Now showing 1 - 10 of 17
  • Publication
    Comparison of hook and straight steel fibers addition on malaysian fly ash-based geopolymer concrete on the slump, density, water absorption and mechanical properties
    ( 2021) ; ;
    Ratnasamy Muniandy
    ;
    ;
    Katarzyna Błoch
    ;
    Bartłomiej Jeż
    ;
    Sebastian Garus
    ;
    Paweł Palutkiewicz
    ;
    ;
    Geopolymer concrete has the potential to replace ordinary Portland cement which can reduce carbon dioxide emission to the environment. The addition of different amounts of steel fibers, as well as different types of end-shape fibers, could alter the performance of geopolymer concrete. The source of aluminosilicate (fly ash) used in the production of geopolymer concrete may lead to a different result. This study focuses on the comparison between Malaysian fly ash geopolymer concrete with the addition of hooked steel fibers and geopolymer concrete with the addition of straight-end steel fibers to the physical and mechanical properties. Malaysian fly ash was first characterized by X-ray fluorescence (XRF) to identify the chemical composition. The sample of steel fiber reinforced geopolymer concrete was produced by mixing fly ash, alkali activators, aggregates, and specific amounts of hook or straight steel fibers. The steel fibers addition for both types of fibers are 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume percentage. The samples were cured at room temperature. The physical properties (slump, density, and water absorption) of reinforced geopolymer concrete were studied. Meanwhile, a mechanical performance which is compressive, as well as the flexural strength was studied. The results show that the pattern in physical properties of geopolymer concrete for both types of fibers addition is almost similar where the slump is decreased with density and water absorption is increased with the increasing amount of fibers addition. However, the addition of hook steel fiber to the geopolymer concrete produced a lower slump than the addition of straight steel fibers. Meanwhile, the addition of hook steel fiber to the geopolymer concrete shows a higher density and water absorption compared to the sample with the addition of straight steel fibers. However, the difference is not significant. Besides, samples with the addition of hook steel fibers give better performance for compressive and flexural strength compared to the samples with the addition of straight steel fibers where the highest is at 1.0% of fibers addition.
  • Publication
    Optimization of MEH-PPV based single and double-layer TOLED structure by numerical simulation
    In this work, we simulated and characterized Poly [2-methoxy-5-(2’-ethylhexyloxy)-1, 4-phenylene vinylene] (MEH-PPV) based single and double-layer TOLED by using Silvaco ATLAS device simulator to achieve prominent values of electrical and optical properties of the device. MEH-PPV were used as the emitting layer (EML) in the single-layer, while addition of Poly [(3,4-ethylene dioxythiophene)-poly(styrene sulfonate)] (PEDOT-PSS) as the electron transport layer (ETL) were conducted in double-layer TOLED simulation. The EML and ETL thickness in both structures were varied between 10 – 150 nm, respectively, to observe and understand the underlying physics of the relation in the layer thickness to the electrical and optical characteristics. Furthermore, variation of the EML/ETL thickness ratio from 1:1 to 5:1 (with thickness in between 10 to 50 nm) had also been conducted. From this work, it is understood that the thickness of the EML layer plays the most important role in TOLED, and by balancing the carrier injections and recombination rate in appropriate EML/ETL thickness ratio, the electrical and optical properties can be improved. By optimizing the EML/ETL thickness and thickness ratio, an optimal forward current of 1.41 mA and luminescent power of 1.93e-18 W/μm has been achieved with both MEH-PPV and PEDOT-PSS layer thickness of 10 nm (1:1 ratio), respectively. The results from this work will assist the improvement of TOLED device to be implemented widely in low power and transparent electronic appliances.
  • Publication
    Phase formation and microstructure analyses of La0.6Sr0.4CoO3-δ-BaCe0.54Zr0.36Y0.1O2.95composite material prepared by solid state mixing method
    (IOP Publishing, 2020)
    Abdullah Abdul Samat
    ;
    Muhammad Syafiq Amsyar Ahmad Pisor
    ;
    ;
    Nafisah Osman
    ;
    ; ;
    Nurul Akidah Baharuddin
    A composite material of La0.6Sr0.4CoO3-δ-BaCe0.54Zr0.36Y0.1O2.95 (LSC-BCZY) was prepared by mixing sol-gel derived LSC and BCZY powders in different weight percentage (wt%) ratio of LSC to BCZY (LSC:BCZY). The prepared composite powders were denoted as S1 (30:70), S2 (50:50) and S3 (70:30). The powders were characterized by an X-ray diffractometer (XRD), a Brunauer-Emmett-Teller (BET) surface area and porosity analyzer and a scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) spectrometer. XRD analysis confirmed that all of the powders were not pure enough due to the presence of impurity phases such as barium carbonate (BaCO3) and strontium carbonate (SrCO3) and unknown phases. S1 powder has the highest amount of impurity phases (81.19 %) and the largest BET surface area (4.82 m2 g−1). All of the powders formed typical clump-like network structure as proven by SEM analysis. EDX analysis revealed that the elemental compositions of La, Sr and Zr were deviated from their nominal mole fractions in all powders due to the Zr-rich clusters formation. The results indicate that the formation of pure and homogenous LSC-BCZY composite powder prepared by solid state mixing method requires further modification and improvement of the preparation method.
