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

Research Output

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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.

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Effect of silica fume and alumina addition on the mechanical and microstructure of fly ash geopolymer concrete

2021 , Fong Sue Min , Heah Cheng Yong , Liew Yun Ming , Mohd. Mustafa Al Bakri Abdullah , Hasniyati Md Razi , Foo Wah Low , Ng Hui-Teng , Ng Yong-Sing

This paper discussed the effect of the addition of silica fume (2 wt.% and 4 wt.%) and alumina (2 wt.% and 4 wt.%) on the properties of fly ash geopolymer concrete. The fly ash geopolymer concrete achieved the highest 28-day compressive strength with 2 wt.% of silica fume (39 MPa) and 4 wt.% of alumina (41 MPa). The addition of 2 wt.% of silica fume increased the compressive strength by 105% with respect to the reference geopolymer (without additive). On the other hand, the compressive strength surged by 115% with 4 wt.% of alumina compared to the reference geopolymer. The addition of additives improved the compactness of the geopolymer matrix according to the morphology analysis.

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Turning waste into strength enhancing geopolymer composites with Oil Palm Frond Fibers (OPF)

2024-10 , Ng Hui-Teng , Liew Yun Ming , Heah Cheng Yong , Tan Soo Jin , Muhammad Aqil Asyraf Bin Mohd Roslan , Siti Khadijah Binti Zulkepli , Tan You How , Ng Yong-Sing

Geopolymers are alternatives to ordinary Portland cement as construction materials. The increasing demand for sustainable construction materials has driven the utilization of industrial by-products and agricultural waste. The disposal of oil palm frond (OPF) biomass as waste in landfills poses significant environmental challenges, necessitating effective recycling strategies. This study examines the incorporation and feasibility of OPF as a reinforcing fiber in fly ash geopolymer composites, examining its impact on physical and mechanical properties. Various parameters were tested, including fiber content (10–20 wt.%), shapes (shredded and tubular), and lengths (1–3 cm). The geopolymer composites with 10 wt.% shredded oil palm frond and 1-cm tubular oil palm frond fibers enhance the compressive strength by 17% compared to the control sample without oil palm frond. The shredded oil palm frond was particularly effective, enhancing strength performance and achieving better dispersion within the geopolymer matrix. Conversely, increasing the fiber content and length generally resulted in diminished composite strength, attributed to the creation of a more porous structure and weaker fiber-matrix interactions. However, lower fiber additions were shown to decrease porosity and water absorption, highlighting the potential of optimized oil palm frond fiber content and form in improving the environmental and mechanical performance of geopolymer composites. These results support the viability of oil palm frond as a sustainable additive in geopolymers, contributing to waste reduction and material innovation in construction.

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Effect of anisotropic pores on the material properties of metakaolin geopolymer composites incorporated with corrugated fiberboard and rubber

2021 , Nur Ain Jaya , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Low Foo Wah , Ooi Wan-En , Ilham Mukriz Zainal Abidin , Noorhazleena Azaman

This paper compares the compressive strength and thermal conductivity of metakaolin geopolymer (MKG) incorporated with anisotropic and isotropic pores. MKG was prepared by activation with sodium hydroxide and sodium silicate. Corrugated fiberboard and rubber were included to create anisotropy of pores, and they were added in 3, 5, and 7 layers. Hydrogen peroxide and surfactant were added to generate isotropic pores. For geopolymer with corrugated fiberboard (MKG-C) and rubber (MKG-R), compressive test and thermal conductivity measurement were performed in perpendicular and parallel direction to the flat surface of fiberboard and rubber. The result showed that MKG-C and MKG-R exhibited mechanical and insulation anisotropically. The highest compressive strength was achieved in the parallel loading direction while the lowest thermal conductivity was attained in the perpendicular direction. MKG-C possessed better compressive strength of 26.9 MPa loaded in the parallel direction. The compressive strength performance of MKG-C was greater than MKG-R because of the fibrous-like structure, which further contributes to the strength. The thermal conductivity was low (0.15–0.20 W/mK) for both MKG-C and MKG-R. The anisotropy of pores led to high strength retention and improvement of thermal insulating properties. These properties were contrary to geopolymer with isotropic pores (MKG-F), which have excellent thermal insulating properties but low compressive strength to be eligible for structural applications.

