-faceted structural were successfully produced by HTL growth technique. In addition, Ultraviolet–visible (UV-Vis) spectrophotometer analysis shows that the synthesized ZnO belongs to the wide band gap semiconductor material. The growing ZnO Nanorods were then subjected to electrical measurement with various pH levels. The outcome demonstrates that the current rises as the solution changes from acidic to alkaline. Overall, our study shows a relationship between the electrical as well as the structural characteristics of ZnO Nanorods at various pH levels.
      1
  • Publication
    Microwave absorption function on a novel one-part binary geopolymer: Influence of frequency, ageing and mix design
    ( 2024-05-10)
    Yong-Jie H.
    ;
    Heah Cheng Yong
    ;
    Liew Yun Ming
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Yeng-Seng L.
    ;
    Wei-Hao L.
    ;
    Pakawanit P.
    ;
    Shee-Ween O.
    ;
    Hoe-Woon T.
    ;
    Cheng-Hsuan H.
    This paper presents an innovative application of a one-part geopolymer for microwave absorption. The influences of frequency, ageing time and mixing formulations on the mechanical, dielectric, and microwave-absorbing performance of the one-part binary geopolymer using fly ash and ladle furnace slag were investigated. The mixing formulations included alkali activators-to-aluminosilicate sources, sodium metasilicate-to-sodium hydroxide, and water-to-binder ratios. The results demonstrated that the dielectric constant decreased while the dielectric loss and loss tangent increased and remained constant with increasing frequency. The geopolymers have the highest dielectric values at an early age and diminish with ageing time. These resulted in the geopolymers having excellent microwave absorption (50 – 80%) at high-frequency levels and later ages. A higher water content resulted in higher porosity, reducing mechanical strength but enhancing microwave absorption. An optimal water content must be attained to achieve dual mechanical strength and microwave absorption performance.
      1  26
  • Publication
    Comparative mechanical and microstructural properties of high calcium fly ash one-part geopolymers activated with Na2SiO3-anhydrous and NaAlO2
    ( 2021-11-01)
    Ooi Wan-En
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Li L.Y.
    ;
    Ho Li Ngee
    ;
    Foo Kai Loong
    ;
    Ong Shee-Ween
    ;
    Ng Hui-Teng
    ;
    Ng Yong-Sing
    ;
    Nur Ain Jaya
    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.
      2
  • Publication
    Titanium Dioxide Loaded Reduced Graphene Oxide Nanocomposite Film as Counter Electrodes for Dye-Sensitized Solar Cells
    ( 2021-12-21)
    Low F.W.
    ;
    Heah Cheng Yong
    ;
    Liew Yun Ming
    ;
    Md. Aminul Islam
    The demands on conventional fossil fuels are increasing especially developing countries. The growth of population among countries also put a lot of pressure on coil consumption and resulted effect of greenhouse. These phenomena will dramatically increase the global warming and pollutes the nature of earth. For the worse, it would forming some erratic patterns like flood, draughts, wildfire, and so on. Therefore, renewable solar energy is the key target to reduce the fossil fuel consumption, minimize global warming issues, and involuntary minimizes the erratic weather patterns. Dye-sensitized solar cell (DSSCs) is one of the promising prospects for efficient renewable resources. Most of the researchers were tried to use platinum as counter electrode to perform the photovoltaic studies. However, the platinum material will made higher for the entire fabrication cost. Recently, we demonstrated a counter electrode in DSSCs system using the low-cost titanium dioxide (TiO2) decorated reduced graphene oxide (rGO) nanocomposite film. The TiO2-rGO nanocomposite (TiO2-rGO NC) as counter electrode is addressed to minimize electron losses and hence rapid the rate of dye regeneration at ground state. Practically, TiO2-rGO NC synthesized via one-step hydrothermal method. The crystallinity, functional groups, element composition, and morphology of TiO2-rGO NC were comprehensively studied. One-step hydrothermal method revealed that Ti particles (∼60 nm) have capable bonded with rGO thin film, as agreement with XRD and FTIR results. In DSSCs photovoltaic performance, the optimized power conversion energy (PCE) of TiO2-rGO NC as counter electrode achieved a 2.90%, which achieved a desire performance as comparable with rGO and TiO2. In this work, the low-cost TiO2-rGO NC as counter electrode with suppressed recombination in DSSCs is studied.