  • Publication
    Effect of winding speed in epoxy glass composites for new fabricated filament winding machin
    The production of the glass fiber reinforced epoxy pipes is produced by filament winding process due to of its low costs, convenient and easy to install. The main objectives of this research is to optimize new fabricated filament winding machine and investigate the effect of winding speed. The problems for a new fabricated filament winding machine that must be optimized at first and lack of data for parameter in winding speed. The production by using filament winding process can be produce varieties of products such as tanks, pipes and vessels. The production of glass reinforced epoxy pipes of filament winding process was used different of winding speed levels. The new fabricated filament winding machine have 6 different winding speed that must be tested to get the optimum mechanical strength results. The process was stopped when the thickness of the samples is about 5.5mm wall thickness. The samples were tested with density for physical test and compressive strength for mechanical testing. The optimum winding speed to produce high mechanical strength for this new fabricated filament winding machine is winding speed two and the angle of the winding for speed 2 is 55°. This study, helps to determine winding speed for calibrate new filament winding.
      6  27
  • Publication
    Interaction of Geopolymer Filler and Alkali Molarity Concentration towards the Fire Properties of Glass-Reinforced Epoxy Composites Fabricated Using Filament Winding Technique
    This paper aims to find out the effect of different weight percentages of geopolymer filler in glass-reinforced epoxy pipe, and which can achieve the best mechanical properties and adhesion between high calcium pozzolanic-based geopolymer matrices. Different weight percentages and molarities of epoxy hardener resin and high calcium pozzolanic-based geopolymer were injected into the glass fiber. By manually winding filaments, composite samples were produced, and they were then allowed to cure at room temperature. To determine how well the geopolymer matrices adhere to the fiber reinforcement, the microstructure of the composites’ surfaces and perpendicular sections were examined. Maximum values of compressive strength and compressive modulus were 94.64 MPa and 2373.58 MPa, respectively, for the sample with a weight percentage of filler loading of 30 wt% for an alkali concentration of 12 M. This is a relatively wide range of geopolymer weight percentage of filler loading from 10 wt% to 40 wt%, at which we can obtain high compressive properties. By referring to microstructural analysis, adhesion, and interaction of the geopolymer matrix to glass fiber, it shows that the filler is well-dispersed and embedded at the fiber glass, and it was difficult to determine the differences within the range of optimal geopolymer filler content. By determining the optimum weight percent of 30 wt% of geopolymer filler and microstructural analysis, the maximum parameter has been achieved via analysis of high calcium pozzolanic-based geopolymer filler. Fire or elevated temperature represents one of the extreme ambient conditions that any structure may be exposed to during its service life. The heat resistance or thermal analysis between glass-reinforced epoxy (GRE) pipe and glass-reinforced epoxy pipe filled with high calcium pozzolanic-based geopolymer filler was studied by investigating burning tests on the samples, which shows that the addition of high calcium pozzolanic-based geopolymer filler results in a significant reduction of the melted epoxy.
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  • Publication
    Mechanical Effect on Different Geopolymer Filler in Glass Reinforced Epoxy Composite
    Glass reinforced epoxy are widely known in oil and gas industry as glass reinforced epoxy pipe. However, glass reinforced epoxy has limitation such as demanding careful handling due fabrication, installation and transportation because of brittle nature itself and low compressive strength. The aim of this research is to characterize and study the effect of different geopolymer filler in the glass reinforced epoxy pipe composites. Filament winding method will be used in producing glass reinforced epoxy composite. Samples will be prepared with different weight percentage of geopolymer filler loading and different types of geopolymer filler which is fly ash-based geopolymer and kaolin-based geopolymer with 10wt% - 40wt% of geopolymer filler loading. Microstructure was obtained by using Scanning Electron Microscopy showed spherical shaped of fly ash raw material and plate-like structure for kaolin raw material. After undergoes the mechanical testing involved compressive test, pipe sample of glass reinforced epoxy filled with 20 wt% of fly ash-based geopolymer filler showed the best performances above them all. The compressive strength value was 43.05 MPa. Glass reinforced epoxy composite pipe filled with different geopolymer are not widely used in this research area. Therefore, by using geopolymer as a filler can improve the properties of glass reinforced epoxy composite pipe. Hence, a waste material like geopolymer can reduce the cost of material and improve the environment.