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Asas Geopolimer Teori & Amali

2013 , Mohd. Mustafa Al Bakri Abdullah , Rafiza Abd Razak , Zarina Yahya , Kamarudin Hussin , Liew Yun Ming , Heah Cheng Yong , Mohd Izzat, Ahmad

Buku Asas Geopolimer: Teori dan Amali ialah sebuah buku yang membincangkan beberapa perkara asas yang penting mengenai geopolimer. Ia meliputi aspek-aspek seperti; Sejarah geopolimer Pengenalan kepada geopolimer Perbandingan konkrit geopolimer dengan konkrit biasa Bahan mentah dalam geopolimer Tindak balas kimia Kaedah pemprosesan Kualiti konkrit geopolimer Penyelidikan geopolimer masa kini Penulisan buku ini menumpukan kepada teori asas, proses dan pencirian geopolimer yang memberi pengetahuan kepada pembaca mengenai teori dan praktikal berasaskan hasil penyelidikan yang dibuat penyelidik. Tiga perkara utama yang dibincangkan di dalam buku ini ialah bahan mentah (larutan pengaktif alkali), tindak balas kimia yang memainkan peranan dalam proses pengeopolimeran dan pemprosesan geopolimer. Buku Asas Geopolimer: Teori dan Amali ini juga adalah buku pertama yang dihasilkan dalam Bahasa Melayu.

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Publication

Correlation between pore structure, compressive strength and thermal conductivity of porous metakaolin geopolymer

2020 , Nur Ain Jaya , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Kamarudin Hussin

This paper investigates the effect of mixing parameters (that are, alkali concentration, AA ratio, and MK/ AA ratio) on the thermal conductivity of metakaolin geopolymers. The combination effect of foaming agent (H2O2) and surfactant (Tween 80) on the physical properties, compressive strength, and pore characteristic was also elucidated. Results showed that metakaolin geopolymer with maximum compressive strength of 33 MPa, bulk density of 1680 kg/m3 , porosity of 18% and thermal conductivity of 0.40 W/mK were achieved with alkali concentration of 10 M, AA ratio of 1.0 and MK/AA ratio of 0.8. Gradation analysis demonstrated that AA ratio was the strength determining factor. Whilst, thermal conductivity was dependent on the MK/AA ratio. Adding H2O2 and surfactant produced geopolymer foam with acceptable compressive strength (0.4–6 MPa). The geopolymer foam had bulk density of 471–1212 kg/m3 , porosity of 36–86% and thermal conductivity of 0.11–0.30 W/mK. Pore structure, size, and distribution were governed by H2O2 and surfactant dosages that have a great impact on the compressive strength. Narrower pore distribution and smaller pore diameter were achieved when both foaming agent and surfactant were used instead of foaming agent alone. The pore size and distribution varied to a greater extent with varying H2O2 contents. Surfactant illustrated distinct pore stabilizing effect at low H2O2 (<0.75 wt%) which diminished at high H2O2 content. In terms of thermal conductivity, even with increasing porosity at high H2O2 and surfactant content, the thermal conductivity did not show substantial reduction due to the interconnected pores as a result of pore coalescence

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Unveiling physico-mechanical and acoustical characteristics of fly ash geopolymers through the synergistic impact of density and porosity

2024-08-15 , Jia-Ni L. , Liew Yun Ming , Heah Cheng Yong , Tan Wei Hong , Part Wei Ken , Phakkhananan Pakawanit , Tee Hoe-Woon , Hang Yong-Jie , Ong Shee-Ween , Ooi Wan-En

