Now showing 1 - 10 of 61
  • Publication
    Fly Ash porous material using geopolymerization process for high temperature exposure
    ( 2012-04-10) ; ; ;
    Mohamed Bnhussain
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    Che Mohd Ruzaidi Ghazali
    ;
    Mohd Izzat Ahmad
    This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash). In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash) synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.
  • Publication
    Thermal insulation properties of insulated concrete
    ( 2019-01-01)
    Shahedan N.F.
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    ; ;
    Kusbiantoro A.
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    Sandu A.V.
    ;
    Naveed A.
    In building development, concrete is world most reliable, durable and versatile in construction materials. However, the heating and cooling system of the building is influenced by outside temperature due to extreme weather or areas condition leads to the consumption of a lot of electrical power. Thermally insulated concretes represent alternative construction materials to improve the thermal efficiency in building development. Various construction materials have different thermal insulation properties and thus, their suitability for various conditions vary. Thermal insulation properties are generally identified through specific heat, thermal conductivity, thermal diffusivity, thermal expansion, and mass loss. This paper present review the thermal insulation properties of variations insulated concrete are presently in growing demand of researchers to comfort and resolve prescribed issues related to insulated concrete in enhancing thermal insulation properties as a passive energy saving building.
  • Publication
    Effect of NaOH molar concentration on microstructure and compressive strength of Dolomite/Fly Ash-Based geopolymers
    ( 2021)
    Emy Aizat Azimi
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    M.A.A. Mohd Salleh
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    ;
    Ikmal Hakem A. Aziz
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    ;
    Jitrin Chaiprapa
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    Petrica Vizureanu
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    Sorachon Yoriya
    ;
    Marcin Nabiałek
    ;
    Jerzy J. Wyslocki
    Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.
  • Publication
    Performance of Sintered Pozzolanic Artificial Aggregates as Coarse Aggregate Replacement in Concrete
    The abundant increase in waste quantities year by year and the depletion of natural resources worldwide are the major concerns among researchers. Recycling and reusing various types of natural or by-product material waste from industry become highlighted in the recent study. The growing demand for concrete and the production of artificial aggregate become crucial in the construction industry. Artificial aggregate can be produced either by sintering, auto-clave or cold bonding method. Although auto-clave and cold bonding methods can minimize energy consumption, the selection of the sintering method always leads to high quality and better properties of artificial aggregates produced. The use of sintering methods to produce artificial aggregate made from pozzolanic material focuses on the use of volcanic ash as raw material activated by geopolymerization process to produce artificial lightweight aggregate-based geopolymer will be summarized in this chapter. This chapter discusses the result of the physical and mechanical properties of artificial lightweight aggregate or known as sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA). The interfacial transition zone (ITZ) of sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA) is presented. The performance of sintered geopolymer volcanic ash artificial lightweight aggregate (SGVA) in concrete is also discussed.
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  • Publication
    Effect of Glass Reinforced Epoxy (GRE) pipe filled with geopolymer materials for piping application: compression properties
    The aim of this paper is to achieve the highest compressive strength of glass reinforced epoxy pipe with the geopolymer filler content of weight percentage that were used in glass reinforced epoxy pipe. The samples were prepared by using the filament winding method. The effect of weight percentage of geopolymer materials in epoxy hardener was studied under mechanical testing, which is using the compression test. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 – 40 weight percentage geopolymer filler which is white clay were prepared. The compression strength of the glass reinforced epoxy pipe filled geopolymer materials is determined using Instron Universal Testing under compression mode. It was found that compressive strength for samples with white clay geopolymer filler are much higher compare to glass reinforced epoxy pipe without geopolymer filler. Moreover, the compressive strength of glass reinforced epoxy pipe filled with white clay geopolymer filler was increased from 10 wt% to 30 wt% of geopolymer content. However, the compressive strength of glass reinforced epoxy pipe with white clay geopolymer filler suddenly decreased when added to 40 wt%. The results indicated that the blending of geopolymer materials in epoxy system can be obtained in this study.
      14  1
  • Publication
    Fabrication of Lightweight Ceramic Materials Using Geopolymer Technology
    Depending on density, lightweight ceramic can be used in several applications such as construction, cutting tools, amour system, wear lining refractories, and wastewater treatment. The growth of lightweight ceramics in such applications becomes a motivation in developing the materials using geopolymer technology. With the uniqueness of geopolymer composition and the help of geopolymerization, high-temperature routes are no longer required to produce ceramic materials. The geopolymer, so called inorganic polymer will convert the amorphous and semi-crystalline phase into a crystalline phase during sintering. The synthesis at low temperatures is energy efficient and more environmentally friendly than older materials. The formation of geopolymer is a polymerization process similar to the polycondensation of an organic polymer. Therefore, the overall process is termed as geopolymerization. The geopolymerization can transfer Al and Si containing wastes into geopolymers with high mechanical strength and highly durable construction materials. The use of kaolin and fly ash as source materials in the formation of geopolymer ceramics could achieve good economic and environmental benefits. This chapter highlights the role of geopolymer systems in the production of ceramic materials for lightweight applications. It covers basic knowledge on ceramics, the formation of geopolymer, fabrication of light-weight ceramic materials using the geopolymer method, and the characterization and properties of the products.