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  • Publication
    Interaction of geopolymer filler and alkali molarity concentration towards the fire properties of glass-reinforced epoxy composites fabricated using filament winding technique
    This paper aims to find out the effect of different weight percentages of geopolymer filler in glass-reinforced epoxy pipe, and which can achieve the best mechanical properties and adhesion between high calcium pozzolanic-based geopolymer matrices. Different weight percentages and molarities of epoxy hardener resin and high calcium pozzolanic-based geopolymer were injected into the glass fiber. By manually winding filaments, composite samples were produced, and they were then allowed to cure at room temperature. To determine how well the geopolymer matrices adhere to the fiber reinforcement, the microstructure of the composites’ surfaces and perpendicular sections were examined. Maximum values of compressive strength and compressive modulus were 94.64 MPa and 2373.58 MPa, respectively, for the sample with a weight percentage of filler loading of 30 wt% for an alkali concentration of 12 M. This is a relatively wide range of geopolymer weight percentage of filler loading from 10 wt% to 40 wt%, at which we can obtain high compressive properties. By referring to microstructural analysis, adhesion, and interaction of the geopolymer matrix to glass fiber, it shows that the filler is well-dispersed and embedded at the fiber glass, and it was difficult to determine the differences within the range of optimal geopolymer filler content. By determining the optimum weight percent of 30 wt% of geopolymer filler and microstructural analysis, the maximum parameter has been achieved via analysis of high calcium pozzolanic-based geopolymer filler. Fire or elevated temperature represents one of the extreme ambient conditions that any structure may be exposed to during its service life. The heat resistance or thermal analysis between glass-reinforced epoxy (GRE) pipe and glass-reinforced epoxy pipe filled with high calcium pozzolanic-based geopolymer filler was studied by investigating burning tests on the samples, which shows that the addition of high calcium pozzolanic-based geopolymer filler results in a significant reduction of the melted epoxy.
      6  23
  • Publication
    Mechanical effects on different solid to liquid ratio of geopolymer filler in epoxy resin
    Geopolymer is formed from the alkali activation of materials rich in Si and Al content with the addition of a silicate solution to enhance the properties of the materials. This paper presents research on the mechanical properties of fly ash-based geopolymer filler in epoxy resin by varying different solid to liquid ratios using sodium hydroxide and sodium silicate as the alkaline activator. However, the common problem observed from the solid to liquid ratio is the influence of curing time and compressive strength of geopolymer to have the best mechanical property. The mix design for geopolymers of solid to liquid ratio is essential in developing the geopolymer’s mechanical strength. A series of epoxy filled with fly ash-based geopolymer materials with different solid to liquid ratio, which is prepared from 0.5 to 2.5 solid to liquid ratio of alkaline activator. The tensile strength and flexural strength of the epoxy filled with fly ash-based geopolymer materials is determined using Universal Testing Machine under tensile and flexural mode. It was found that the optimum solid to liquid ratio is 2.0, with the optimum tensile and flexural strength value. However, both the tensile and flexural properties of epoxy filled with fly ash-based geopolymer suddenly decrease at a 2.5 solid to liquid ratio. The strength is increasing with the increasing solid to liquid ratio sample of geopolymer filler content.
      6  18
  • Publication
    Low Density, High Compressive Strength: Experimental Investigation with Various Particle Sizes of Sand for Different Mix Designs of Cement Mortar Manufacturing
    ( 2020-07-09)
    Rmdan Amer A.A.
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    ; ;
    Faheem Mohd Tahir M.
    ;
    Wazien Ahmad Zailani W.
    ;
    Concrete density was optimised by substituting part of the normal-density aggregates (fine aggregate, coarse aggregate, or both) with that of comparable quantities of low-density aggregate, which enhanced structural efficiency (strength to density ratio), improved hydration and decreased transportation costs. These days, focus is given on enhancing the characteristics of concretes in order to make them more efficient. A factor associated in compressive strength, packing particle, water absorption and density is concrete proportioning. A good proportioning mix results in greater strength for concrete at optimum density and specified age. The filler effect is regarded as a physical feature pertaining to small particles for a concrete material since it allows generating extra compressive strength by filling voids by making mortar or concrete more homogeneous. This behaviour allows conferring additional compressive strength as well as optimise or minimise the concrete's density without having to use a pozzolanic reaction or a chemical reaction. Mainly, this objective has been implemented through using three different lightweight particle sizes of sand group a-(1.18 mm ≤ Sand size < 200 m), b-(2.36 mm ≤ Sand size < 1.18 mm) and (5.0 mm ≤ Sand size < 2.36 mm). The parameters that are taken consideration during the investigation were sand particle size, water/cement ratio, cement/sand ratio. In general, the results demonstrated that there was a decrease in compressive strength when the sand's particle sizes increased. In case the particle size group (b) and (c) used the decrease rate in compressive strength was 7.97% and 12.39% respectively in comparison with particle size group (a) where the optimum values of the water/cement and cement/sand ratio were used. On the other hand, low density was achieved at the point of the higher compressive strength, whereas 4.4% and 3.66 % increase in the density was recorded over the particle sizes of sand (b and c) respectively. Meanwhile, we put forward the relationships existing between the compressive strength as well as density of concrete mixtures with various proportions of the lightweight aggregates as given above. The conducted experimental studies showed that there were tendencies to possibly utilise various quantities of fine lightweight aggregates as well as their combinations to yield concrete mixtures based on the requirements in practical application. As per the study conclusion, the considered mixtures could be used to yield structural elements that need high compressive strength and lower density.
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