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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Effect of rubber sludge on the physical and mechanical properties of low calcium fly ash-based geopolymer

2025 , Tee Hoe Woon , Heah Cheng Yong , Ng Qi Hwa , Mohd. Mustafa Al Bakri Abdullah , Jia-Ni Lim , Ong Shee-Ween , O. Wan-En , Hang Yong-Jie

In this research, experimental work has been carried out to check the feasibility of using rubber sludge (RS) to partially replace fly ash (FA) in the production of geopolymer. RS is employed in this study as disposing of RS has led to an issue and is abundant, especially in countries producing rubber products. RS is classified as hazardous waste. Improper awareness on hazardous waste handling can spread a variety of diseases. Therefore, handling of hazardous waste is not easy as competent personnel is required during the collection, transportation, treatment and final disposal. As a result, the cost of disposing the hazardous waste are relatively high. With that, FA incorporated RS geopolymer will able to solve the landfill problems and used it as building materials will save costs, preserve natural resources, and protect the environment from waste impact and hazards. In this study, the physical and mechanical properties were investigated. It was used to replace fly ash at 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%. Water absorption, apparent porosity, bulk density, and compressive strength were tested. The test result shows that 5 wt.% of RS incorporation to fly ash-based geopolymer is optimum as it has 1752 kg/m3 of density, 9.5% of water absorption, 19.2% of apparent porosity, and 49.9 MPa of compressive strength.

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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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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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