This paper investigates the physico-mechanical and acoustic properties of fly ash geopolymers via casting and pressing methods. The existing research lacks comprehensive insight into the relationship between variations in geopolymer density and their impacts on both physico-mechanical properties and sound insulation and absorption capabilities. Geopolymers, as sustainable construction materials, are pivotal in mitigating noise and providing structural strength. To surpass these limitations and achieve either higher or lower densities in geopolymers, alternative approaches are necessary. Casting (non-foamed and foamed with 1.0, 2.0 and 3.0 foam-to-geopolymer paste ratio) and pressing methods were employed to produce a range of geopolymer densities between 1400 kg/m3 – 2200 kg/m3. The pressing method produced a highly dense geopolymer with an excellent compressive strength of 116 MPa. While the lightest geopolymer produced by adding a foaming agent had a compressive strength of 13 MPa. Good sound transmission loss (66.1 dB) was achieved by highly dense pressed geopolymers. Highly porous geopolymers achieved an excellent sound absorption coefficient of 0.79. The density variation and preparation methods greatly affected the pore size and distribution which subsequently affected the acoustical properties of the geopolymers. Manipulating the density and porosity of the geopolymers is essential for creating spaces with optimal acoustics to meet building codes and noise control regulations.

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Evaluation of flexural properties and characterisation of 10-mm thin geopolymer based on fly ash and ladle furnace slag

2021 , Ng Yong-Sing , Liew Yun Ming , Heah Cheng Yong , Mohd. Mustafa Al Bakri Abdullah , Lynette Wei Ling Chan , Ng Hui-Teng , Ong Shee-Ween , Ooi Wan-En , Hang Yong-Jie

The formulation and flexural properties of thin fly ash geopolymers with thickness of merely 10 mm and replacement of ladle furnace slag to fly ash in thin geopolymer were presented. The formulation was discussed in terms of NaOH molarity, solid aluminosilicates-to-liquid alkali activator (S/L) mass ratio, and alkali activator (Na2SiO3/NaOH) mass ratio. Thin fly ash geopolymers with flexural strength and Young's modulus of 6.2 MPa and 0.14 GPa, respectively, were obtained by using 12 M NaOH, S/L ratio of 2.5 and Na2SiO3/NaOH ratio of 4.0. A high Na2SiO3/NaOH ratio was implemented for thin geopolymer synthesis to produce a more viscous slurry which helped to retain the shape of a thin geopolymer. The incorporation of ladle furnace slag up to 40 wt.% reported an increment of 26% in flexural strength up to 7.8 MPa as compared to pure fly ash geopolymers and the stiffness was increased to 0.19 GPa. Denser microstructure with improved compactness was observed as the ladle furnace slag acted as the filler. New crystalline phases of calcium silicate hydrate (C–S–H) were formed and coexisted with the geopolymer matrix, which consequently enhanced the flexural strength of thin fly ash geopolymer. This proved that the ladle furnace slag has the potential to be utilised in geopolymer synthesis and will enhance the flexural properties of thin geopolymers. The flexural performance of thin geopolymers in this study was considerably good as the thin geopolymers exhibited comparatively similar flexural strengths, but a higher strength/thickness ratio as compared to geopolymers with thickness greater than 40 mm.

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Effect of sodium aluminate on the fresh and hardened properties of fly ash-based one-part geopolymer

2021 , Ooi Wan-En , Liew Yun Ming , Heah Cheng Yong , Ho Li Ngee , Mohd. Mustafa Al Bakri Abdullah , Ong Shee-Ween , Andrei Victor Sandu

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.

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Evaluation of the effect of silica fume on amorphous fly ash geopolymers exposed to elevated temperature

2021 , Ong Huey Li , Liew Yun Ming , Heah Cheng Yong , Ridho Bayuaji , Mohd. Mustafa Al Bakri Abdullah , Foo Kai Loong , Tan Soo Jin , Ng Hui Teng , Marcin Nabiałek , Bartlomiej Jeż , Ng Yong Sing

The properties of amorphous geopolymer with silica fume addition after heat treatment was rarely reported in the geopolymer field. Geopolymer was prepared by mixing fly ash and alkali activator. The silica fume was added in 2% and 4% by weight. The geopolymer samples were cured at room temperature for 28 days before exposed to an elevated temperature up to 1000 °C. The incorporation of 2% silica fume did not cause significant improvement in the compressive strength of unexposed geopolymer. Higher silica fume content of 4% reduced the compressive strength of the unexposed geopolymer. When subjected to elevated temperature, geopolymer with 2% silica fume retained higher compressive strength at 1000 °C. The addition of silica fume in fly ash geopolymer caused a lower degree of shrinkage and expansion, as compared to geopolymer without the addition of silica fume. Crystalline phases of albite and magnetite were formed in the geopolymer at 1000 °C.

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