Now showing 1 - 10 of 93
  • Publication
    Ladle furnace slag replacement on the flexural strength of thin fly ash geopolymer
    ( 2020)
    Ng YONG-SING
    ;
    ; ;
    Ng HUI-TENG
    ;
    Ridho BAYUAJI
    This article reports the investigation on the effect of ladle furnace slag replacement on the flexural strength of thin fly ash-based geopolymer. The thin fly ash/slag geopolymers were prepared with the replacement of various percentages of ladle furnace slag (0%, 10%, 20%, 30% and 40%) into fly ash geopolymers with dimension of 160 mm × 40 mm × 10 mm. The thin geopolymerwas synthesised using 12M sodium hydroxide (NaOH) solution with solid-to-liquid (S/L) ratio of 2.5 and Na2SiO3 /NaOH ratio of 4.0. The curing temperature and time of samples were 60°C and 6 hours respectively. The mechanical properties of thin geopolymers was revealed using flexural test after 28 days. Several characterisation tools have been used including Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to correlate the flexural properties with the microstructure and phases of fly ash/slag geopolymers. Results obtained reported that a positive effect on flexural strength was observed with the increasing amount of slag. The thin fly ash geopolymers replaced with 40% of ladle furnace slag showed the highest flexural strength of 7.8 MPa. The rich CaO content in ladle furnace slag boosted the C-S-H gels formation which increased the flexural strength of thin geopolymers.
  • Publication
    Turning waste into strength enhancing geopolymer composites with Oil Palm Frond Fibers (OPF)
    ( 2024-10)
    Ng Hui-Teng
    ;
    ; ; ;
    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.
  • Publication
    Diverse material based geopolymer towards heavy metals removal : a review
    ( 2023)
    Pilomeena Arokiasamy
    ;
    ; ;
    Monower Sadique
    ;
    ; ;
    Mohd Remy Rozainy Mohd Arif Zainol
    ;
    Che Mohd Ruzaidi Ghazali
    Metakaolin is a commonly used aluminosilicate material for the synthesis of geopolymer based adsorbent. However, it presents characteristics that restrict its uses such as weak rheological properties brought on by the plate-like structure, processing challenges, high water demand and quick hydration reaction. Industrial waste, on the other hand, contains a variety of components and is a potential source of aluminosilicate material. Geopolymer adsorbent synthesized by utilizing industrial waste contains a wide range of elements that offer better ion-exchangeability and increase active sites on the surface of geopolymer. However, limited studies focused on the synthesized of geopolymer based adsorbent by utilizing industrial waste for heavy metal adsorption in wastewater treatment. Therefore, this paper reviews on the raw materials used in the synthesis of geopolymer for wastewater treatment. This would help in the development of low cost geopolymer based adsorbent that has a great potential for heavy metal adsorption, which could deliver double benefit in both waste management and wastewater treatment.
  • Publication
    The effect of different ratio bottom ash and fly ash geopolymer brick on mechanical properties for non-loading application
    This paper studies the finding of strength and water absorption of geopolymer bricks using bottom ash and fly ash as a geopolymer raw material for non-loading application with minimum strength. The study has been conducted to produce bottom ash and fly ash geopolymer bricks by varying the ratio of fly ash-to-bottom ash, solid-to-liquid and sodium silicate (Na2SiO3)-to-sodium hydroxide (NaOH) in the mixing process. The compressive strength range between 3.8-4.5 MPa was obtained due to the minimum strength of non-loading application with 70°C curing temperature within 24 hours at 7 days of ageing. The optimum ratio selected of bottom ash-to-fly ash, solid-to-liquid and Na2SiO3-to-NaOH are 1:2, 2.0 and 4.0 respectively. The water absorption result is closely related to the amount of bottom ash used in the mix design.