      1
  • Publication
    Thin fly ash/ ladle furnace slag geopolymer: Effect of elevated temperature exposure on flexural properties and morphological characteristics
    ( 2022-06-15)
    Yong-Sing Ng
    ;
    Liew Yun Ming
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Pakawanit P.
    ;
    Chan L.W.L.
    ;
    Ng Hui-Teng
    ;
    Ong Shee-Ween
    ;
    Ooi Wan-En
    ;
    Hang Yong-Jie
    The flexural properties and thermal performance of 10 mm-thin geopolymers made from fly ash and ladle furnace slag were evaluated before and after exposure to elevated temperatures (300 °C, 600 °C, 900 °C, 1100 °C and 1150 °C). Class F fly ash was mixed with liquid sodium silicate (Na2SiO3) and 12 M sodium hydroxide (NaOH) solution using aluminosilicate/activator ratio of 1:2.5 and Na2SiO3/NaOH ratio of 1:4 to synthesise thin fly ash (FA) geopolymers. 40 wt% of ladle furnace slag was partially replacing fly ash to produce fly ash/slag-based (FAS) geopolymers. Thermal treatment enhanced the flexural strength of thin geopolymers. In comparison to the unexposed specimen, the flexural strength of FA geopolymers at 1150 °C and FAS geopolymers 1100 °C was increased by 161.3% to 16.2 MPa and 208.9% to 24.1 MPa, respectively. A more uniform heating was achieved in thin geopolymers which favoured the phase transformation at high temperatures and contributed to the substantial increase in flexural strength. The joint effect of elevated temperature exposure and the incorporation of ladle furnace slag further improved the flexural strength of thin geopolymers. The calcium-rich slag refined the pore structure and increased the crystallinity of thin geopolymers which aided in high strength development.
      1
  • Publication
    Fly ash-metakaolin blend geopolymers under thermal exposures: Physical and mechanical performances
    ( 2020-11-02)
    Zulkifly K.
    ;
    Heah Cheng Yong
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Kamarudin Hussin
    ;
    Abdullah S.F.A.
    In this paper, an experimental study on the thermo-mechanical properties of fly ash-metakaolin blend geopolymers is presented. Visual observations, density and mass loss and compression test were conducted on geopolymers heated in a furnace at 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C with a heating rate of 10 °C/min and soaking time of 1 hours. Fly ash-metakaolin blend geopolymers possessed excellent strength of 54.7MPa at ambient temperature and degraded 23.4% to 41.9MPa when exposed 200?C. The tested result show that the geopolymer can perform good residual strength (up to 23.2MPa) after 600?C. The strength of geopolymers decreased to 5.8MPa with increasing temperature up to 800?C. Even so, the geopolymers could withstand high temperature and remained intact. The higher mass loss due to the liberation of water from the surface, led to significant strength degradation in fly ash-metakaolin blend geopolymers. However, geopolymer gels exhibited structural stability at 1000°C, since at this temperature it promotes the reaction of the residue fly ash and metakaolin in the geopolymer samples, leading to a strength increase to 9.1MPa Employing blend fly ash and metakaolin as a precursor in the geopolymers helped to minimize the disruption effect caused by high temperature exposures.
      1
  • Publication
    Durability of natural fiber-reinforced alkali-activated composites
    ( 2023-01-01)
    Heah Cheng Yong
    ;
    Liew Yun Ming
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Shee-Ween O.
    ;
    Yong-Jie H.
    ;
    Hui-Teng N.
    ;
    Yong-Sing N.
    ;
    Wan-En O.
    ;
    Jia-Ni L.
    ;
    Hoe-Woon T.
    Durability and sustainability is essential serviceability concern for alkali-activated composites used in construction. The incorporation of natural fibers in alkali-activated materials is beneficial considering its availability, low density, and acceptable mechanical performances. There are two types of natural fibers which are plant and animal fibers. The plant fiber composes of cellulose, hemicellulose, lignin, pectin, and waxy substances. The durability of natural fiber-reinforced alkali-activated composites influences by several factors including type and content of fiber, dispersion and size of fiber, fiber modification, fiber moisture content, fiber alkaline degradation, and fiber mineralization. Besides, this chapter indicates the durability of natural fiber-reinforced alkali-activated composites in terms of crack resistance and toughness, high-temperature resistance, wet/dry cycles, freeze-thaw cycles, chemical resistance, and carbonation resistance.
      1