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  • Publication
    The effects of various concentrations of NaOH on the Inter-Particle Gelation of a Fly Ash Geopolymer Aggregate
    ( 2021) ; ; ; ;
    Wojciech Sochacki
    ;
    Rafiza Abdul Razak
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    Katarzyna Błoch
    ;
    Hamzah Fansuri
    Aggregates can be categorized into natural and artificial aggregates. Preserving natural resources is crucial to ensuring the constant supply of natural aggregates. In order to preserve these natural resources, the production of artificial aggregates is beginning to gain the attention of researchers worldwide. One of the methods involves using geopolymer technology. On this basis, this current research focuses on the inter-particle effect on the properties of fly ash geopolymer aggregates with different molarities of sodium hydroxide (NaOH). The effects of synthesis parameters (6, 8, 10, 12, and 14 M) on the mechanical and microstructural properties of the fly ash geopolymer aggregate were studied. The fly ash geopolymer aggregate was palletized manually by using a hand to form a sphere-shaped aggregate where the ratio of NaOH/Na2SiO3 used was constant at 2.5. The results indicated that the NaOH molarity has a significant effect on the impact strength of a fly ash geopolymer aggregate. The highest aggregate impact value (AIV) was obtained for samples with 6 M NaOH molarity (26.95%), indicating the lowest strength among other molarities studied and the lowest density of 2150 kg/m3. The low concentration of sodium hydroxide in the alkali activator solution resulted in the dissolution of fly ash being limited; thus, the inter-particle volume cannot be fully filled by the precipitated gels.
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  • Publication
    Strength development and elemental distribution of dolomite/fly ash geopolymer composite under elevated temperature
    ( 2020-02-01)
    Azimi E.A.
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    Vizureanu P.
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    Sandu A.V.
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    Chaiprapa J.
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    Yoriya S.
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    ;
    Aziz I.H.
    A geopolymer has been reckoned as a rising technology with huge potential for application across the globe. Dolomite refers to a material that can be used raw in producing geopolymers. Nevertheless, dolomite has slow strength development due to its low reactivity as a geopolymer. In this study, dolomite/fly ash (DFA) geopolymer composites were produced with dolomite, fly ash, sodium hydroxide, and liquid sodium silicate. A compression test was carried out on DFA geopolymers to determine the strength of the composite, while a synchrotron Micro-Xray Fluorescence (Micro-XRF) test was performed to assess the elemental distribution in the geopolymer composite. The temperature applied in this study generated promising properties of DFA geopolymers, especially in strength, which displayed increments up to 74.48 MPa as the optimum value. Heat seemed to enhance the strength development of DFA geopolymer composites. The elemental distribution analysis revealed exceptional outcomes for the composites, particularly exposure up to 400°C, which signified the homogeneity of the DFA composites. Temperatures exceeding 400°C accelerated the strength development, thus increasing the strength of the DFA composites. This appears to be unique because the strength of ordinary Portland Cement (OPC) and other geopolymers composed of other raw materials is typically either maintained or decreases due to increased heat.
      2  22
  • Publication
    Fly ash-metakaolin blend geopolymers under thermal exposures: Physical and mechanical performances
    ( 2020-11-02)
    Zulkifly K.
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    ; ; ;
    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.
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  • Publication
    Effect of Solid-to-Liquid Ratio on Thin Fly Ash Geopolymer
    The present work studies the effect of solid-to-liquid (S/L) ratio on the properties of thin fly ash-based geopolymer. The fly ash geopolymers with dimension of 160 mm × 40 mm × 10 mm were synthesised by using various S/L ratios (1.5, 2.0, 2.5, 3.0 and 3.2). The alkali activator was prepared by mixing 10M sodium hydroxide (NaOH) solution and sodium silicate (Na2SiO3) with the Na2SiO3/NaOH ratio of 2.5. The samples were cured at 60°C for 6 hours. The performance of fly ash geopolymers was evaluated by testing the flexural strength after 28 days. Results showed that the S/L ratio had an effect on flexural strength. The optimum flexural strength of 5.12 MPa was achieved by the fly ash geopolymer with S/L ratio of 2.5. However, the flexural strength dropped with higher S/L ratio as the workability decreases. However, further experimental lab work should be carried out as there is less knowledge in the study on the flexural strength of thin fly ash geopolymer.
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