  • Publication
    Studies of geopolymerization route for metakaolin geopolymeric materials
    Investigation on production of metakaolin geopolymeric powder was aimed to increase the productivity and application of geopolymer products. Geopolymerization process was applied in the manufacturing of metakaolin geopolymeric powder to be used in geopolymer synthesis. Geopolymer slurry was made by alkaline activation of metakaolin in alkali activator solution (a mixture of NaOH and sodium silicate solutions). The geopolymer slurry was heated in an oven to produce pre-cured paste and then pulverized to get uniform particle size geopolymeric powder. By adopting the concept of “just add water”, the metakaolin geopolymeric powder was mixed with water and then oven-cured to produce resulting geopolymer pastes. The physical and mechanical properties of geopolymeric powder and resulting geopolymer pastes, such as workability, setting time, bulk density and compressive strength were studied. These geopolymeric powder and resulting geopolymer pastes were also characterized by using SEM/EDX, XRD and FTIR analyses. The results showed that the optimum conditions for producing highest strength resulting paste are by using 8M of NaOH solution, solids/liquid ratio of 0.80, an activator ratio of 0.20, pre-curing of 80°C for 4 hours, 22% of mixing water and curing regime of 60°C for 72 hours. The resulting geopolymer pastes have low bulk density and were potential for a lightweight material. Upon the mixing of water with geopolymeric powder, densification of the structure occurred with the formation of compact geopolymer gels. The geopolymeric powder and resulting pastes showed the combination of amorphous and crystalline phases as analyzed by XRD. After ageing, the intensities of zeolites crystalline phases increased and this emphasized the benefit of zeolites in strength development of resulting pastes. Moreover, FTIR analysis revealed the growth of geopolymer bonding with ages. The optimum SiO2/Al2O3, Na2O/SiO2, H2O/Na2O and Na2O/Al2O3 oxide-molar ratios were 3.10, 0.37, 14.23 and 1.15, respectively. Study on the oxide-molar ratios concluded that mechanical properties of geopolymer paste were influenced most significantly by Na2O/Al2O3 and H2O/Na2O molar ratios. This study clearly demonstrates that the production of metakaolin geopolymeric powder was able to be used in manufacturing geopolymer pastes.
  • Publication
    Formulation, mechanical properties and phase analysis of fly ash geopolymer with ladle furnace slag replacement
    ( 2021)
    Ng Hui-Teng
    ;
    ;
    Kong Ern Hun
    ;
    ; ;
    Hasniyati Md Razi
    ;
    Ng Yong-Sing
    This paper presents the formulation of fly ash (FA) geopolymer and the incorporation of ladle furnace slag (LFS) as a replacement to FA in geopolymer formation. The formulation of the LFS replacement was set at 10–40 wt.%. The geopolymer was formed by mixing FA and LFS with a sodium-based alkali activator. The FA geopolymer had a compressive strength of 38.9 MPa with the optimum formulation of 8 M NaOH concentration, AS/AA ratio of 3, and AA ratio of 1.5. The compressive strength was affected more significantly by the amorphous content. The most influential factors affecting the properties of FA geopolymer were: AS/AA ratio > AA ratio > NaOH concentration. Replacing LFS led to very little (4.1%) increment in the compressive strength. The LFS had little contribution in supplying Si, Al and Ca for the formation of the N-A-S-H and C-A-S-H network. But LFS acted as a filler and improved the compactness of the FA geopolymer. The mechanical performance of FA/LFS geopolymer was not governed by the amorphous content like the FA geopolymer, as LFS addition contributed to increasing crystalline content. New crystalline phases of calcite and CSH due to the addition of LFS helped to retain the compressive strength of FA geopolymer. Nevertheless, the outcome of the study proved that LFS can be blended with FA to produce geopolymers without severe deterioration in mechanical strength. LFS can be potentially added in geopolymers as filler to produce geopolymer mortar.
  • Publication
    Improvements of flexural properties and thermal performance in thin geopolymer based on fly ash and ladle furnace slag using borax decahydrates
    ( 2022)
    Ng Yong-Sing
    ;
    ; ; ;
    Phakkhananan Pakawanit
    ;
    Petrica Vizureanu
    ;
    Mohd Suhaimi Khalid
    ;
    Ng Hui-Teng
    ;
    Hang Yong-Jie
    ;
    Marcin Nabiałek
    ;
    Paweł Pietrusiewicz
    ;
    Sebastian Garus
    ;
    Wojciech Sochacki
    ;
    Agata Śliwa
    This paper elucidates the influence of borax decahydrate addition on the flexural and thermal properties of 10 mm thin fly ash/ladle furnace slag (FAS) geopolymers. The borax decahydrate (2, 4, 6, and 8 wt.%) was incorporated to produce FAB geopolymers. Heat treatment was applied with temperature ranges of 300 °C, 600 °C, 900 °C, 1000 °C and 1100 °C. Unexposed FAB geopolymers experienced a drop in strength due to a looser matrix with higher porosity. However, borax decahydrate inclusion significantly enhanced the flexural performance of thin geopolymers after heating. FAB2 and FAB8 geopolymers reported higher flexural strength of 26.5 MPa and 47.8 MPa, respectively, at 1000 °C as compared to FAS geopolymers (24.1 MPa at 1100 °C). The molten B2O3 provided an adhesive medium to assemble the aluminosilicates, improving the interparticle connectivity which led to a drastic strength increment. Moreover, the borax addition reduced the glass transition temperature, forming more refractory crystalline phases at lower temperatures. This induced a significant strength increment in FAB geopolymers with a factor of 3.6 for FAB8 at 900 °C, and 4.0 factor for FAB2 at 1000 °C, respectively. Comparatively, FAS geopolymers only achieved 3.1 factor in strength increment at 1100 °C. This proved that borax decahydrate could be utilized in the high strength development of thin geopolymers.
  • Publication
    Experimental investigation of chopped steel wool fiber at various ratio reinforced cementitious composite panels
    ( 2021)
    Akrm A. Rmdan Amer
    ;
    ; ;
    Ikmal Hakem A Aziz
    ;
    ; ;
    Hetham A.R. Amer
    The flexural toughness of chopped steel wool fiber reinforced cementitious composite panels was investigated. Reinforced cementitious composite panels were produced by mixing of chopped steel wool fiber with a ratio range between 0.5% to 6.0% and 0.5% as a step increment of the total mixture weight, where the cement to sand ratio was 1:1.5 with water to cement ratio of 0.45. The generated reinforced cementitious panels were tested at 28 days in terms of load-carrying capacity, deflection capacities, post-yielding effects, and flexural toughness. The inclusion of chopped steel wool fiber until 4.5% resulted in gradually increasing load-carrying capacity and deflection capacities while, provides various ductility, which would simultaneously the varying of deflection capability in the post-yielding stage. Meanwhile, additional fiber beyond 4.5% resulted in decreased maximum load-carrying capacity and increase stiffness at the expense of ductility. Lastly, the inclusion of curves gradually.
  • Publication
    Recent developments in steelmaking industry and potential alkali activated based steel waste: A comprehensive review
    ( 2022)
    Ikmal Hakem Aziz
    ;
    ; ; ;
    Long Yuan Li
    ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Ovidiu Nemes
    ;
    Shaik Numan Mahdi
    The steel industry is responsible for one-third of all global industrial CO2 emissions, putting pressure on the industry to shift forward towards more environmentally friendly production methods. The metallurgical industry is under enormous pressure to reduce CO2 emissions as a result of growing environmental concerns about global warming. The reduction in CO2 emissions is normally fulfilled by recycling steel waste into alkali-activated cement. Numerous types of steel waste have been produced via three main production routes, including blast furnace, electric arc furnace, and basic oxygen furnace. To date, all of the steel waste has been incorporated into alkali activation system to enhance the properties. This review focuses on the current developments over the last ten years in the steelmaking industry. This work also summarizes the utilization of steel waste for improving cement properties through an alkali activation system. Finally, this work presents some future research opportunities with regard to the potential of steel waste to be utilized as an alkali-activated material.
  • Publication
    Asas Geopolimer Teori & Amali
    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.